An unexpected abundance of bidirectional promoters within Salmonella Typhimurium plasmids

Abstract

Transcription of the DNA template, to generate an RNA message, is the first step in gene expression. The process initiates at DNA sequences called promoters. Conventionally, promoters have been considered to drive transcription in a specific direction. However, in recent work, we showed that many prokaryotic promoters can drive divergent transcription. This is a consequence of key DNA sequences for transcription initiation being inherently symmetrical. Here, we used global transcription start site mapping to determine the prevalence of such bidirectional promoters in Salmonella Typhimurium. Surprisingly, bidirectional promoters occur three times more frequently in plasmid components of the genome compared to chromosomal DNA. Implications for the evolution of promoter sequences are discussed.

Mapping direct and indirect MarA/SoxS/Rob/RamA regulons in Salmonella Typhimurium reveals repression of csgD and biofilm formation

“…As a control, we used cappable-seq data for S . Typhimurium SL1344 carrying empty pAMNF (E-MTAB-12506) [30].…”

“…Sequence reads are accessible in ArrayExpress (accession number E-MTAB-12628). As a control, we used cappable-seq data for S. Typhimurium SL1344 carrying empty pAMNF (E-MTAB-12506) [30].…”

Microbial Musings: Spring 2023

“…Back-to-back papers from Middlemiss and colleagues [18, 19] revealing the complexity of gene expression (and its regulation) in Salmonella .…”