The Effects of Mutant T7 Promoter on Transcriptions

To determine key bases on T7 promoter recognized by T7 RNA polymerase and eukaryotic RNA polymerase, the base located at - 11 of the promoter was replaced with other bases and the mutant promoters were inserted upstream of coding sequences of CAT gene. CAT test in vivo and Slot - Blot test in vitro showed that the promoter could not be transcripted by both T7 RNA polymerase and eukaryotic RNA polymerase II. The result suggests that the - 11 base might be the key base for T7 RNA polymerase and eukaryotic RNA polymerase II systems.