Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic <i>rac</i> Prophage of <i>Escherichia coli</i> K-12.

ABSTRACT: Horizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. The cryptic rac prophage in Escherichia coli K-12 carries the gene for a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality of racR in E. coli K-12 is attributed to its role in transcriptionally repressing toxin gene(s) called ydaS and ydaT, which are adjacent to and coded divergently to racR. IMPORTANCE Transcription factors in the bacterium E. coli are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in E. coli, we realized that the protein RacR, a putative t

SUBMITTER: Krishnamurthi R 

PROVIDER: S-EPMC5700373 | biostudies-literature | 2017 Nov-Dec

REPOSITORIES: biostudies-literature