it was found that ( i ) modifications of the nucleotide sequence , apart from the commonly accepted promoter region , both upstream and downstream of the rna initiation point greatly influenced the efficiency of promoters in vivo , ( ii ) a recombinant dna composed of one of the promoter-probe plasmids and a tandem of a1 , a2 , and a3 promoters of t7 bacteriophage dna induced a reproducible secondary change in plasmid dna upon cloning .
C0012854
dna
C0000702
a