all patent applications , patents , and literature references cited in this specification are hereby incorporated by reference in their entirety . in the case of conflict , the present description , including definitions , is intended to control . 1 . “ nucleic acid ” or “ polynucleotide ” as used herein refers to purine - and pyrimidine - containing polymers of any length , either polyribonucleotides or polydeoxyribonucleotides or mixed polyribopolydeoxyribo nucleotides . this includes single - and double - stranded molecules , i . e ., dna - dna , dna - rna and rna - rna hybrids , as well as “ protein nucleic acids ” ( pna ) formed by conjugating bases to an amino acid backbone . this also includes nucleic acids containing modified bases ( see below ). 2 . “ complementary dna or cdna ” as used herein refers to a dna molecule or sequence that has been enzymatically synthesized from the sequences present in a mrna template , or a clone of such a dna molecule . a “ dna construct ” is a dna molecule or a clone of such a molecule , either single - or double - stranded , which has been modified to contain segments of dna that are combined and juxtaposed in a manner that would not otherwise exist in nature . by way of non - limiting example , a cdna or dna which has no introns , i . e ., is free from non - coding sequences , is inserted adjacent to , or within , exogenous ( e . g ., heterologous ) dna sequences . 3 . a plasmid or , more generally , a vector or “ expression vector ”, is a dna construct containing genetic information that may provide for its replication when inserted into a host cell . a plasmid generally contains at least one gene sequence to be expressed in the host cell , as well as sequences that facilitate such gene expression , including promoters and transcription initiation sites . it may be a linear or closed circular molecule . inserted coding sequences do not occur naturally in the organism from which the vector is derived . 4 . nucleic acids are “ hybridizable ” to each other when at least one strand of one nucleic acid can anneal to another nucleic acid under defined stringency conditions . stringency of hybridization is determined , e . g ., by a ) the temperature at which hybridization and / or washing is performed , and b ) the ionic strength and polarity ( e . g ., formamide ) of the hybridization and washing solutions , as well as other parameters . hybridization requires that the two nucleic acids contain substantially complementary sequences ; depending on the stringency of hybridization , however , mismatches may be tolerated . typically , hybridization of two sequences at high stringency ( such as , for example , in an aqueous solution of 0 . 5 × ssc , at 65 ° c .) requires that the sequences exhibit some high degree of complementarity over their entire sequence . conditions of intermediate stringency ( such as , for example , an aqueous solution of 2 × ssc at 65 ° c .) and low stringency ( such as , for example , an aqueous solution of 2 × ssc at 55 ° c . ), require correspondingly less overall complementarily between the hybridizing sequences . ( 1 × ssc is 0 . 15 m nacl , 0 . 015 m na citrate ). 5 . an “ isolated ” nucleic acid or polypeptide as used herein refers to a component that is removed from its original environment ( for example , its natural environment if it is naturally occurring ). an isolated nucleic acid or polypeptide contains less than about 50 %, preferably less than about 75 %, and most preferably less than about 90 %, of the cellular components with which it was originally associated . 6 . a “ probe ” refers to a nucleic acid that forms a hybrid structure with a sequence in a target region due to complementarily of at least one sequence in the probe with a sequence in the target region . 7 . a nucleic acid that is “ derived from ” a designated sequence refers to a nucleic acid sequence that corresponds to a region of the designated sequence . this encompasses sequences that are homologous or complementary to the sequence , as well as “ sequence - conservative variants ” and “ function - conservative variants ”. sequence - conservative variants are those in which a change of one or more nucleotides in a given codon position results in no alteration in the amino acid encoded at that position . function - conservative variants of c2gnt3 are those in which a given amino acid residue in the polypeptide has been changed without altering the overall conformation and enzymatic activity ( including substrate specificity ) of the native polypeptide ; these changes include , but are not limited to , replacement of an amino acid with one having similar physico - chemical properties ( such as , for example , acidic , basic , hydrophobic , and the like ). 8 . a “ donor substrate ” is a molecule recognized by , e . g ., a core - β1 , 6 - n - acetylglucosaminyltransferase and that contributes an n - acetylglucosaminyl moiety for the transferase reaction . for c2gnt3 , a donor substrate is udp - n - acetylglucosamine . an “ acceptor substrate ” is a molecule , preferably a saccharide or oligosaccharide , that is recognized by , e . g ., an n - acetylglucosaminyltransferase and that is the target for the modification catalyzed by the transferase , i . e ., receives the n - acetylglucosaminyl moiety . for c2gnt3 , acceptor substrates include without limitation oligosaccharides , glycoproteins , o - linked core 1 - glycopeptides , and glycosphingolipids comprising the sequences galβ1 - 3galnac , or glcnacβ1 - 3galnac . 9 . in accordance with the present invention there may be employed conventional molecular biology , microbiology , and recombinant dna techniques within the skill of the art . such techniques are explained fully in the literature . see for example , sambrook , fritsch , maniatis , molecular cloning : a laboratory manual , second edition ( 1989 ) cold spring harbor laboratory press , cold spring harbor , n . y ); dna cloning : a practical approach , volumes i and ii ( d . n . glover ed . 1985 ); oligonucleotide synthesis ( m . j . gait ed . 1984 ); nucleic acid hybridization b . d . hames & amp ; s . j . higgins eds . ( 1985 ); transcription and translation b . d . hames & amp ; s . j . higgins eds ( 1984 ); animal cell culture r . i . freshney , ed . ( 1986 ); immobilized cells and enzymes irl press , ( 1986 ); and b . perbal , a practical guide to molecular cloning ( 1984 ). 10 . the terms “ sequence similarity ” or “ sequence identity ” refer to the relationship between two or more amino acid or nucleic acid sequences , determined by comparing the sequences , which relationship is generally known as “ homology ”. identity in the art also means the degree of sequence relatedness between amino acid or nucleic acid sequences , as the case may be , as determined by the match between strings of such sequences . both identity and similarity can be readily calculated ( computational molecular biology , lesk , a . m ., ed ., oxford university press new york , 1988 ; biocomputing : informatics and genome projects , smith , d . w . ed ., academic press , new york , 1993 ; computer analysis of sequence data , part i , griffin , a . m ., and griffin , h . g . eds . humana press , new jersey , 1994 ; sequence analysis in molecular biology , von heinje , g ., academic press , new york , 1987 ; and sequence analysis primer , gribskov , m . and devereux , s ., eds . m . stockton press , new york , 1991 ). while there are a number of existing methods to measure identity and similarity between two amino acid sequences or two nucleic acid sequences , both terms are well known to the skilled artisan ( sequence analysis in molecular biology , von hinge , g ., academic press , new york , 1987 ; sequence analysis primer , gribskov , m . and devereux , j ., eds . m . stockton press , new york , 1991 ; and carillo , h ., and lipman , d . siam j . applied math ., 48 . 1073 , 1988 ). preferred methods for determining identity are designed to give the largest match between the sequences tested . methods to determine identity are codified in computer programs . preferred computer program methods for determining identity and similarity between two sequences include but are not limited to the gcg program package ( 20 ), blastp , blastn , and fasta ( 21 ). identity or similarity may also be determined using the alignment algorithm of dayhoff et al . ( methods in enzymology 91 : 524 - 545 ( 1983 )]. preferably the nucleic acids of the present invention have substantial sequence identity using the preferred computer programs cited herein , for example greater than 40 %, 45 %, 50 %, 60 %, 70 %, 75 %, 80 %, 85 %, or 90 % identity ; more preferably at least 95 %, 96 %, 97 %, 98 %, or 99 % sequence identity to the sequence shown in seq id no : 1 and fig1 . 11 . the polypeptides of the invention also include homologs of a c2gnt3 polypeptide and / or truncations thereof as described herein . such homologs include polypeptides whose amino acid sequences are comprised of the amino acid sequences of c2gnt3 polypeptide regions from other species that hybridize under selected hybridization conditions ( see discussion of hybridization conditions in particular stringent hybridization conditions herein ) with a probe used to obtain a c2gnt3 polypeptide or to seq id no : 1 . these homologs will generally have the same regions which are characteristic of a c2gnt3 polypeptide . it is anticipated that a polypeptide comprising an amino acid sequence which has at least 40 % identity , at least 45 %, or at least 60 % similarity , preferably at least 60 - 65 % identity or at least 80 - 85 % similarity , more preferably at least 70 - 80 % identity or at least 90 - 95 % similarity , most preferably at least 95 % identity or at least 99 % similarity with the amino acid sequence shown in seq id no : 2 and fig1 and 2 , will be a homolog of a c2gnt3 polypeptide . a percent amino acid sequence similarity or identity is calculated using the methods described herein , preferably the computer programs described herein . the present invention provides the isolated dna molecules , including genomic dna and cdna , encoding the udp - n - acetylglucosamine : n - acetylgalactosamine β1 , 6 n - acetylglucosaminyl - transferase 3 ( c2gnt3 ). c2gnt3 was identified by analysis of genomic survey sequences ( gss ), and cloned based on a genomic clone obtained from a human foreskin fibroblast library . the cloning strategy may be briefly summarized as follows : 1 ) isolation and sequencing of gss clone cit - hsp - 2288b17 . tf ( gss genbank accession number aq005888 ); 2 ) synthesis of oligonucleotides derived from gss sequence information , designated tshc96 and tshc101 ; 3 ) identification , cloning and sequencing of genomic p1 clone gs22597 # 844 / b1 ; 4 ) identification of a novel cdna sequence corresponding to c2gnt3 ; 5 ) confirmatory sequencing of a cdna clone obtained by reverse - transcription - polymerase chain reaction ( rt - pcr ) using human thymus poly a - mrna ; 6 ) construction of expression constructs ; 7 ) expression of the cdna encoding c2gnt3 in sf9 ( spodoptera frugiperda ) cells . more specifically , the isolation of a representative dna molecule encoding a novel third member of the mammalian udp - n - acetylglucosamine : β - n - actylgalactosamine β1 , 6 - n - acetylglucosaminyltransferase family involved the following procedures described below . database searches were performed with the coding sequence of the human c2 / 4gnt ( c2gnt2 ) sequence ( 13 ) using the blastn and the tblastn algorithm