while this invention is susceptible of embodiment in many different forms , there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated . as disclosed in fig1 a , the transgene of the present invention contains three parts : 5 &# 39 ; hs2 from the human beta globin lcr , sheep β c promoter , and hgh gene . the transgene of the present invention embodies the nucleotide sequence , seq id no : 1 , disclosed in fig1 b . the transgene was originally constructed in vector pbs . the dna fragment containing the sheep β c gene is a 3 . 2 kb hind iii fragment obtained from a plasmid clone available from j . lingrel , university of cincinnati ; genbank accession no . x 14728 . the sequence for sheep β c is disclosed in garner and lingrel . ( 1989 ) j . mol . evol . 28 : 175 - 184 which is incorporated herein by reference in its entirety . this fragment contains the entire β c gene with 827 bp of 5 &# 39 ; flanking sequence and 791 bp of 3 &# 39 ; flanking sequence . the β c promoter is contained in an 819 bp hindiii - pvuii fragment . the β c promoter and a small amount of puc18 vector flanking sequence was purified as a 908 bp dna fragment . apai linkers were blunt - end ligated to this and the fragment was digested with apai . as disclosed in fig1 a , the linkered β c promoter fragment was ligated to the unique apai site in the proximal promoter of the hgh gene . the hgh gene , carried in plasmid pghgh2 . 6 - 3 , was supplied by h . goodman , mass . general hospital . ( see also genbank accession nos . j00148 and k00612 ) the sequence of hgh gene is disclosed in denoto et al . ( 1981 ) nucl . acids res . 9 : 3719 - 3730 which is also incorporated herein by reference in its entirety . the total length of the promoter used in the transgene construct of the present invention is 842 bp . of this the β c promoter contributed 819 bp to the promoter with the balance of the promoter sequence derived from hgh gene itself and the apai linker . the cap site and all downstream sequences were derived entirely from the hgh gene . a 1 . 9 kb hindiii fragment containing the 5 &# 39 ; hs2 element of the human beta globin lcr was inserted into the hindiii site immediately upstream of the β c promoter to complete the construct . the 5 &# 39 ; hs2 hindiii fragment is defined as nucleotides 1527 through 3451 in genbank file humhbb - part 3 . the transgene of the present invention was purified from vector sequence before microinjection into mouse embryos . no vector sequence was microinjected . after the dna was purified free of vector sequences and concentrated using elutip columns ( schleicher and schuell , inc .) the purified and concentrated dna was microinjected into male or female pronuclei of fertilized one - cell mouse eggs using techniques known in the art . dna is microinjected at a concentration of 2 ng / μl in 10 mm tris ( ph 7 . 5 ), 0 . 1 mm edta . the injected eggs were then implanted into pseudopregnant female mice following the procedures disclosed in hogan , et al . ( 1986 cold spring harbor lab .) manipulating the mouse embryo , a laboratory manual . the eggs in the foster females were allowed to develop to term , usually 20 - 21 days . mice were obtained from the jackson laboratory . embryos for microinjection were produced by breeding b6sjl / f 1 j mice . genomic dna was purified from tail tissue and transgenic individuals were determined by slot blot hybridization . transgene integrity was confirmed by genomic southern blot hybridization . six hs2 + β c hgh transgenic lines were produced by breeding founder mice ( tg407 , tg409 , tg416 , tg420 , tg435 , tg450 ). the tg420 tg435 and tg450 lines were the primary focus of analysis . expression of the hgh transgene was analyzed in blood by the quantitative rnase protection assay at key developmental time points . rna was prepared for rnase protection assay by collecting blood samples from embryos and fetuses by first dissecting individuals from the uterus in their amniotic sacs , rinsing in cold phosphate - buffered saline ( pbs ; 0 . 8 % nacl , 2 . 7 mm kcl , 1 . 