Figure 2

Analysis of polymerase expression by SDS-PAGE. Cells containing autogene constructs were grown to an O.D₆₀₀ of 0.4 and induced with IPTG. Aliquots of cells were lysed at time points following induction, and separated on SDS-PAGE. Bands were visualized using Coomassie blue. Arrows indicate the relative position of T7 RNA polymerase. The normalization of samples is apparent from the amount of E. coli proteins present in each lane. (a) Comparison of the activities of the Q758C polymerase on a mutant promoter (GACG at positions -11 to -8) and the wild-type promoter (GACT at positions -11 through -8). (b) Comparison of the activities of the R3-17 polymerase with three different promoters (GGTA, TATA, and TGTA at positions -11 through -8) and the activity of the wild-type autogene with its promoter (GACT at positions -11 through -8).