with the gss database at the national center for biotechnology information , usa . the blastn algorithm was used to identify clones representing the query gene ( identities of ≧ 95 %), whereas tblastn was used to identify non - identical , but similar gss sequences . gsss with 50 - 90 % nucleotide sequence identity were regarded as different from the query sequence . two gss clones with several apparent short sequence motifs and cysteine residues arranged with similar spacing were selected for further sequence analysis . gss clone cit - hsp - 2288b17 . tf ( gss genbank accession number aq005888 ), derived from a putative homologue to c2 / 4gnt ( c2gnt2 ), was obtained from research genetics inc ., usa . sequencing of this clone revealed a partial open reading frame with significant sequence similarity to c2 / 4gnt ( c2gnt2 ). the coding region of human c2gnt - l ( c2gnt1 ), c2 / 4gnt ( c2gnt2 ) and a bovine homologue was previously found to be organized in one exon (( 22 ),( 15 )). since the 3 ′ sequence available from the c2gnt3 gss was incomplete but likely to be located in a single exon , the missing 3 ′ portion of the open reading frame was obtained by sequencing a genomic p1 clone . the p1 clone was obtained from a human foreskin genomic p1 library ( dupont merck pharmaceutical co . human foreskin fibroblast p1 library ) by screening with the primer pair : tshc96 ( 5 ′- ggtttcaccgtctccaacata - 3 ′, seq id no : 3 ) and tshc101 ( 5 ′- tcgtaaggcacctgatactt - 3 ′, seq id no : 6 ). one genomic clone for c2gnt3 , gs22597 # 844 / b1 was obtained from genome systems inc . dna from p1 phage was prepared as recommended by genome systems inc . the entire coding sequence of the c2gnt3 gene was represented in the clone and sequenced in full using automated sequencing ( abi377 , perkin - elmer ). confirmatory sequencing was performed on a cdna clone obtained by pcr ( 30 cycles at 95 ° c . for 10 sec ; 55 ° c . for 15 sec and 68 ° c . for 2 min 30 sec ) on cdna from human thymus poly a - mrna with the sense primer : the composite sequence contained an open reading frame of 1359 base pairs encoding a putative protein of 453 amino acids with type ii domain structure predicted by the tmpred - algorithm at the swiss institute for experimental cancer research ( isrec ). an expression construct designed to encode amino acid residues 39 - 453 of c2gnt3 was prepared by pcr using p1 dna , and the primer pair : tshc100 ( 5 ′- cgaggatccgcaaaaagacatttacttggtt - 3 ′, seq id no : 5 ) and tshc121 ( 5 ′- agcgaattcttactatcatgatgtggtagtg - 3 ′, seq id no : 9 ) with bamh1 and ecori restriction sites , respectively ( fig2 ). the pcr product was cloned between the bamhi and ecori sites of pacgp67a ( pharmingen ), and the insert was fully sequenced . pacgp67 - c2gnt3 - sol was co - transfected with baculo - gold ™ dna ( pharmingen ) as described previously ( 23 ). recombinant baculovirus was obtained after two successive amplifications in sf9 cells grown in serum - containing medium , and titers of virus were estimated by titration in 24 - well plates with monitoring of enzyme activities . transfection of sf9 - cells with pacgp67 - c2gnt3 - sol resulted in marked increase in glcnac - transferase activity compared to uninfected cells or cells infected with a control construct . c2gnt3 showed significant activity with disaccharide derivatives of o - linked core 1 ( galβ1 - 3galnacα1 - r ). in contrast , no activity was found with core 3 structures ( glcnacβ1 - 3galnacα1 - r ), lacto - n - neotetraose as well as glcnacβ1 - 3gal - me as acceptor substrates indicating that c2gnt3 has no core4gnt and ignt - activity . additionally , no activity could be detected wih α - d - galnac - 1 - para - nitrophenyl indicating that c2gnt3 does not form core 6 ( glcnacβ1 - 6galnacα1 - r ) ( table i ). no substrate inhibition of enzyme activity was found at high acceptor concentrations up to 20 mm core 1 - para - nitrophenyl . c2gnt3 shows strict donor substrate specificity for udp - glcnac , no activity could be detected with udp - gal or udp - galnac ( data not shown ). table i substrate specificities of c2gnt3 and c2gnt1 c2gnt3 a c2gnt1 substrate 2 mm 10 mm 2 mm 10 mm nmol / h / mg nmol / h / mg β - d - gal -( 1 - 3 )- α - d - galnac 6 . 6 14 . 3 9 . 6 19 . 0 β - d - gal -( 1 - 3 )- α - d - galnac - 1 - p - nph 18 . 1 26 . 1 16 . 2 23 . 6 β - d - glcnac -( 1 - 3 )- α - d - galnac - 1 - p - nph & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 α - d - galnac - 1 - p - nph & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 d - galnac & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 lacto - n - neo - tetraose & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 β - d - glcnac -( 1 - 3 )- β - d - gal - 1 - me & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 & lt ; 0 . 1 controls included the pacgp67 - galnac - t3 - sol ( 24 ). the kinetic properties were determined with partially purified enzymes expressed in high five ™ cells . partial purification was performed by consecutive chromatography on amberlite ira - 95 , deae - sephacryl and sp - sepharose essentially as described ( 25 ; 25 ). a human rna master blot containing mrna from fifty healthy human adult and fetal organs ( clontech ) and a human multiple tissue northern blot ( mtnii from clontech ) were probed with a 32 p - labeled probe corresponding to the soluble fragment of c2gnt3 ( base pairs 115 - 1359 ). the autoradiographic analyses showed expression of c2gnt3 predominantly in lymphoid organs and in organs of the gastrointestinal tract with high transcription levels observed in thymus , and lower levels in pbls , lymph node , stomach , pancreas and small intestine ( fig3 a and 3b ). the size of the single transcript was approximately 5 . 5 kilobases , which correlates to the transcript size of 5 . 4 kilobases of the biggest of three transcripts of human c2gnt1 ( fig3 c ). multiple transcripts of c2gnt1 have been suggested to be caused by differential usage of polyadenylation signals , which affects the length of the 3 ′ utr ( 13 ). the c2gnt3 enzyme of the present invention was shown to exhibit o - glycosylation capacity implying that the c2gnt3 gene is vital for correct / full o - glycosylation in vivo as well . a structural defect in the c2gnt3 gene leading to a deficient enzyme or completely defective enzyme would therefore expose a cell or an organism to protein / peptide sequences which were not covered by o - glycosylation as seen in cells or organisms with intact c2gnt3 gene . described in example 5 below is a method for scanning the coding exon for potential structural defects . similar methods could be used for the characterization of defects in the non - coding region of the c2gnt3 gene including the promoter region . in practicing the present invention , many conventional techniques in molecular biology , microbiology , recombinant dna , and immunology , are used . such techniques are well known and are explained fully in , for example , sambrook et al ., 1989 , molecular cloning a laboratory manual , second edition , cold spring harbor laboratory press , cold spring harbor , new york ; dna cloning : a practical approach , volumes i and ii , 1985 ( d . n . glover ed . ); oligonucleotide synthesis , 1984 , ( m . l . gait ed . ); nucleic acid hybridization , 1985 , ( hames and higgins ); transcription and translation , 1984 ( hames and higgins eds . ); animal cell culture , 1986 ( r . i . freshney ed . ); immobilized cells and enzymes , 1986 ( irl press ); perbal , 1984 , a practical guide to molecular cloning ; the series , methods in enzymology ( academic press , inc . ); gene transfer vectors for mammalian cells , 1987 ( j . h . miller and m . p . calos eds ., cold spring harbor laboratory ); methods in enzymology vol . 154 and vol . 155 ( wu and grossman , and wu , eds ., respectively ); immunochemical methods in cell and molecular biology , 1987 ( mayer and waler , eds ; academic press , london ); scopes , 1987 , protein purification : principles and practice , second edition ( springer - verlag , n . y .) and handbook of experimental immunology , 1986 , volumes i - iv ( weir and blackwell eds .). the invention encompasses isolated nucleic acid fragments comprising all or part of the nucleic acid sequence disclosed herein as set forth in fig1 . the fragments are at least about 8 nucleotides in length , preferably at least about 12 nucleotides in length , and most preferably at least about 15 - 20 nucleotides in length . the invention further encompasses isolated nucleic acids comprising sequences that are hybridizable under stringency conditions of 2 × ssc , 55 ° c ., to the sequence set forth in fig1 ; preferably , the nucleic acids are hybridizable at 2 × ssc , 65 ° c . ; and most preferably , are hybridizable at 0 . 5 × ssc , 65 ° c . the nucleic acids may be isolated directly from cells . alternatively , the polymerase chain reaction ( pcr ) method can be used to produce the nucleic acids of the invention , using either chemically synthesized strands or genomic material as templates . primers used for pcr can be synthesized using the sequence information provided herein and can further be designed to introduce appropriate new restriction sites , if desirable , to facilitate incorporation into a given vector for recombinant expression . the nucleic acids of the present invention may be flanked by natural human regulatory sequences , or may be associated with heterologous sequences , including transcriptional control elements such as promoters , enhancers , and response elements , or other sequences such as signal sequences , polyadenylation sequences , introns , 5 ′- and 3 ′- noncoding regions , and the like . preferably , although not necessarily , any two nucleotide sequences to be expressed as a fusion polypeptide are inserted in - frame . the nucleic acids may also be modified by many means known in the art . non - limiting examples of such modifications include methylation , “ caps ”, substitution of one or more of the naturally occurring nucleotides with an analog , internucleotide modifications such as , for example , those with uncharged linkages ( e . g ., methyl phosphonates , phosphotriesters , phosphoroamidates , carbamates , etc .) and with charged linkages ( e . g ., phosphorothioates , phosphorodithioates , etc .). nucleic acids may contain one or more additional covalently linked moieties , such as , for example , proteins ( e . g ., nucleases , toxins , antibodies , signal peptides , poly - l - lysine , etc . ), intercalators ( e . g ., acridine , psoralen , etc . ), chelators ( e . g ., metals , radioactive metals , iron , oxidative metals , etc . ), and alkylators . the nucleic acid may be derivatized by formation of a methyl or ethyl phosphotriester or an alkyl phosphoramidate linkage . furthermore , the nucleic acid sequences of the present invention may also be modified with a label capable of providing a detectable signal , either directly or indirectly . exemplary labels include radioisotopes , fluorescent molecules , biotin , and the like . according to the present invention , useful probes comprise a probe sequence at least eight nucleotides in length that consists of all or part of the sequence from among the sequences as set forth in fig1 or sequence - conservative or function - conservative variants thereof , or a complement thereof , and that has been labelled as described above . the invention also provides nucleic acid vectors comprising the disclosed sequence or derivatives or fragments thereof . a large