5 mm kh 2 po 4 , 20 mm na 2 hpo 2 ) containing 10 units / ml of heparin , and then bleeding each individual from the amnion into fresh cold pbs - heparin . blood was collected from very young mice into cold pbs - heparin following decapitation . older mice were bled from the tail vein . fig2 discloses the results of rnase protection assay using five 5 - 6 month old mice referred to in fig2 as a through e . endogenous alpha globin provided the internal standard in each sample . in fig2 the ratio of hgh to alpha globin in the baseline sample is compared to the ratio of hgh to alpha globin in the treated sample to indicate fold induction of the hgh gene . as disclosed in fig2 the tg420 line was able to up - regulate expression of the transgene in response to phenylhydrazine - induced anemia and epo . the tg420 line increased expression of hgh mrna four to eight - fold with phenylhydrazine and three to twenty - fold with epo induction . the tg435 line induced expression two to 14 - fold with these treatments . this suggests that the 819 bp β c promoter fragment that was used contains an &# 34 ; epo - response element .&# 34 ; it presently is unknown in the art what exact dna sequence comprises an &# 34 ; epo response element &# 34 ; or how epo acts through it to induce expression of a gene . the most dramatic physiological characteristics of the hs2 + β c hgh transgenic mice is that the mice in three of the lines tg420 , tg450 , and tg435 grow 5 % to 40 % larger than normal . representative plots of transgenic and nontransgenic littermate growth rates are shown in fig3 a through 3c . although the mice produce their highest levels of hgh mrna as embryos and fetuses , their enhanced growth does not become apparent until approximately 3 weeks of age . this is most likely due to the absence of gh receptors in the liver preventing full expression of growth hormone &# 39 ; s systematic effects via igf production ( maes et al ., 1983 , endocrinology 113 : 1325 - 1332 ). the same growth trend was reported for mt - gh ( metallothionein - growth hormone ) transgenic mice ( hammer et al ., 1985 , cold spring harbor symp . ouant . biol . 50 : 379 - 387 ). the mice of three other transgenic lines ( tg407 , tg409 and tg416 ) express the β c hgh transgene at lower levels and do not grow large . quantitation of their serum hgh levels and comparison to the measurements already made reveal the threshold amount of systemic hgh that produces a growth response . radioimmunoassay ( ria ) was used to measure hgh levels in the serum and trapped within the red blood cells ( rbcs ) of the mice . efforts focused on the two lines showing the most obvious enhanced growth ( tg450 and tg420 ). in these lines hgh levels are approximately 5 - 10 times greater inside the rbcs than in the serum of tg450 mice and 50 - 100 times greater in rbcs than serum for tg420 mice ( volumetric comparisons ), indicating that most of the hgh is probably never released systemically . although it is difficult to compare directly between rias run in different labs using different tracers , it appears that serum levels of hgh are low in our mouse lines when compared to the mt - gh transgenic mice ( palmiter et al ., 1982 , nature 300 : 611 - 615 ). for example , some representative serum hgh values from tg420 mice were 270 ng / ml at 23 days , 110 ng / ml at 13 weeks , and 59 ng / ml at 5 months . this compares to values of 280 , 310 , 3 . 2 × 10 4 , 5 . 7 × 10 4 , 1 . 1 × 10 5 ng / ml in palmiter &# 39 ; s mice ( ages not specified ). to evaluate tissue specificity of transgene expression in these mice , in situ hybridization studies were conducted . ten micron sagittal sections of tg and control mouse fetuses were mounted onto nitrocellulose filters and probed with 35 s - labeled antisense hgh or a globin probes . the hgh mrna specific probe was hybridized to sagittal sections 18 . 