title: Reduced Protein Synthesis Fidelity Inhibits Flagellar Biosynthesis and Motility.
abstract: Accurate translation of the genetic information from DNA to protein is maintained by multiple quality control steps from bacteria to mammals. Genetic and environmental alterations have been shown to compromise translational quality control and reduce fidelity during protein synthesis. The physiological impact of increased translational errors is not fully understood. While generally considered harmful, translational errors have recently been shown to benefit cells under certain stress conditions. In this work, we describe a novel regulatory pathway in which reduced translational fidelity downregulates expression of flagellar genes and suppresses bacterial motility. Electron microscopy imaging shows that the error-prone Escherichia coli strain lacks mature flagella. Further genetic analyses reveal that translational errors upregulate expression of a small RNA DsrA through enhancing its transcription, and deleting DsrA from the error-prone strain restores motility. DsrA regulates expression of H-NS and RpoS, both of which regulate flagellar genes. We demonstrate that an increased level of DsrA in the error-prone strain suppresses motility through the H-NS pathway. Our work suggests that bacteria are capable of switching on and off the flagellar system by altering translational fidelity, which may serve as a previously unknown mechanism to improve fitness in response to environmental cues.
authors.affiliation: Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Evans
authors.affiliation: Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.|Graduate School of Biomedical Sciences, Houston, TX 77030, USA.
authors.forename: Jiqiang
authors.initials: J
authors.lastname: Ling
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000378:metabolism; D036781:Fimbriae Proteins / Q000378:metabolism; D005407:Flagella / Q000235:genetics / Q000378:metabolism*; D008854:Microscopy, Electron; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D058727:RNA, Small Untranslated / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C405431:DsrA RNA, E coli; D029968:Escherichia coli Proteins; C529458:FimG protein, E coli; D058727:RNA, Small Untranslated; D012808:Sigma Factor; D015534:Trans-Activators; C090553:flhD protein, E coli; C069567:sigma factor KatF protein, Bacteria; D036781:Fimbriae Proteins