number of vectors , including plasmid and fungal vectors , have been described for replication and / or expression in a variety of eukaryotic and prokaryotic hosts , and may be used for gene therapy as well as for simple cloning or protein expression . recombinant cloning vectors will often include one or more replication systems for cloning or expression , one or more markers for selection in the host , e . g . antibiotic resistance , and one or more expression cassettes . the inserted coding sequences may be synthesized by standard methods , isolated from natural sources , or prepared as hybrids , etc . ligation of the coding sequences to transcriptional regulatory elements and / or to other amino acid coding sequences may be achieved by known methods . suitable host cells may be transformed / transfected / infected as appropriate by any suitable method including electroporation , cacl 2 mediated dna uptake , fungal infection , microinjection , microprojectile , or other established methods . appropriate host cells included bacteria , archaebacteria , fungi , especially yeast , and plant and animal cells , especially mammalian cells . also included are avian and insect cells . of particular interest are saccharomyces cerevisiae , schizosaccharomyces pombe , pichia pastoris , hansenula polymorpha , neurospora spec ., sf9 cells , c129 cells , 293 cells , and cho cells , cos cells , hela cells , and immortalized mammalian myeloid and lymphoid cell lines . preferred replication systems include m13 , cole1 , 2μ , ars , sv40 , baculovirus , lambda , adenovirus , and the like . a large number of transcription initiation and termination regulatory regions have been isolated and shown to be effective in the transcription and translation of heterologous proteins in the various hosts . examples of these regions , methods of isolation , manner of manipulation , etc . are known in the art . under appropriate expression conditions , host cells can be used as a source of recombinantly produced c2gnt3 derived peptides and polypeptides . advantageously , vectors may also include a transcription regulatory element ( i . e ., a promoter ) operably linked to the c2gnt3 coding portion . the promoter may optionally contain operator portions and / or ribosome binding sites . non - limiting examples of bacterial promoters compatible with e . coli include : β - lactamase ( penicillinase ) promoter ; lactose promoter ; tryptophan ( trp ) promoter ; arabinose bad operon promoter ; lambda - derived p 1 promoter and n gene ribosome binding site ; and the hybrid tac promoter derived from sequences of the trp and lac uv5 promoters . non - limiting examples of yeast promoters include 3 - phosphoglycerate kinase promoter , glyceraldehyde - 3 phosphate dehydrogenase ( gapdh ) promoter , galactokinase ( gal1 ) promoter , galactoepimerase ( gal10 ) promoter , metallothioneine ( cup ) promoter and alcohol dehydrogenase ( adh ) promoter . suitable promoters for mammalian cells include without limitation viral promoters such as that from simian virus 40 ( sv40 ), rous sarcoma virus ( rsv ), adenovirus ( adv ), and bovine papilloma virus ( bpv ). mammalian cells may also require terminator sequences and poly a addition sequences and enhancer sequences which increase expression may also be included ; sequences which cause amplification of the gene may also be desirable . furthermore , sequences that facilitate secretion of the recombinant product from cells , including , but not limited to , bacteria , yeast , and animal cells , such as secretory signal sequences and / or prohormone pro region sequences , may also be included . these sequences are known in the art . nucleic acids encoding wild type or variant polypeptides may also be introduced into cells by recombination events . for example , such a sequence can be introduced into a cell , and thereby effect homologous recombination at the site of an endogenous gene or a sequence with substantial identity to the gene . other recombination - based methods such as nonhomologous recombinations or deletion of endogenous genes by homologous recombination may also be used . the nucleic acids of the present invention find use , for example , as probes for the detection of c2gnt3 in other species or related organisms and as templates for the recombinant production of peptides or polypeptides . these and other embodiments of the present invention are described in more detail below . the present invention encompasses isolated peptides and polypeptides encoded by the disclosed cdna sequence . peptides are preferably at least five residues in length . nucleic acids comprising protein - coding sequences can be used to direct the recombinant expression of polypeptides in intact cells or in cell - free translation systems . the known genetic code , tailored if desired for more efficient expression in a given host organism , can be used to synthesize oligonucleotides encoding the desired amino acid sequences . the phosphoramidite solid support method of ( 26 ), the method of ( 27 ), or other well known methods can be used for such synthesis . the resulting oligonucleotides can be inserted into an appropriate vector and expressed in a compatible host organism . the polypeptides of the present invention , including function - conservative variants of the disclosed sequence , may be isolated from native or from heterologous organisms or cells ( including , but not limited to , bacteria , fungi , insect , plant , and mammalian cells ) into which a protein - coding sequence has been introduced and expressed . furthermore , the polypeptides may be part of recombinant fusion proteins . methods for polypeptide purification are well known in the art , including , without limitation , preparative discontiuous gel elctrophoresis , isoelectric focusing , hplc , reversed - phase hplc , gel filtration , ion exchange and partition chromatography , and countercurrent distribution . for some purposes , it is preferable to produce the polypeptide in a recombinant system in which the protein contains an additional sequence tag that facilitates purification , such as , but not limited to , an affinity ligand , reactive group , and / or a polyhistidine sequence . the polypeptide can then be purified from a crude lysate of the host cell by chromatography on an appropriate solid - phase matrix . alternatively , antibodies produced against a protein or against peptides derived therefrom can be used as purification reagents . other purification methods are possible . the present invention also encompasses derivatives and homologues of polypeptides . for some purposes , nucleic acid sequences encoding the peptides may be altered by substitutions , additions , or deletions that provide for finctionally equivalent molecules , i . e ., function - conservative variants . for example , one or more amino acid residues within the sequence can be substituted by another amino acid of similar properties , such as , for example , positively charged amino acids ( arginine , lysine , and histidine ); negatively charged amino acids ( aspartate and glutamate ); polar neutral amino acids ; and non - polar amino acids . the isolated polypeptides may be modified by , for example , phosphorylation , sulfation , acylation , or other protein modifications . they may also be modified with a label capable of providing a detectable signal , either directly or indirectly , including , but not limited to , radioisotopes and fluorescent compounds . the present invention encompasses antibodies that specifically recognize immunogenic components derived from c2gnt3 . such antibodies can be used as reagents for detection and purification of c2gnt3 . c2gnt3 specific antibodies according to the present invention include polyclonal and monoclonal antibodies . the antibodies may be elicited in an animal host by immunization with c2gnt3 components or may be formed by in vitro immunization of immune cells . the immunogenic components used to elicit the antibodies may be isolated from human cells or produced in recombinant systems . the antibodies may also be produced in recombinant systems programmed with appropriate antibody - encoding dna . alternatively , the antibodies may be constructed by biochemical reconstitution of purified heavy and light chains . the antibodies include hybrid antibodies ( i . e ., containing two sets of heavy chain / light chain combinations , each of which recognizes a different antigen ), chimeric antibodies ( i . e ., in which either the heavy chains , light chains , or both , are fusion proteins ), and univalent antibodies ( i . e ., comprised of a heavy chain / light chain complex bound to the constant region of a second heavy chain ). also included are fab fragments , including fab ′ and f ( ab ) 2 fragments of antibodies . methods for the production of all of the above types of antibodies and derivatives are well known in the art . for example , techniques for producing and processing polyclonal antisera are disclosed in mayer and walker , 1987 , immunochemical methods in cell and molecular biology , ( academic press , london ). the antibodies of this invention can be purified by standard methods , including but not limited to preparative disc - gel elctrophoresis , isoelectric focusing , hplc , reversed - phase hplc , gel filtration , ion exchange and partition chromatography , and countercurrent distribution . purification methods for antibodies are disclosed , e . g ., in the art of antibody purification , 1989 , amicon division , w . r . grace & amp ; co . general protein purification methods are described in protein purification : principles and practice , r . k . scopes , ed ., 1987 , springer - verlag , new york , n . y . anti c2gnt3 antibodies , whether unlabeled or labeled by standard methods , can be used as the basis for immunoassays . the particular label used will depend upon the type of immunoassay used . examples of labels that can be used include , but are not limited to , radiolabels such as 32 p , 125 i , 3 h and 14 c ; fluorescent labels such as fluorescein and its derivatives , rhodamine and its derivatives , dansyl and umbelliferone ; chemiluminescers such as luciferia and 2 , 3 - dihydrophthalazinediones ; and enzymes such as horseradish peroxidase , alkaline phosphatase , lysozyme and glucose - 6 - phosphate dehydrogenase . the antibodies can be tagged with such labels by known methods . for example , coupling agents such as aldehydes , carbodiimides , dimaleimide , imidates , succinimides , bisdiazotized benzadine and the like may be used to tag the antibodies with fluorescent , chemiluminescent or enzyme labels . the general methods involved are well known in the art and are described in , e . g ., chan ( ed . ), 1987 , immunoassay : a practical guide , academic press , inc ., orlando , fla . the nucleic acid molecules , c2gnt3 polypeptide , and antibodies of the invention may be used in the prognostic and diagnostic evaluation of conditions associated with altered expression or activity of a polypeptide of the invention or conditions requiring modulation of a nucleic acid or polypeptide of the invention including thymus - related disorders and proliferative disorders ( e . g . cancer ), and the identification of subjects with a predisposition to such conditions ( see below ). methods for detecting nucleic acid molecules and polypeptides of the invention can be used to monitor such conditions by detecting and localizing the polypeptides and nucleic acids . it would also be apparent to one skilled