5 gestational day ( nearly full - term ) mouse fetuses representing the three lines that demonstrated enhanced growth . adjacent sections were probed for mouse a globin mrna to identify erythroid tissues and pooled blood . representative control and transgenic sections are shown in fig4 . fetal liver was hybridized by both a globin and hgh probes indicating expression of both genes in the tissue . liver is the major erythropoietic organ at this age . pooled blood produces an a globin signal in the hearts of both tg and nontg fetuses . by the same token , high hgh mrna , also present in the blood , is detected in the heart of the tg fetus . the large arrow in fig4 indicates the hybridization signal in liver and the small arrow indicates the heart . transgenic fetuses from the tg420 , tg435 and tg450 lines produced the same results . transgenic mice from the tg420 and tg450 lines had spines that from simple observation were unquestionably longer than their littermate controls . to confirm this observation , the bones of both anesthetized live mice and eviscerated carcasses were measured and visualized radiographically by mammography according to the method disclosed in schneider et al ., ( 1994 ) j . bone min . res . 9 : 581 - 591 which is incorporated herein in its entirety . the development of the vertebrae and knees were monitored from birth through maturity in these two lines and the tg435 line . fig5 a is a radiographic image of representative caudal vertebrae and fig5 b is a graph of relative densities of these vertebrae over time . tg420 and tg450 transgenics have greater bone density than nontransgenics starting around three weeks . the relative difference in density increases with age , despite the extremely how levels of hgh typically measured in the serum of mature transgenics . for more detailed evaluation of differences due to transgene expression , histological specimens were collected and prepared following the methods disclosed in schneider , et al .,( 1988 ) j . bone min . res . 3 : 225 - 232 which is incorporated in its entirety herein by reference . cortical bone thickness was measured in some of the oldest members of the mouse colony . semi - thin sections were prepared from transgenic and age and sex - matched control mice . a representative comparison of cortical bone between an age and sex - matched control mouse is shown in fig6 a at the top and a 13 month male from the tg450 line is shown in fig6 a bottom . as disclosed in fig6 b , at 13 and 18 months cortical bone was significantly thicker in the tg450 line . the transgene of the present invention has produced dramatic bone development in certain transgenic mice , increasing the thickness and density of the bone . the enhanced bone deposition continues into advanced maturity in the mice , without increasing hgh mrna in the red blood cells and serum hormone levels in older animals . in many instances , serum hgh levels were within the normal ranges for endogenous mouse growth hormone . application of this same delivery mechanism for hgh to humans at risk or suffering from osteoporosis and other osteopenias may improve their bone deposition to resorption ratio . currently , the most effective treatments for osteoporosis are based on prevention and early warning for those who are especially at risk . the efficacies of current prescriptions such as estrogen , calcium , vitamin supplements , and weight - bearing exercise are sharply reduced when initiated late in life or after menopause . gene therapies using the transgene of the present invention would utilize the steps of ; collecting a patient &# 39 ; s erythroid stem cells from their bone marrow or circulation , the collected stem cells are transfected with an hgh gene construct such as the transgene of the present invention , and the transfected stem cells are retransfused into the patient . they home naturally to the bone marrow compartment in all its locations throughout the body to repopulate the marrow . individuals identified to be at risk prenatally , e . g . osteogenesis imperfecta patients , could be treated with stem cells isolated from cord blood as well . similar gene therapies may be employed in elderly patients who have already experienced fractures or are at serious risk . likewise , children or young adults with osteopenias or those predisposed to the development of osteopenias could also be treated with transfected erythroid stem cells . the osteopenias include primary osteoporosis such