Modified promoter for rna polymerase, its preparation and its

Abstract

An oligonucleotide is intended to be used as a promoter non-template strand in the transcription of a sequence of a nucleotide target in the presence of a phage RNA polymerase. The phage RNA polymerase has specific natural promoters containing a consensus sequence from at least position -17 to position -1. The oligonucleotide contains a core sequence flanked at at least one of its ends by a nucleotide sequence capable of hybridization with a sequence of the target. The core sequence contains a sequence of 6 to 9 consecutive nucleotides from the region -12 to -4 of the non-template strand of the specific promoter, or a sufficiently homologous sequence to enable the functionality of the RNA polymerase to be retained. One flanking sequence is complementary to a first region of the target, and a second flanking sequence, when present, is complementary to a second region of the target, the first and second regions being separated on the target by a sequence having a number of nucleotides equal to the number of nucleotides in the core sequence. The number of nucleotides in the flanking region, or the sum of the number of nucleotides in the flanking regions, is at least sufficiently high for the nucleotide to be able to hybridize with the target at the temperature of use of the RNA polymerase. Such an oligonucleotide enables transcription to be initiated at a site of the target which is not normally a transcription start site for the RNA polymerase.