in the art that the methods described herein may be used to study the developmental expression of the polypeptides of the invention and , accordingly , will provide further insight into the role of the polypeptides . the applications of the present invention also include methods for the identification of substances or compounds that modulate the biological activity of a polypeptide of the invention ( see below ). the substances , compounds , antibodies etc ., may be used for the treatment of conditions requiring modulation of polypeptides of the invention ( see below ). a variety of methods can be employed for the diagnostic and prognostic evaluation of conditions requiring modulation of a nucleic acid or polypeptide of the invention ( e . g . thymus - related disorders , and cancer ), and the identification of subjects with a predisposition to such conditions . such methods may , for example , utilize nucleic acids of the invention , and fragments thereof , and antibodies directed against polypeptides of the invention , including peptide fragments . in particular , the nucleic acids and antibodies may be used , for example , for : ( 1 ) the detection of the presence of c2gnt3 mutations , or the detection of either over - or under - expression of c2gnt3 mrna relative to a non - disorder state or the qualitative or quantitative detection of alternatively spliced forms of c2gnt3 transcripts which may correlate with certain conditions or susceptibility toward such conditions ; or ( 2 ) the detection of either an over - or an under - abundance of a polypeptide of the invention relative to a non - disorder state or the presence of a modified ( e . g ., less than full length ) polypeptide of the invention which correlates with a disorder state , or a progression toward a disorder state . the methods described herein may be performed by utilizing pre - packaged diagnostic kits comprising at least one specific nucleic acid or antibody described herein , which may be conveniently used , e . g ., in clinical settings , to screen and diagnose patients and to screen and identify those individuals exhibiting a predisposition to developing a disorder . nucleic acid - based detection techniques and peptide detection techniques are described below . the samples that may be analyzed using the methods of the invention include those that are known or suspected to express c2gnt3 nucleic acids or contain a polypeptide of the invention . the methods may be performed on biological samples including but not limited to cells , lysates of cells which have been incubated in cell culture , chromosomes isolated from a cell ( e . g . a spread of metaphase chromosomes ), genomic dna ( in solutions or bound to a solid support such as for southern analysis ), rna ( in solution or bound to a solid support such as for northern analysis ), cdna ( in solution or bound to a solid support ), an extract from cells or a tissue , and biological fluids such as serum , urine , blood , and csf . the samples may be derived from a patient or a culture . the nucleic acid molecules of the invention allow those skilled in the art to construct nucleotide probes for use in the detection of nucleic acid sequences of the invention in biological materials . suitable probes include nucleic acid molecules based on nucleic acid sequences encoding at least 5 sequential amino acids from regions of the c2gnt3 polypeptide ( see seq id no : 1 ), preferably they comprise 15 to 50 nucleotides , more preferably 15 to 40 nucleotides , most preferably 15 - 30 nucleotides . a nucleotide probe may be labelled with a detectable substance such as a radioactive label that provides for an adequate signal and has sufficient half - life such as 32 p , 3 h , 14 c or the like . other detectable substances that may be used include antigens that are recognized by a specific labelled antibody , fluorescent compounds , enzymes , antibodies specific for a labelled antigen , and luminescent compounds . an appropriate label may be selected having regard to the rate of hybridization and binding of the probe to the nucleotide to be detected and the amount of nucleotide available for hybridization . labelled probes may be hybridized to nucleic acids on solid supports such as nitrocellulose filters or nylon membranes as generally described in sambrook et al , 1989 , molecular cloning , a laboratory manual ( 2nd ed .). the nucleic acid probes may be used to detect c2gnt3 genes , preferably in human cells . the nucleotide probes may also be used for example in the diagnosis or prognosis of conditions such as thymus - related disorders and cancer , and in monitoring the progression of these conditions , or monitoring a therapeutic treatment . the probe may be used in hybridisation techniques to detect a c2gnt3 gene . the technique generally involves contacting and incubating nucleic acids ( e . g . recombinant dna molecules , cloned genes ) obtained from a sample from a patient or other cellular source with a probe of the present invention under conditions favourable for the specific annealing of the probes to complementary sequences in the nucleic acids . alter incubation , the non - annealed nucleic acids are removed , and the presence of nucleic acids that have hybridized to the probe if any are detected . the detection of nucleic acid molecules of the invention may involve the amplification of specific gene sequences using an amplification method ( e . g . pcr ), followed by the analysis of the amplified molecules using techniques known to those skilled in the art . suitable primers can be routinely designed by one of skill in the art . for example , primers may be designed using commercially available software , such as oligo 4 . 06 primer analysis software ( national biosciences , plymouth , minn .) or another appropriate program , to be about 22 to 30 nucleotides in length , to have a gc content of about 50 % or more , and to anneal to the template at temperatures of about 60 ° c . to 72 ° c . genomic dna may be used in hybridization or amplification assays of biological samples to detect abnormalities involving c2gnt3 nucleic acid structure , including point mutations , insertions , deletions , and chromosomal rearrangements . for example , direct sequencing , single stranded conformational polymorphism analyses , heteroduplex analysis , denaturing gradient gel electrophoresis , chemical mismatch cleavage , and oligonucleotide hybridization may be utilized . genotyping techniques known to one skilled in the art can be used to type polymorphisms that are in close proximity to the mutations in a c2gnt3 gene . the polymorphisms may be used to identify individuals in families that are likely to carry mutations . if a polymorphism exhibits linkage disequalibrium with mutations in the g2gnt3 gene , it can also be used to screen for individuals in the general population likely to carry mutations . polymorphisms which may be used include restriction fragment length polymorphisms ( rflps ), single - nucleotide polymorphisms ( snp ), and simple sequence repeat polymorphisms ( sslps ). a probe or primer of the invention may be used to directly identify rflps . a probe or primer of the invention can additionally be used to isolate genomic clones such as yacs , bacs , pacs , cosmids , phage or plasmids . the dna in the clones can be screened for sslps using hybridization or sequencing procedures . hybridization and amplification techniques described herein may be used to assay qualitative and quantitative aspects of c2gnt3 expression . for example rna may be isolated from a cell type or tissue known to express c2gnt3 and tested utilizing the hybridization ( e . g . standard northern analyses ) or pcr techniques referred to herein . the techniques may be used to detect differences in transcript size that may be doe to normal or abnormal alternative splicing . the techniques may be used to detect quantitative differences between levels of full length and / or alternatively splice transcripts detected in normal individuals relative to those individuals exhibiting symptoms of a disease . the primers and probes may be used in the above described methods in situ i . e directly on tissue sections ( fixed and / or frozen ) of patient tissue obtained from biopsies or resections . oligonucleotides or longer fragments derived from any of the nucleic acid molecules of the invention may be used as targets in a microarray . the microarray can be used to simultaneously monitor the expression levels of large numbers of genes and to identify genetic variants , mutations , and polymorphisms . the information from the microarray may be used to determine gene function , to understand the genetic basis of a disorder , to identify predisposition to a disorder , to treat a disorder , to diagnose a disorder , and to develop and monitor the activities of therapeutic agents . the preparation , use , and analysis of micro arrays are well known to a person skilled in the art . ( see , for example , brennan , t . m ., et al . ( 1995 ), u . s . pat . no . 5 , 474 , 796 ; schena et al . ( 1996 ), proc . natl . acad . sci . 93 : 10614 - 10619 ; baldeschweiler et al . ( 1995 ), pct application wo95 / 251116 ; shalon , d ., et al . ( 1995 ), pct application wo95 / 35505 ; heller , r . a ., et al . ( 1997 ), proc . natl . acad . sci . 94 : 2150 - 2155 ; and heller , m . j ., et al . ( 1997 ), u . s . pat . no . 5 , 605 , 662 .) antibodies specifically reactive with a c2gnt3 polypeptide , or derivatives , such as enzyme conjugates or labeled derivatives , may be used to detect c2gnt3 polypeptides in various biological materials . they may be used as diagnostic or prognostic reagents and they may be used to detect abnormalities in the level of c2gnt3 polypeptides , expression , or abnormalities in the structure , and / or temporal , tissue , cellular , or subcellular location of the polypeptides . antibodies may also be used to screen potentially therapeutic compounds in vitro to determine their effects on a condition such as a thymus - related disorder or cancer . in vitro immunoassays may also be used to assess or monitor the efficacy of particular therapies . preferably , antibodies for use in a detection assay have a dissociation constant lower than 1 μm , even more preferably lower than or about 10 nm . the antibodies of the invention may also be used in vitro to determine the level of c2gnt3 polypeptide expression in cells genetically engineered to produce a c2gnt3 polypeptide . the antibodies may be used to detect and quantify polypeptides of the invention in a sample in order to determine their role in particular cellular events or pathological states , and to diagnose and treat such pathological states . in particular , the antibodies of the invention may be used in immuno - histochemical analyses , for example , at the cellular and sub - subcellular level , to detect a polypeptide of the invention , to localize it to particular cells and tissues , and to specific subcellular locations , and to quantitate the level of expression . the antibodies may be used in any known immunoassays that rely on the binding interaction & gt ;& gt ; between an antigenic determinant of a polypeptide of the invention , and the antibodies . examples of such assays are radio immunoassays , enzyme immunoassays ( e . g . elisa ), immunofluorescence , immunoprecipitation , latex agglutination , hemagglutination , and histochemical tests , cytochemical techniques known in the art for localizing antigens using light and electron microscopy