In:
Molecular Microbiology, Wiley, Vol. 116, No. 3 ( 2021-09), p. 877-889
Abstract:
When subcloned into low‐copy‐number expression vectors, rumAB , encoding polV R391 (RumA′ 2 B), is best characterized as a potent mutator giving rise to high levels of spontaneous mutagenesis in vivo . This is in dramatic contrast to the poorly mutable phenotype when polV R391 is expressed from the native 88.5 kb R391, suggesting that R391 expresses cis ‐acting factors that suppress the expression and/or the activity of polV R391 . Indeed, we recently discovered that SetR R391 , an ortholog of λ cI repressor, is a transcriptional repressor of rumAB . Here, we report that CroS R391 , an ortholog of λ Cro, also serves as a potent transcriptional repressor of rumAB . Levels of RumA are dependent upon an interplay between SetR R391 and CroS R391 , with the greatest reduction of RumA protein levels observed in the absence of SetR R391 and the presence of CroS R391 . Under these conditions, CroS R391 completely abolishes the high levels of mutagenesis promoted by polV R391 expressed from low‐copy‐number plasmids. Furthermore, deletion of croS R391 on the native R391 results in a dramatic increase in mutagenesis, indicating that CroS R391 plays a major role in suppressing polV R391 mutagenesis in vivo . Inactivating mutations in CroS R391 therefore have the distinct possibility of increasing cellular mutagenesis that could lead to the evolution of antibiotic resistance of pathogenic bacteria harboring R391.
Type of Medium:
Online Resource
ISSN:
0950-382X
,
1365-2958
Language:
English
Publisher:
Wiley
Publication Date:
2021
detail.hit.zdb_id:
1501537-3
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