DNA methylation‐dependent regulation of Pef expression in Salmonella typhimurium

摘要: Plasmid-encoded fimbriae (Pef) expressed by Salmonella typhimurium mediate adhesion to mouse intestinal epithelium. The pef operon shares features with the Escherichia coli pyelonephritis-associated pilus (pap) operon, which is under methylation-dependent transcriptional regulation. These include conserved DNA GATC box sites in upstream regulatory region as well homologues of PapI and PapB proteins. Unlike Pap fimbriae, are a variety laboratory media, Pef were only acidic, rich broth standing culture conditions. Analysis S. grown these conditions indicated that production was regulated phase variation mechanism, bacterial population skewed between fimbrial expression (phase ON) non-expression OFF) states. Leucine-responsive protein (Lrp) adenine methylase (Dam) required for transcription. In contrast, histone-like (H-NS) stationary-phase sigma factor (RpoS) repressed Methylation II site appeared be based on analysis GCTC mutant did not express fimbriae. methylation states that, acidic growth conditions, induced production, most I non-methylated, whereas X predominantly methylated. protection at dependent upon Lrp modulated PefI. Together, results indicate methylation, first example gene regulation outside E. coli.