All 4 bases of both strands at -9 and -8 in T7 promoter are needed to be substituted by SP6-specific bases to switch promoter specificity.
It has previously been shown that a substitution of two base pairs at -9 and -8 in T7 promoter by SP6 promoter-specific base pairs alone is sufficient to make the T7 variant become an SP6 promoter, abolishing T7 promoter activity [Lee, S. S., and Kang, C. (1992) Biochem. Int. 26, 1-5]. In order to determine which of the 4 bases on both strands at the two positions is involved in the discriminative specificity, each base or each pair of bases was substituted by SP6-specific base(s), allowing one or two mismatches. The results show that all-four-base substitution only is capable of switching promoter specificity, and that all the four bases are substantially involved in T7 promoter activity.
Lee
S S
SS
Department of Life Science, Korea Advanced Institute of Science and Technology, Taejon.
Park
S K
SK
Cho
I H
IH
Kang
C
C
D017123:Bacteriophage T7 / Q000235:genetics*; D001435:Bacteriophages / Q000235:genetics*; D001482:Base Composition / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000378:metabolism; D014644:Genetic Variation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
D004279:DNA, Viral; D012321:DNA-Directed RNA Polymerases