may be used to detect a polypeptide of the invention . generally , an antibody of the invention may be labelled with a detectable substance and a polypeptide may be localised in tissues and cells based upon the presence of the detectable substance . various methods of labelling polypeptides are known in the art and may be used . examples of detectable substances include , but are not limited to , the following : radioisotopes ( e . g ., 3 h , 14 c , 35 s , 125 i , 131 i ), fluorescent labels ( e . g ., fitc , rhodamine , lanthanide phosphors ), luminescent labels such as luminol , enzymatic labels ( e . g ., horseradish peroxidase , β - galactosidase , luciferase , alkaline phosphatase , acetylcholinesterase ), biotinyl groups ( which can be detected by marked avidin e . g ., streptavidin containing a fluorescent marker or enzymatic activity that can be detected by optical or calorimetric methods ), predetermined polypeptide epitopes recognized by a secondary reporter ( e . g ., leucine zipper pair sequences , binding sites for secondary antibodies , metal binding domains , epitope tags ). in some embodiments , labels are attached via spacer arms of various lengths to reduce potential steric hindrance . antibodies may also be coupled to electron dense substances , such as ferritin or colloidal gold , which are readily visualised by electron microscopy . the antibody or sample may be immobilized on a carrier or solid support which is capable of immobilizing cells , antibodies , etc . for example , the carrier or support may be nitrocellulose , or glass , polyacrylamides , gabbros , and magnetite . the support material may have any possible configuration including spherical ( e . g . bead ), cylindrical ( e . g . inside surface of a test tube or well , or the external surface of a rod ), or flat ( e . g . sheet , test strip ). indirect methods may also be employed in which the primary antigen - antibody reaction is amplified by the introduction of a second antibody , having specificity for the antibody reactive against a polypeptide of the invention . by way of example , if the antibody having specificity against a polypeptide of the invention is a rabbit igg antibody , the second antibody may be goat anti - rabbit gamma - globulin labelled with a detectable substance as described herein . where a radioactive label is used as a detectable substance , a polypeptide of the invention may be localized by radioautography . the results of radioautography may be quantitated by determining the density of particles in the radioautographs by various optical methods , or by counting the grains . a polypeptide of the invention may also be detected by assaying for c2gnt3 activity as described herein . for example , a sample may be reacted with an acceptor substrate and a donor substrate under conditions where a c2gnt3 polypeptide is capable of transferring the donor substrate to the acceptor substrate to produce a donor substrate - acceptor substrate complex . the methods described herein are designed to identify substances and compounds that modulate the expression or biological activity of a c2gnt3 polypeptide including substances that interfere with or enhance the expression or activity of a c2gnt3 polypeptide . substances and compounds identified using the methods of the invention include but are not limited to peptides such as soluble peptides including ig - tailed fusion peptides , members of random peptide libraries and combinatorial chemistry - derived molecular libraries made of d - and / or l - configuration amino acids , phosphopeptides ( including members of random or partially degenerate , directed phosphopeptide libraries ), antibodies [ e . g . polyclonal , monoclonal , humanized , anti - idiotypic , chimeric , single chain antibodies , fragments , ( e . g . fab , f ( ab ) 2 , and fab expression library fragments , and epitope - binding fragments thereof )], polypeptides , nucleic acids , carbohydrates , and small organic or inorganic molecules . a substance or compound may be an endogenous physiological compound or it may be a natural or synthetic compound . modulation of a c2gnt3 polypeptide can be evaluated , for instance , by evaluating the inhibitory / stimulatory effect of an agent on c2gnt3 biological activity in comparison to a control or reference . the control or reference may be , e . g ., a predetermined reference value , or may be evaluated experimentally . for example , in a cell - based assay where a host cell expressing recombinant c2gnt3 is incubated in a medium containing a potential modulating agent , a control or reference may be , e . g ., a host cell incubated with an agent having a known effect on c2gnt3 expression / activity , a host cell incubated in the same medium without any agent , a host cell transfected with a “ mock ” vector not expressing any c2gnt3 polypeptide , or any other suitable control or reference . in a cell - free assay where c2gnt3 polypeptide is incubated in a medium containing a potential modulating agent , a control or reference may be , for example , medium not containing c2gnt3 polypeptide , medium not containing any agent , medium containing a reference polypeptide or agent , or any other suitable control or reference . substances which modulate a c2gnt3 polypeptide can be identified based on their ability to associate with a c2gnt3 polypeptide . therefore , the invention also provides methods for identifying substances that associate with a c2gnt3 polypeptide . substances identified using the methods of the invention may be isolated , cloned and sequenced using conventional techniques . a substance that associates with a polypeptide of the invention may be an agonist or antagonist of the biological or immunological activity of a polypeptide of the invention . the term “ agonist ” refers to a molecule that increases the amount of , or prolongs the duration of , the activity of the polypeptide . the term “ antagonist ” refers to a molecule which decreases the biological or immunological activity of the polypeptide . agonists and antagonists may include proteins , nucleic acids , carbohydrates , or any other molecules that associate with a polypeptide of the invention . substances which can associate with a c2gnt3 polypeptide may be identified by reacting a c2gnt3 polypeptide with a test substance which potentially associates with a c2gnt3 polypeptide , under conditions which permit the association , and removing and / or detecting the associated c2gnt3 polypeptide and substance . substance - polypeptide complexes , free substance , or non - complexed polypeptides may be assayed . conditions which permit the formation of substance - polypeptide complexes may be selected having regard to factors such as the nature and amounts of the substance and the polypeptide . the substance - polypeptide complex , free substance or non - complexes polypeptides may be isolated by conventional isolation techniques , for example , salting out , chromatography , electrophoresis , gel filtration , fractionation , absorption , polyacrylamide gel electrophoresis , agglutination , or combinations thereof . to facilitate the assay of the components , antibody against a polypeptide of the invention or the substance , or labelled polypeptide , or a labelled substance may be utilized . the antibodies , polypeptides , or substances may be labelled with a detectable substance as described above . a c2gnt3 polypeptide , or the substance used in the method of the invention may be insolubilized . for example , a polypeptide , or substance may be bound to a suitable carrier such as agarose , cellulose , dextran , sephadex , sepharose , carboxymethyl cellulose polystyrene , filter paper , ion - exchange resin , plastic film , plastic tube , glass beads , polyamine - methyl vinyl - ether - maleic acid copolymer , amino acid copolymer , ethylene - maleic acid copolymer , nylon , silk , etc . the carrier may be in the shape of , for example , a tube , test plate , beads , disc , sphere etc . the insolubilized polypeptide or substance may be prepared by reacting the material with a suitable insoluble carrier using known chemical or physical methods , for example , cyanogen bromide coupling . the invention also contemplates a method for evaluating a compound for its ability to modulate the biological activity of a polypeptide of the invention , by assaying for an agonist or antagonist ( i . e . enhancer or inhibitor ) of the association of the polypeptide with a substance which interacts with the polypeptide ( e . g . donor or acceptor substrates or parts thereof ). the basic method for evaluating if a compound is an agonist or antagonist of the association of a polypeptide of the invention and a substance that associates with the polypeptide is to prepare a reaction mixture containing the polypeptide and the substance under conditions which permit the formation of substance - polypeptide complexes , in the presence of a test compound . the test compound may be initially added to the mixture , or may be added subsequent to the addition of the polypeptide and substance . control reaction mixtures without the test compound or with a placebo are also prepared . the formation of complexes is detected and the formation of complexes in the control reaction but not in the reaction mixture indicates that the test compound interferes with the interaction of the polypeptide and substance . the reactions may be carried out in the liquid phase or the polypeptide , substance , or test compound may be immobilized as described herein . the agent can be selected from compounds , compositions , antibodies or antibody fragments , antisense sequences and ribozyme nucleotide sequences for c2gnt3 polypeptide . it will be understood that the agonists and antagonists i . e . inhibitors and enhancers , that can be assayed using the methods of the invention may act on one or more of the interaction sites an the polypeptide or substance including agonist binding sites , competitive antagonist binding cites , non - competitive antagonist binding sites or allosteric sites . the invention also makes it possible to screen for antagonists that inhibit the effects of an agonist of the interaction of a polypeptide of the invention with a substance which is capable of associating with the polypeptide . thus , the invention may be used to assay for a compound that competes for the same interacting site of a polypeptide of the invention . substances that modulate a c2gnt3 polypeptide of the invention can be identified based on their ability to interfere with or enhance the activity of a c2gnt3 polypeptide . therefore , the invention provides a method for evaluating a compound for its ability to modulate the activity of a c2gnt3 polypeptide comprising ( a ) reacting an acceptor substrate and a donor substrate for a c2gnt3 polypeptide in the presence of a test substance ; ( b ) measuring the amount of donor substrate transferred to acceptor substrate , and ( c ) carrying out steps ( a ) and ( b ) in the absence of the test substance to determine if the substance interferes with or enhances transfer of the sugar donor to the acceptor by the c2gnt3 polypeptide . suitable acceptor substrate for use in the methods of the invention are a saccharide , oligosaccharides , polysaccharides , polypeptides , glycopolypeptides , or glycolipids which are either synthetic with linkers at the reducing end or naturally occuring structures , for example , asialo - agalacto - fetuin glycopeptide . acceptors will generally comprise β - d - galactosyl - 1 , 3 - n - acetyl - d - galactosaminyl -. the donor substrate may be a nucleotide sugar , dolichol - phosphate - sugar or dolichol - pyrophosphate - oligosaccharide , for example , uridine diphospho - n - acetylglucosamine ( udp - glcnac ), or derivatives or analogs thereof . the c2gnt3 polypeptide may be obtained from natural sources or produced used recombinant methods as described herein . the acceptor or donor substrates may be labeled with a detectable substance as described herein , and the interaction of the polypeptide of the invention with the acceptor and donor will give rise to a detectable change . the detectable change may be colorimetric , photometric , radiometric , potentiometric , etc . the activity of c2gnt3 polypeptide of the invention may also be determined using methods based on hplc ( koenderman et al ., febs lett . 