EFFECT ON DNA-TRANSCRIPTION OF NUCLEOTIDE-SEQUENCES UPSTREAM TO T7 PROMOTER

The T7 RNA polymerase-dependent transcription was studied as a functio n of nucleotide sequence structures positioned upstream of the T7 prom oter. Model double-stranded DNA templates were constructed for this pu rpose. They contained a target sequence of 485 base pairs (cDNA fragme nt of Venesuelian encephalomyelitis equine virus genome), T7 promoter consensus and different extra base sequences upstream of the T7 promot er. The level of the target sequence transcription was clearly determi ned by the extra base sequence. The presence of one extra base pair G . C ensured the most pronounced effect, transcription was increased on e order of magnitude in comparison with template which has only a cano nical T7 promoter sequence at the 5'-end.