Selective Promoter Recognition by Chlamydial [sigma]28 Holoenzymev[white triangle down],[dagger]

The ... transcription factor confers the promoter recognition specificity of RNA polymerase (RNAP) in eubacteria. Chlamydia trachomatis has three known sigma factors, ... We developed two methods to facilitate the characterization of promoter sequences recognized by C. trachomatis ... One involved the arabinose-induced expression of plasmid-encoded ... in a strain of Escherichia coli defective in the ... structural gene, fliA. The second was an analysis of transcription in vitro with a hybrid holoenzyme reconstituted with E. coli RNAP core and recombinant ... These approaches were used to investigate the interactions of ... with the ...-dependent hctB promoter and selected E. coli (...)-dependent promoters, in parallel, compared with the promoter recognition properties of ... Our results indicate that RNAP containing ... has at least three characteristics: (i) it is capable of recognizing some but not all ...-dependent promoters; (ii) it can distinguish different promoter structures, preferentially activating promoters with upstream AT-rich sequences; and (iii) it possesses a greater flexibility than ... in recognizing variants with different spacing lengths separating the -35 and -10 elements of the core promoter. (ProQuest Information and Learning: ... denotes formulae/symbols omitted.)