222 : 42 , 1987 ) or methods employed synthetic oligosaccharide acceptors attached to hydrophobic aglycones ( palcic et al glycoconjugate 5 : 49 , 1988 ; and pierce et al , biochem . biophys . res . comm . 146 : 679 , 1987 ). the c2gnt3 polypeptide is reacted with the acceptor and donor substrates at a ph and temperature effective for the polypeptide to transfer the donor to the acceptor , and where one of the components is labeled , to produce a detectable change . it is preferred to use a buffer with the acceptor and donor to maintain the ph within the ph range effective for the polypeptides . the buffer , acceptor and donor may be used as an assay composition . other compounds such as edta and detergents may be added to the assay composition . the reagents suitable for applying the methods of the invention to evaluate compounds that modulate a c2gnt3 polypeptide may be packaged into convenient kits providing the necessary materials packaged into suitable containers . the kits may also include suitable supports useful in performing the methods of the invention . substances that modulate a c2gnt3 polypeptide can also be identified by treating immortalized cells which express the polypeptide with a test substance , and comparing the morphology of the cells with the morphology of the cells in the absence of the substance and / or with immortalized cells which do not express the polypeptide . examples of immortalized cells that can be used include lung epithelial cell lines such as mvllu or hek293 ( human embryonal kidney ) transfected with a vector containing a nucleic acid of the invention . in the absence of an inhibitor the cells show signs of morphologic transformation ( e . g . fibroblastic morphology , spindle shape and pile up ; the cells are less adhesive to substratum ; there is less cell to cell contact in monolayer culture ; there is reduced growth - factor requirements for survival and proliferation ; the cells grow in soft - agar of other semi - solid medium ; there is a lack of contact inhibition and increased apoptosis in low - serum high density cultures ; there is enhanced cell motility , and there is invasion into extracellular matrix and secretion of proteases ). substances that inhibit one or more phenotypes may be considered an inhibitor . a substance that inhibits a c2gnt3 polypeptide may be identified by treating a cell which expresses the polypeptide with a test substance , and assaying for complex core 2 - based o - linked structures ( e . g . repeating gal [ β ] 1 - 4glcnac [ β ]) associated with the cell . the complex core 2 - based o - linked structures can be assayed using a . substance that binds to the structures ( e . g . antibodies ). cells that have not been treated with the substance or which do not express the polypeptide may be employed as controls . substances which inhibit transcription or translation of a c2gnt3 gene may be identified by transfecting a cell with an expression vector comprising a recombinant molecule of the invention , including a reporter gene , in the presence of a test substance and comparing the level of expression of the c2gnt3 polypeptide , or the expression of the polypeptide encoded by the reporter gene with a control cell transfected with the nucleic acid molecule in the absence of the substance . the method can be used to identify transcription and translation inhibitors of a c2gnt3 gene . the substances or compounds identified by the methods described herein , polypeptides , nucleic acid molecules , and antibodies of the invention may be used for modulating the biological activity of a c2gnt3 polypeptide , and they may be used in the treatment of conditions mediated by a c2gnt3 polypeptide . in particular , they may be used to t - cell development and lymphocyte homing and they may be used in the prevention and treatment of thymus - related disorders . therefore , the present invention may be useful for diagnosis or treatment of various thymus - related disorders in mammals , preferably humans . such disorders include the following : tumors and cancers , hypoactivity , hyperactivity , atrophy , enlargement of the thymus , and the like . other disorders include disregulation of t - lymphocyte selection or activity and would include but not be limited to disorders involving autoimmunity , arthritis , leukemias , lymphomas , immunosuppression , sepsis , wound healing , acute and chronic in action , cell mediated immunity , humor immunity , th1 / th2 imbalance , and the like . the substances or compounds identified by the methods described herein , antibodies , and polypeptides , and nucleic acid molecules of the invention may be useful in the prevention and treatment of tumors . tumor metastasis may be inhibited or prevented by inhibiting the adhesion of circulating cancer cells . the substances , compounds , etc . of the invention may be especially useful in the treatment of various forms of neoplasia such as leukemias , lymphomas , melanomas , adenomas , sarcomas , and carcinomas of solid tissues in patients . in particular the composition may be used for treating malignant melanoma , pancreatic cancer , cervico - uterine cancer , cancer of the liver , kidney , stomach , lung , rectum , breast , bowel , gastric , thyroid , neck , cervix , salivary gland , bile duct , pelvis , mediastinum , urethra , bronchogenic , bladder , esophagus and colon , and kaposi &# 39 ; s sarcoma which is a form of cancer associated with hiv - infected patients with acquired immune deficiency syndrome ( aids ). the substances etc . are particularly useful in the prevention and treatment of tumors of the immune system and thymus and the metastases derived from these tumors . a substance or compound identified in accordance with the methods described herein , antibodies , polypeptides , or nucleic acid molecules of the invention may be used to modulate t - cell activation and immunodeficiency due to the wiskott - aldrich syndrome or aids , or to stimulate hematopoietic progenitor cell growth , and / or confer protection against chemotherapy and radiation therapy in a subject . accordingly , the substances , antibodies , and compounds may be formulated into pharmaceutical compositions for administration to subjects in a biologically compatible form suitable for administration in vivo . by biologically compatible form suitable for administration in vivo is meant a form of the substance to be administered in which any toxic effects are outweighed by the therapeutic effects . the substances may be administered to living organisms including humans , and animals . administration of a therapeutically active amount of the pharmaceutical compositions of the present invention is defined as an amount effective , at dosages and for periods of time necessary to achieve the desired result . for example , a therapeutically active amount of a substance may vary according to factors such as the disease state , age , sex , and weight of the individual , and the ability of antibody to elicit a desired response in the individual . dosage regima may be adjusted to provide the optimum therapeutic response . for example , several divided doses may be administeted daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation . the active substance may be administered in a convenient manner such as by injection ( subcutaneous , intravenous , etc . ), oral administration , inhalation , transdermal application , or rectal administration . depending on the route of administration , the active substance may be coated in a material to protect the compound from the action of enzymes , acids and other natural conditions that may inactivate the compound . the compositions described herein can be prepared by methods known per se for the preparation of pharmaceutically acceptable compositions which can be administered to subjects , such that an effective quantity of the active substance is combined in a mixture with a pharmaceutically acceptable vehicle . suitable vehicles are described , for example , in remington &# 39 ; s pharmaceutical sciences ( remington &# 39 ; s pharmaceutical sciences , mack publishing company , easton , pa ., usa 1985 ). on this basis , the compositions include , albeit not exclusively , solutions of the substances or compounds in association with one or more pharmaceutically acceptable vehicles or diluents , and contained in buffered solutions with a suitable ph and iso - osmotic with the physiological fluids . after pharmaceutical compositions have been prepared , they can be placed in an appropriate container and labeled for treatment of an indicated condition . for administration of an inhibitor of a polypeptide of the invention , such labeling would include amount , frequency , and method of administration . the nucleic acids encoding c2gnt3 polypeptides or any fragment thereof , or antisense sequences may be used for therapeutic purposes . antisense to a nucleic acid molecule encoding a polypeptide of the invention may be med in situations to block the synthesis of the polypeptide . in particular , cells may be transformed with sequences complementary to nucleic acid molecules encoding c2gnt3 polypeptide . thus , antisense sequences may be used to modulate c2gnt3 activity or to achieve regulation of gene function . sense or antisense oligomers or larger fragments , can be designed from various locations along the coding or regulatory regions of sequences encoding a polypeptide of the invention . expression vectors may be derived from retroviruses , adenoviruses , herpes or vaccinia viruses or from various bacterial plasmids for delivery of nucleic acid sequences to the target organ , tissue , or cells . vectors that express antisense nucleic acid sequences of c2gnt3 polypeptide can be constructed using techniques well known to those skilled in the art ( see for example , sambrook , fritsch , maniatis , molecular cloning , a laboratory manual , second edition ( 1989 ) cold spring harbor laboratory press , cold spring harbor , n . y ). genes encoding c2cnt3 polypeptide can be turned off by transforming a cell or tissue with expression vectors that express high levels of a nucleic acid molecule or fragment thereof which encodes a polypeptide of the invention . such constructs may be used to introduce untranslatable sense or antisense sequences into a cell . even if they do not integrate into the dna , the vectors may continue to transcribe rna molecules until all copies are disabled by endogenous nucleases . transient expression may last for extended periods of time ( e . g . a month or more ) with a non - replicating vector or if appropriate replication elements are part of the vector system . modification