as involutional ( postmenopausal and senile ) and juvenile osteoporosis and secondary osteoporosis such as those included in table i below : table i______________________________________secondary osteoporosis ( osteopenias ) ______________________________________a . endocrine 1 . andrenal cortex cushing &# 39 ; s disease addison &# 39 ; s disease 2 . gonadal disorders hypogonadism 3 . pituitary acromegaly hypopituitarism 4 . pancreasdiabetes mellitus 5 . thyroid hyperthyroidism hypothyroidism 6 . parathyroid hyperparathyroidismb . marrow replacement and expansion 1 . myeloma 2 . leukemia 3 . metastatic disease 4 . gauchr &# 39 ; s disease 5 . amemias ( sickle cell , thalassemia ) c . drugs and substances 1 . corticosteroids 2 . heparin 3 . anticonvulsants 4 . immunosuppressants 5 . alcohold . chronic disease 1 . chronic renal disease 2 . hepatic insufficiency 3 . gi malasorption 4 . chronic inflammatory polyarthropathies 5 . chronic debility / immobilizatione . deficiency states 1 . vitamin d 2 . vitamin c ( scurvy ) 3 . calcium 4 . malnutritionf . inborn errors of metabolism 1 . osteogenesis imperfecta 2 . homocystinuria______________________________________ therapies using the transgene of the present invention could limit the risk of overuse or unnecessarily high systemic levels of gh . plasmid containing the hs2 + β c hgh transgene have been deposited with the american type culture collection on oct . 13 , 1994 and given atcc accession no . 75908 . while the specific embodiments have been illustrated and described , numerous modifications come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the scope of the accompanying claims . __________________________________________________________________________ # sequence listing - - - - ( 1 ) general information : - - ( iii ) number of sequences : 1 - - - - ( 2 ) information for seq id no : 1 : - - ( i ) sequence characteristics : ( a ) length : 4456 bp ( b ) type : nucleic acid ( c ) strandedness : single ( d ) topology : linear - - ( xi ) sequence description : seq id no : 1 : - - aagcttcagt ttttccttag ttcctgttac atttctgtgt gtctccatta gt -# gacctccc 60 - - atagtccaag catgagcagt tctggccagg cccctgtcgg ggtcagtgcc cc -# acccccgc 120 - - cttctggttc tgtgtaacct tctaagcaaa ccttctggct caagcacagc aa -# tgctgagt 180 - - catgatgagt catgctgagg cttagggtgt gtgcccagat gttctcagcc ta -# gagtgatg 240 - - actcctatct gggtccccag caggatgctt acagggcaga tggcaaaaaa aa -# ggagaagc 300 - - tgaccacctg actaaaactc cacctcaaac ggcatcataa agaaaatgga tg -# cctgagac 360 - - agaatgtgac atattctaga atatattatt tcctgaatat atatatatat at -# atatacac 420 - - atatacgtat atatatatat atatatatat ttgttgttat caattgccat ag -# aatgatta 480 - - gttattgtga atcaaatatt tatcttgcag gtggcctcta tacctagaag cg -# gcagaatc 540 - - aggctttatt aatacatgtg tatagatttt taggatctat acacatgtat ta -# atatgaaa 600 - - caaggatatg gaagaggaag gcatgaaaac aggaaaagaa aacaaacctt gt -# ttgccatt 660 - - ttaaggcacc cctggacagc taggtggcaa aaggcctgtg ctgttagagg ac -# acatgctc 720 - - acatacgggg tcagatctga cttggggtgc tactgggaag ctctcatctt aa -# ggatacat 780 - - ctcaggccag tcttggtgca ttaggaagat gtaggcaact ctgatcctga ga -# ggaaagaa 840 - - acattcctcc aggagagcta aaagggttca cctgtgtggg taactgtgaa gg -# actacaag 900 - - aggatgaaaa acaatgacag acagacataa tgcttgtggg agaaaaaaca gg -# aggtcaag 960 - - gggatagaga aggcttccag aagaatggct ttgaagctgg cttctgtagg ag -# ttcacagt 1020 - - ggcaaagatg tttcagaaat gtgacatgac ttaaggaact atacaaaaag ga -# acaaattt 1080 - - aaggagaggc agataaatta gttcaacaga catgcaagga attttcagat ga -# atgttatg 1140 - - tctccactga gcttcttgag gttagcagct gtgagggttt tgcaggccca gg -# acccatta 1200 - - caggacctca cgtatacttg acactgtttt ttgtattcat ttgtgaatga at -# gacctctt 1260 - - gtcagtctac tcggtttcgc tgtgaatgaa tgatgtcttg tcagcctact tg -# gtttcgct 1320 - - aagagcacag agagaagatt tagtgatgct atgtaaaaac ttcctttttg gt -# tcaagtgt 1380 - - atgtttgtga tagaaatgaa gacaggctac atgatgcata tctaacataa ac -# acaaacat 1440 - - taagaaagga aatcaacctg aagagtattt atacagataa caaaatacag ag -# agtgagtt 1500 - - aaatgtgtaa taactgtggc acaggctgga atatgagcca tttaaatcac aa -# attaatta 1560 - - gaaaaaaaac agtggggaaa aaattccatg gatgggtcta gaaagactag