9419784 Reznikoff This research uses Escherichia coli sigma 70 RNA polymerase and lactose (lac) operon promoter model system to study positive gene regulation by catabolite activator protein CAP. CAP is thought to activate transcription by direct interaction with RNA polymerase. One consequence of this interaction may be to stimulate an interaction between RNA polymerase and specific upstream DNA sequences. The role of candidate (-40 region) DNA sequences in the CAP activation of the lac promoter will be investigated through chemical interference and site-specific mutation studies. In addition, the possible limiting effect of these upstream sequences on lacP expression in the absence of CAP will be examined. %%% The first event in gene expression is the initiation of RNA synthesis or transcription. This multistep process involves the interaction of the enzyme RNA polymerase with specific DNA sequences called promoters. The promoter DNA sequence determines the start site and frequency of unregulated RNA synthesis. This research will investigate in detail how the bacterial regulatory protein CAP facilitates the specific interaction of RNA polymerase with the bacterial promoter lac to activate transcription of the lac genes. This CAP-lac system is a general model for understanding transcriptional activator proteins, which have been known to regulate gene expression for over 25 years. ***
