Krishnamurthi, Revathy ORCID: 0000-0002-9351-5032, Ghosh, Swagatha, Khedkar, Supriya and Seshasayee, Aswin Sai Narain
(2017)
Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic <i>rac</i> Prophage of <i>Escherichia coli</i> K-12.
MSPHERE, 2 (6).
e00392-e00317.
Text
Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic rac Prophage of Escherichia coli K-12..pdf - Published version Download (1MB) | Preview |
Abstract
Horizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. The cryptic <i>rac</i> prophage in <i>Escherichia coli</i> K-12 carries the gene for a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality of <i>racR</i> in <i>E. coli</i> K-12 is attributed to its role in transcriptionally repressing toxin gene(s) called <i>ydaS</i> and <i>ydaT</i>, which are adjacent to and coded divergently to <i>racR</i>. <b>IMPORTANCE</b> Transcription factors in the bacterium <i>E. coli</i> are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in <i>E. coli</i>, we realized that the protein RacR, a putative transcription factor encoded by a gene on the <i>rac</i> prophage, is an essential protein. Here, using genetics, biochemistry, and bioinformatics, we show that its essentiality derives from its role as a transcriptional repressor of the <i>ydaS</i> and <i>ydaT</i> genes, whose products are toxic to the cell. Unlike type II toxin-antitoxin systems in which transcriptional regulation involves complexes of the toxin and antitoxin, repression by RacR is sufficient to keep <i>ydaS</i> transcriptionally silent.
Item Type: | Article |
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Uncontrolled Keywords: | prophages, toxin-antitoxin, transcriptional repressor |
Divisions: | Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences |
Depositing User: | Symplectic Admin |
Date Deposited: | 28 Jun 2022 08:56 |
Last Modified: | 05 Feb 2024 19:01 |
DOI: | 10.1128/mSphere.00392-17 |
Related URLs: | |
URI: | https://livrepository.liverpool.ac.uk/id/eprint/3157340 |