of gene expression may be achieved by designing antisense molecules , dna , rna , or pna , to the control regions of a c2gnt3 polypeptide gene i . e . the promoters , enhancers , and introns . preferably the antisense molecules are oligonucleotides derived from the transcription initiation site ( e . g . between positions − 10 and + 10 from the start site ). inhibition can also be achieved by using triple - helix base - pairing techniques . triple helix pairing causes inhibition of the ability of the double helix to open sufficiently for the binding of polymerases , transcription factors , or regulatory molecules ( see gee j . e . et al ( 1994 ) in : huber , b . e . and b . i . carr , molecular and immunologic approaches , futura publishing co ., mt . kisco , n . y .). ribozymes , enzymatic rna molecules , may be used to catalyze the specific cleavage of rna . ribozyme action involves sequence - specific hybridization of the ribozyme molecule to complementary target rna , followed by endonucleolytic cleavage . for example , hammerhead motif ribozyme molecules may be engineered that can specifically and efficiently catalyze endonucleolytic cleavage of sequences encoding a polypeptide of the invention . specific ribosome cleavage sites within any rna target may be initially identified by scanning the target molecule for ribozyme cleavage sites which include the following sequences : gua , guu , and guc . short rna sequences of between 15 and 20 ribonucleotides corresponding to the region of the cleavage site of the target gene may be evaluated for secondary structural features which may render the oligonucleotide inoperable . the suitability of candidate targets may be evaluated by testing accessibility to hybridization with complementary oligonucleotides using ribonuclease protection assays . therapeutic efficacy and toxicity may be determined by standard pharmaceutical procedures in cell cultures or with experimental animals , such as by calculating the ed 50 ( the dose therapeutically effective in 50 % of the population ) or ld 50 ( the dose lethal to 50 % of the population ) statistics . the therapeutic index is the dose ratio of therapeutic to toxic effects and it can be expressed as the ed 50 / ld 50 ratio . pharmaceutical compositions which exhibit large therapeutic indices are preferred . the invention also provides methods for studying the function of a c2gnt3 polypeptide . cells , tissues , and non - human animals lacking in c2gnt3 expression or partially lacking in c2gnt3 expression may be developed using recombinant expression vectors of the invention having specific deletion or insertion mutations in a c2gnt3 gene . a recombinant expression vector may be used to inactivate or alter the endogenous gene by homologous recombination , and thereby create a c2gnt3 deficient cell , tissue or animal . null alleles may be generated in cells , such as embryonic stem cells by deletion mutation . a recombinant c2gnt3 gene may also be engineered to contain an insertion mutation which inactivates c2gnt3 . such a construct may then be introduced into a cell , such as an embryonic stem cell , by a technique such as transfection , elcctroporation , injection etc . cells lacking an intact c2gnt3 gene may then be identified , for example by southern blotting , northern blotting or by assaying for expression of a polypeptide of the invention using the methods described herein . such cells may then be used to generate transgenic non - human animals deficient in c2gnt3 . germline transmission of the mutation may be achieved , for example , by aggregating the embryonic stem cells with early stage embryos , such as 8 cell embryos , in vitro ; transferring the resulting blastocysts into recipient females and ; generating germline transmission of the resulting aggregation chimeras . such a mutant animal may be used to define specific cell populations , developmental patterns and in vivo processes , normally dependent on c2gnt3 expression . the invention thus provides a transgenic non - human mammal all of whose germ cells and somatic cells contain a recombinant expression vector that inactivates or alters a gene encoding a c2gnt3 polypeptide . further the invention provides a transgenic non - human mammal , which does not express a c2gnt3 polypeptide of the invention . a transgenic non - human animal includes but is not limited to mouse , rat , rabbit , sheep , hamster , guinea pig , micro - pig , pig , dog , cat , goat , and non - human primate , preferably mouse . the invention also provides a transgenic non - human animal assay system which provides a model system for testing for an agent that reduces or inhibits a pathology associated with a c2gnt3 polypeptide comprising : ( a ) administering the agent to a transgenic non - human animal of the invention ; and ( b ) determining whether said agent reduces or inhibits the pathology in the transgenic non - human animal relative to a transgenic non - human animal of step ( a ) to which the agent has not been administered . the agent may be useful to treat the disorders and conditions discussed herein . the agents may also be incorporated in a pharmaceutical composition as described herein . a polypeptide of the invention may be used to support the survival , growth , migration , and / or differentiation of cells expressing the polypeptide . thus , a polypeptide of the invention may be used as a supplement to support , for example cells in culture . the invention relates to a method for preparing an oligosaccharide comprising contacting a reaction mixture comprising an activated donor substrate e . g . glcnac , and an acceptor substrate in the presence of a polypeptide of the invention . examples of acceptor substrates for use in the method for preparing an oligosaccharide are a saccharide , oligosaccharides , polysaccharides , glycopeptides , glycopolypeptides , or glycolipids which are either synthetic with linkers at the reducing end or naturally occurring structures , for example , asialo - agalacto - fetuin glycopeptide . the activated donor substrate is preferably glcnac which may be part of a nucleotide - sugar , a dolichol - phosphate - sugar , or dolichol - pyrophosphate - oligosaccharide . in an embodiment of the invention , the oligosaccharides are prepared on a carrier that is non - toxic to a mammal , in particular a human such as a lipid isoprenoid or polyisoprenoid alcohol . an example of a suitable carrier is dolichol phosphate . the oligosaccharide may be attached to a carrier via a labile bond allowing for chemical removal of the oligosaccharide from the lipid carrier . in the alternative , the oligosaccharide transferase may be used to transfer the oligosaccharide from a lipid carrier to a polypeptide . the following examples are intended to further illustrate the invention without limiting its scope . a : identification of cdna homologous to c2gnt3 by analysis of gss database sequence information . database searches were performed with the coding sequence of the human c2 / 4gnt ( c2gnt2 ) sequence using the blastn and tblastn algorithms against the gss database at the national center for biotechnology information , usa . the blastn algorithm was used to identify gsss representing the query gene ( identities of ≧ 95 %), whereas tblastn was used to identify non - identical , but similar gss sequences . gsss with 50 - 90 % nucleotide sequence identity were regarded as different from the query sequence . composites of the sequence information for two gsss were compiled and analysed for sequence similarity to human c2 / 4gnt ( c2gnt2 ). a gss clone cit - hsp - 2288b17 . tf ( gss genbank accession number aq005888 ), derived from a putative homologue to c2 / 4gnt ( c2gnt2 ), was obtained from research genetics inc ., usa . sequencing of this clone revealed a partial open reading frame with significant sequence similarity to c2 / 4gnt ( c2gnt2 ). the coding region of human c2gnt - l ( c2gnt1 ), c2 / 4gnt ( c2gnt2 ) and a bovine homologue was previously found to be organized in one exon (( 22 ),( 15 )). since the 3 ′ sequence available from the c2gnt3 gss was incomplete but likely to be located in the single exon , the missing 3 ′ portion of the open reading frame was obtained by sequencing a genomic p1 clone . the p1 clone was obtained from a human foreskin genomic p1 library ( dupont merck pharmaceutical co . human foreskin fibroblast p1 library ) by screening with the primer pair : tshc96 ( 5 ′- ggtttcaccgtctccaacata - 3 ′, seq id no : 3 ) and tshc101 ( 5 ′- tcgtaaggcacctgatactt - 3 ′, seq id no : 6 ). one genomic clone for c2gnt3 , gs22597 # 844 / b1 was obtained from genome systems inc ., usa . dna from p1 phage was prepared as recommended by genome systems inc . the entire coding sequence of the c2gnt3 gene was represented in the clone and sequenced in full using automated sequencing ( abi377 , perkin - elmer ). confirmatory sequencing was performed on a cdna clone obtained by pcr ( 30 cycles at 95 ° c . for 10 sec ; 55 ° c . for 15 sec and 68 ° c . for 2 min 30 sec ) on cdna from human thymus poly a - mrna with the sense primer : the composite sequence contained an open reading frame of 1359 base pairs encoding a putative protein of 453 amino acids with type ii domain structure predicted by the tmpred - algorithm at the swiss institute for experimental cancer research ( isrec ). ( http :// www . ch . embnet . org / software / tmpred_form . html ). an expression vector construct designed to encode amino acid residues 39 - 453 of c2gnt3 was prepared by pcr using p1 dna , and the primer pair : tshc100 ( 5 ′- cgaggatccgcaaaaagacatttacttggtt - 3 ′, seq id no : 5 ) and tshc121 ( 5 ′- agcgaattcttactatcatgatgtggtagtg - 3 ′, seq id no : 9 ) with bamh1 and ecori restriction sites , respectively ( fig2 ). the pcr product was cloned between the bamhi and ecori sites of pacgp67a ( pharmingen ), and the insert was fully sequenced . pacgp67 - c2gnt3 - sol was co - transfected with baculo - gold ™ dna ( pharmingen ) as described previously ( 23 ). recombinant baculo - viruses were obtained after two successive amplifications in sf9 cells grown in serum - containing medium , and titers of virus were estimated by titration in 24 - well plates with monitoring of enzyme activities . transfection of sf9 - cells with pacgp67 - c2gnt3 - sol resulted in marked increase in glcnac - transferase activity compared to uninfected cells or cells infected with a control construct . standard assays were performed using culture supernatant from infected cells in 50 μl reaction mixtures containing 100 mm mes ( ph 6 . 5 ), 0 . 1 % nonidet p - 40 , 150 μm udp -[ 14 c ]- glcnac ( 2 , 000 cpm / nmol ) ( amersham pharmacia biotech ), and the indicated concentrations of acceptor substrates ( sigma and toronto research laboratories ltd ., see table i for structures ). reaction products were quantified by chromatography on dowex agi - x8 . a human rna master blot ( clontech ) was used for expression analysis . the cdna - fragment of soluble c2gnt3 was used as a probe for hybridization . the probe was random primer - labeled using [ α 32 p ] datp and and the strip - ez dna labeling kit ( ambion ). the membrane was probed for 6 h at 65 ° c . following the protocol of the manufacturer ( clontech ) and washed five times for 20 min each at 65 ° c . with 2 × ssc , 1 % sds and twice for 20 min each at 55 ° c . with 0 . 1 × ssc , 0 . 5 % sds . a human multiple tissue northern blot mtn ii ( clontech ), was probed as described ( 24 ), and washed twice for 10 min each at room temperature with 2 × ssc , 0 . 