[Effect of nucleotide replacement on the effectiveness and specificity of the SP6 promotor]

The interaction of SP6 RNA-polymerase with its promoter (sequence; see text) where +1 is the initiation site, was investigated. The substitution of C for A at +2 position and T for A at +3 creates the AluI-site (-2-1+1+2). The efficiency of the promoter changed in this way is comparable with that of the natural one. The introduced restriction site permits to insert the gene precisely at the initiation site and the synthesis of the transcripts with the authentic 5'-ends. The influence of the nucleotide substitution within -5-10 region of SP6-promoter on its interaction with SP6 and T7 RNA-polymerases was investigated. A new promoter, able to initiate the transcription with both SP6 and T7 RNA polymerases, was obtained.