ca -# ttgtttta 1620 - - ggttgagtgg cagtgtttaa agggtgatat cagactaaac ttgaaatatg tg -# gctaaata 1680 - - actagaatac tctttatttt ttcgtatcat gaatagcaga tatagcttga tg -# gccccatg 1740 - - cttggtttaa catccttgct gttcctgaca tgaaatcctt aatttttgac aa -# aggggcta 1800 - - ttcattttca ttttatattg ggcctagaaa ttatgtagat ggtcctgagg aa -# aagtttat 1860 - - agcttgtcta tttctctctc taacatagtt gtcagcacaa tgcctaggct at -# aggaagta 1920 - - ctcaaagctt ctctgttctt ccagacactt tcacaggtca gtccatgagg aa -# acaaatta 1980 - - tatgccttga tttagtcttt gaacacattg cctctctcag ggttactgaa ac -# tttggggt 2040 - - tatgattgaa tttttactta tttgtatttc ttactacatg gagaggtctc ta -# cgttttca 2100 - - catatggatt aatggagtaa gtatttcaca ggatctctca atccacactt at -# tctatttt 2160 - - tctatcatta ttcatttggt cgtaaattaa attaagaaaa aattgaatga gt -# agataagt 2220 - - aaatgaatat ttgttttcat accagaatga cttaatccca aacaggcgaa ca -# aaagagat 2280 - - gcatatttag aacagaggca gaagttttat ccatggtgtc cttgtaattc tt -# ttgcatat 2340 - - tctgaaggca caggaggtga tccatccaca tagtcttaag ttgaatcata gt -# gtacaaat 2400 - - cctttccact ttctggagcc cagattctta atttgtgtta taaaaaaatt ga -# ggaagtgt 2460 - - tttccaagag attacctcgt tgagattcta aaatctctac aagcaaactt gc -# taaggaag 2520 - - atgattttag tagcaatgtg tattgctgga atgactgaga ccttgagatg cc -# cagaaaga 2580 - - gggctgacgg tctcaagtca gtaccaggaa gaccaaggag aagtatgact at -# catcattc 2640 - - aagcctcacc ctgtggaacc acaacttgga atgagccaat ctgctcacag aa -# gcagggag 2700 - - ggcaggaggc agggctgggc ataaaaggaa gagccgggcc agggggccca ca -# agagaccg 2760 - - gctcaaggat cccaaggccc aactccccga accactcagg gtcctgtgga cg -# ctcaccta 2820 - - gctgcaatgg ctacaggtaa gcgcccctaa aatccctttg ggcacaatgt gt -# cctgaggg 2880 - - gagaggcagc gacctgtaga tgggacgggg gcactaaccc tcaggtttgg gg -# cttctgaa 2940 - - tgagtatcgc catgtaagcc cagtatggcc aatctcagaa agctcctggt cc -# ctggaggg 3000 - - atggagagag aaaaacaaac agctcctgga gcagggagag tgctggcctc tt -# gctctccg 3060 - - gctccctctg ttgccctctg gtttctcccc aggctcccgg acgtccctgc tc -# ctggcttt 3120 - - tggcctgctc tgcctgccct ggcttcaaga gggcagtgcc ttcccaacca tt -# cccttatc 3180 - - caggcttttt gacaacgcta gtctccgcgc ccatcgtctg caccagctgg cc -# tttgacac 3240 - - ctaccaggag tttgtaagct cttggggaat gggtgcgcat caggggtggc ag -# gaaggggt 3300 - - gactttcccc cgctgggaaa taagaggagg agactaagga gctcagggtt tt -# tcccgaag 3360 - - cgaaaatgca ggcagatgag cacacgctga gtgaggttcc cagaaaagta ac -# aatgggag 3420 - - ctggtctcca gcgtagacct tggtgggcgg tccttctcct aggaagaagc ct -# atatccca 3480 - - aaggaacaga agtattcatt cctgcagaac ccccagacct ccctctgttt ct -# cagagtct 3540 - - attccgacac cctccaacag ggaggaaaca caacagaaat ccgtgagtgg at -# gccttgac 3600 - - cccaggcggg gatgggggag acctgtagtc agagcccccg ggcagcacag gc -# caatgccc 3660 - - gtccttcccc tgcagaacct agagctgctc cgcatctccc tgctgctcat cc -# agtcgtgg 3720 - - ctggagcccg tgcagttcct caggagtgtc ttcgccaaca gcctggtgta cg -# gcgcctct 3780 - - gacagcaacg tctatgacct cctaaaggac ctagaggaag gcatccaaac gc -# tgatgggg 3840 - - gtgggggtgg cgctaggggt ccccaatctt ggagccccac tgactttgag ag -# ctgtgtta 3900 - - gagaaacact gctgccctct ttttagcagt ccaggccctg acccaagaga ac -# tcacctta 3960 - - ttcttcattt cccctcgtga atcctctagc ctttctctac accctgaagg gg -# agggagga 4020 - - aaatgaatga atgagaaagg gagggagcag tacccaagcg cttggcctct cc -# ttctcttc 4080 - - cttcactttg cagaggctgg aagatggcag cccccggact gggcagatct tc -# aagcagac 4140 - - ctacagcaag ttcgacacaa actcacacaa cgatgacgca ctactcaaga ac -# tacgggct 4200 - - gctctactgc ttcaggaagg acatggacaa ggtcgagaca ttcctgcgca tc -# gtgcagtg 4260 - - ccgctctgtg gagggcagct gtggcttcta gctgcccggg tggcatccct gt -# gacccctc 4320 - - cccagtgcct ctcctggcct tggaagttgc cactccagtg cccaccagcc tt -# gtcctaat 4380 - - aaaattaagt tgcatcattt tgtctgacta ggtgtcctct ataatattat gg -# ggtggagg 4440 - - ggggtggttt ggagca - # - #- # 4456__________________________________________________________________________
an erythropoietin - inducible , erythroid - specific dna construct is disclosed . the dna construct comprises a promoter sequence from a sheep juvenile beta globin gene , an erythroid - specific enhancer sequence from the locus control region of the human beta globin gene and a nucleotide coding sequence of interest .