1 % sds ; twice for 10 min each at 55 ° c . with 1 × ssc , 0 . 1 % sds ; and once for 10 min with 0 . 1 × ssc , 0 . 1 % sds at 55 ° c . pcr analysis of c2gnt3 expression in resting and activated human blood cell fractions was performed using the primer pair : tshc118 ( 5 ′- gagtcagtgtggaattgaatac - 3 ′, seq id no : 7 ) and tshc126 ( 5 ′- caacagtctcctcaaccctg - 3 ′, seq id no : 11 ). pcr amplifications with primers specific for human c2gnt3 ( c2gnt3 ) or gapdh ( g3pdh , supplied by the manufacturer ) were performed on a normalized human blood cell cdna panel ( mtc from clontech ) for 31 cycles . expression of c2gnt3 transcript was detected in all peripheral blood mononuclear cell ( pbmc ) fractions with particularly high levels of expression in cd4 and cd8 positive t - lymphocytes ( fig4 ). tshc123 ( 5 ′- gggcagcatttgcctagtatg - 3 ′, seq id no : 10 ) and tshc119 ( 5 ′- gatctctgatttggctcagtg - 3 ′, seq id no : 8 ) as described in fig5 have been used for pcr amplification of individual sequences of the coding exon . each pcr product was subcloned and the sequence of 10 clones containing the appropriate insert was determined assuring that both alleles of each individual are characterized . polymorphism of the amplified dna can be analyzed using , e . g ., dna sequencing , single - strand conformational polymorphism ( sscp ) or mismatch mutation . from the foregoing it will be evident that , although specific embodiments of the invention have been described herein for purposes of illustration , various modifications may be made without deviating from the spirit and scope of the invention . 1 . clausen , h . and bennett , e . p . a family of udp - galnac : polypeptide n - acetylgalactosaminyltransferases control the initiation of mucin - type o - linked glycosylation . glycobiology 6 : 635 - 646 , 1996 . 2 . piller , f ., piller , v ., fox , r . i ., and fukuda , m . human t - lymphocyte activation is associated with changes in o - glycan biosynthesis . j . biol . chem . 263 : 15146 - 15150 , 1988 . 3 . yang , j . m ., byrd , j . c ., siddiki , b . b ., chung , y . s ., okuno , m ., sowa , m ., kim , y . s ., matta , k . l ., and brockhausen , i . alterations of o - glycan biosynthesis in human colon cancer tissues . glycobiology 4 : 873 - 884 , 1994 . 4 . yousefi , s ., higgins , e ., daoling , z ., pollex - kruger , a ., hindsgaul , o ., and dennis , j . w . increased udp - glcnac : gal beta 1 - 3galnac - r ( glcnac to galnac ) beta - 1 , 6 - n - acetylglucosaminyltransferase activity in metastatic murine tumor cell lines . control of polylactosamine synthesis . j . biol . chem . 266 : 1772 - 1782 , 1991 . 5 . fukuda , m . possible roles of tumor - associated carbohydrate antigens . cancer res . 56 : 2237 - 2244 , 1996 . 6 . brockhausen , i ., yang , j . m ., burchell , j ., whitehouse , c ., and taylor - papadimitriou , j . mechanisms underlying aberrant glycosylation of muci mucin in breast cancer cells . eur . j . biochem . 233 : 607 - 617 , 1995 . 7 . brockhausen , i ., kuhns , w ., schachter , h ., matta , k . l ., sutherland , d . r ., and baker , m . a . biosynthesis of o - glycans in leukocytes from normal donors and from patients with leukemia : increase in o - glycan core 2 udp - glcnac : gal beta 3 galnac alpha - r ( glcnac to galnac ) beta ( 1 - 6 )- n - acetylglucosaminyltransferase in leukemic cells . cancer res . 51 : 1257 - 1263 , 1991 . 8 . higgins , e . a ., siminovitch , k . a ., zhuang , d . l ., brockhausen , i ., and dennis , j . w . aberrant o - linked oligosaccharide biosynthesis in lymphocytes and platelets from patients with the wiskott - aldrich syndrome . j . biol . chem . 266 : 6280 - 6290 , 1991 . 9 . saitoh , o ., piller , f ., fox , r . i ., and fukuda , m . t - lymphocytic leukemia expresses complex , branched o - linked oligosaccharides on a major sialoglycoprotein , leukosialin . blood 77 : 1491 - 1499 , 1991 . 10 . springer , g . f . t and tn , general carcinoma autoantigens . science 224 : 1198 - 1206 , 1984 . 11 . kumar , r ., camphausen , r . t ., sullivan , f . x ., and cumming , d . a . core2 beta - 1 , 6 - n - acetylglucosaminyltransferase enzyme activity is critical for p - selectin glycoprotein ligand - 1 binding to p - selectin . blood 88 : 3872 - 3879 , 1996 . 12 . williams , d . and schachter , h . mucin synthesis . i . detection in canine submaxillary glands of an n - acetylglucosaminyltransferase which acts on mucin substrates . j . biol . chem . 255 : 11247 - 11252 , 1980 . 13 . bierhuizen , m . f . and fukuda , m . expression cloning of a cdna encoding udp - glcnac : gal beta 1 - 3 - galnac - r ( glcnac to galnac ) beta 1 - 6glcnac transferase by gene transfer into cho cells expressing polyoma large tumor antigen . proc . natl . acad . sci . u . s . a . 89 : 9326 - 9330 , 1992 . 14 . schwientek , t ., yeh , j . c ., levery , s . b ., keck , b ., merkx , g ., van kessel , a . g ., fukuda , m ., and clausen , h . control of o - glycan branch formation . molecular cloning and characterization of a novel thymus - associated core 2 beta1 , 6 - n - acetylglucosaminyltransferase . j . biol . chem . 275 : 11106 - 11113 , 2000 . 15 . schwientek , t ., nomoto , m ., levery , s . b ., merkx , g ., van kessel , a . g ., bennett , e . p ., hollingsworth , m . a ., and clausen , h . control of o - glycan branch formation . molecular cloning of human cdna encoding a novel beta1 , 6 - n - acetylglucosaminyl - transferase forming core 2 and core 4 . j . biol . chem . 274 : 4504 - 4512 , 1999 . 16 . yeh , j . c ., ong , e ., and fukuda , m . molecular cloning and expression of a novel beta - 1 , 6 - n - acetylglucosaminyltransferase that forms core 2 , core 4 , and i branches . j . biol . chem . 274 : 3215 - 3221 , 1999 . 17 . baum , l . g ., pang , m ., perillo , n . l ., wu , t ., delegeane , a ., uittenbogaart , c . h ., fukuda , m ., and seilhamer , j . j . human thymic epithelial cells express an endogenous lectin , galectin - 1 , which binds to core 2 o - glycans on thymocytes and t lymphoblastoid cells . j . exp . med . 181 : 877 - 887 , 1995 . 18 . perillo , n . l ., marcus , m . e ., and baum , l . g . galectins : versatile modulators of cell adhesion , cell proliferation , and cell death . j . mol . med . 76 : 402 - 412 , 1998 . 19 . perillo , n . l ., pace , k . e ., seilhamer , j . j ., and baum , l . g . apoptosis of t cells mediated by galectin - 1 . nature 378 : 736 - 739 , 1995 . 20 . devereux , j ., haeberli , p ., and smithies , o . a comprehensive set of sequence analysis programs for the vax . nucleic acids res . 12 : 387 - 395 , 1984 21 . altschul , s . f ., gish , w ., miller , w ., myers , e . w ., and lipman , d . j . basic local alignment search tool . j . mol . biol . 1990 , oct . 5 ., 215 : 403 - 410 , 22 . bierhuizen , m . f ., maemura , k ., kudo , s ., and fukuda , m . genomic organization of core 2 and i branching beta - 1 , 6 - n - acetylglucosaminyltransferases . implication for evolution of the beta - 1 , 6 - n - acetylglucosaminyltransferase gene family . glycobiology 5 : 417 - 425 , 1995 . 23 . almeida , r ., amado , m ., david , l ., levery , s . b ., holmes , e . h ., merkx , g ., van kessel , a . g ., rygaard , e ., hassan , h ., bennett , e ., and clausen , h . a family of human beta4 - galactosyltransferases . cloning and expression of two novel udp - galactose : beta - n - acetylglucosamine beta1 , 4 - galactosyltransferases , beta4gal - t2 and beta4gal - t3 . j . biol . chem . 272 : 31979 - 31991 , 1997 . 24 . bennett , e . p ., hassan , h ., and clausen , h . cdna cloning and expression of a novel human udp - n - acetyl - alpha - d - galactosamine . polypeptide n - acetylgalactosaminyltransferase , galnac - t3 . j . biol . chem . 271 : 17006 - 17012 , 1996 . 25 . wandall , h . h ., hassan , h ., mirgorodskaya , e ., kristensen , a . k ., roepstorff , p ., bennett , e . p ., nielsen , p . a ., hollingsworth , m . a ., burchell , j ., taylor - papadimitriou , j ., and clausen , h . substrate specificities of three members of the human udp - n - acetyl - alpha - d - galactosamine : polypeptide n - acetylgalactosaminyltransferase family , galnac - t1 , - t2 , and - t3 . j . biol . chem . 272 : 23503 - 23514 , 1997 . 26 . matteucci , m . d . and caruthers , m . h . j . am . chem . soc . 103 : 3185 - 3191 . 1981 . 27 . yoo , y ., rote , k ., and rechsteiner , m . synthesis of peptides as cloned ubiquitin extensions . j . biol . chem . 264 : 17078 - 17083 , 1989 . met lys ile phe lys cys tyr phe lys his thr leu gln gln lys val asn val arg arg leu phe pro gln lys asp ile tyr leu val glu tyr ser leu ser thr ser pro phe val arg asn arg tyr thr his val lys asp glu val arg tyr glu val asn cys ser gly ile tyr glu gln glu tyr gln thr leu arg gly 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ala gly glu asn pro ser ser asp ile asn cys thr lys val leu gln lys phe lys lys arg pro arg trp thr pro asp asp tyr ile asn met thr ser asp cys ser ser phe ile lys arg arg lys tyr ile val glu val his his lys ile glu met leu asp arg leu leu arg ala ile tyr met pro gln asn phe tyr cys val his val asp thr lys ser glu asp ser tyr leu ala ala val met gly ile ala ser cys phe ser asn val val gln ala asp leu asn cys met lys asp leu tyr ala met ser ala asn trp lys tyr leu ile asn leu cys gly met asp phe pro ile lys asn leu glu thr glu arg met pro ser his lys glu glu arg trp lys lys met leu pro pro leu glu thr pro leu phe ser gly ser ala tyr phe val val ser arg glu tyr val gly tyr val leu gln asn glu lys ile gln lys leu met glu trp ala gln asp thr tyr ser pro asp glu tyr leu trp ala thr ile gln arg ile pro glu val pro gly ser leu pro ala ser his lys tyr asp leu ser asp met gln ala val ala arg phe val lys trp gln tyr phe glu gly asp val ser lys gly ala pro tyr pro pro cys asp gly val his val arg 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a novel gene defining a novel human udp - glcnac : galβ1 - 3galnaca β1 , 6glcnac - transferase , termed c2gnt3 , with unique enzymatic properties is disclosed . the enzymatic activity of c2gnt3 is shown to be distinct from that of previously identified enzymes of this gene family . the invention discloses isolated dna molecules and dna constructs encoding c2gnt3 and derivatives thereof by way of amino acid deletion , substitution or insertion exhibiting c2gnt3 activity , as well as cloning and expression vectors including such dna , cells transfected with the vectors , and recombinant methods for providing c2gnt3 . the enzyme c2gnt3 and c2gnt3 - active derivatives thereof are disclosed , in particular soluble derivatives comprising the catalytically active domain of c2gnt3 . further , the invention discloses methods of obtaining 1 , 6 - n - acetylglucosaminyl glycosylated saccharides , glycopeptides or glycoproteins by use of an enzymically active c2gnt3 protein or fusion protein thereof or by using cells stably transfected with a vector including dna encoding an enzymatically active c2gnt3 protein as an expression system for recombinant production of such glycopeptides or glycoproteins . methods are disclosed for the identification of agents with the ability to inhibit or stimulate the biological activity of c2gnt3 . furthermore , methods of using c2gnt3 in the structure - based design of inhibitors or stimulators thereof are also disclosed in the invention . also a method for the identification of dna sequence variations in the c2gnt3 gene by isolating dna from a patient , amplifying c2gnt3 - coding exons by pcr , and detecting the presence of dna sequence variation , are disclosed .