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Induction of the immunoprotective coat of Yersinia pestis at body temperature is mediated by the Caf1R transcription factor

Lookup NU author(s): Majeed Al-Jawdah, Dr Iglika Ivanova, Dr Helen Waller, Professor Neil Perkins, Professor Jeremy Lakey, Dr Daniel Peters

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

© 2019 The Author(s). Background: Thermal regulation of gene expression occurs in many microorganisms, and is mediated via several typical mechanisms. Yersinia pestis is the causative agent of the plague and spreads by zoonotic transfer from fleas to mammalian blood with a concomitant rapid temperature change, from ambient to 37 °C, which induces the expression of capsular antigen (Caf1) that inhibits phagocytosis. Caf1 is formed into long polymeric fimbriae by a periplasmic chaperone (Caf1M) and outer membrane usher (Caf1A). All three are encoded on an operon regulated by an AraC-type transcription factor Caf1R. The aim of this study was to determine the role of Caf1R in the thermal control of caf1 operon gene expression. Results: PCR analysis of cDNA demonstrated that the genes of the operon are transcribed as a single polycistronic mRNA. Bioinformatic analysis, supported by deletion mutagenesis, then revealed a region containing the promoter of this polycistronic transcript that was critical for Caf1 protein expression. Caf1R was found to be essential for Caf1 protein production. Finally, RT-PCR analysis and western blot experiments showed large, Caf1R dependent increases in caf1 operon transcripts upon a shift in temperature from 25 °C to 35 °C. Conclusions: The results show that thermal control of Caf1 polymer production is established at the transcriptional level, in a Caf1R dependent manner. This gives us new insights into how a virulent pathogen evades destruction by the immune system by detecting and responding to environmental changes.


Publication metadata

Author(s): Al-Jawdah AD, Ivanova IG, Waller H, Perkins ND, Lakey JH, Peters DT

Publication type: Article

Publication status: Published

Journal: BMC Microbiology

Year: 2019

Volume: 19

Issue: 1

Online publication date: 29/03/2019

Acceptance date: 25/03/2019

ISSN (electronic): 1471-2180

Publisher: BioMed Central Ltd.

URL: https://doi.org/10.1186/s12866-019-1444-4

DOI: 10.1186/s12866-019-1444-4

PubMed id: 30922226


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