The bacterial chromosome is dynamic. The principle goal of my research is to understand how DNA topology is altered by transcription in Salmonella enterica serovar Typhimurium LT2. Gamma delta-resolution requires two direct repeat Res sites to pair a plectonemic synapse. Previous work from our lab showed that the zones of high transcription inhibited gamma delta-resolution. Using phage λ recombineering methods, we have developed Salmonella strains to study ribosomal RNA operons, which are the most highly transcribed genes in bacteria. We propose a molecular model for how supercoiling generated by high levels of transcription modifies chromosome structure
