AUTHOR=Fernández-Fernández Rocío , Hernández Sara B. , Puerta-Fernández Elena , Sánchez-Romero María A. , Urdaneta Verónica , Casadesús Josep 

TITLE=Evidence for Involvement of the Salmonella enterica Z-Ring Assembly Factors ZapA and ZapB in Resistance to Bile

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.647305

DOI=10.3389/fmicb.2021.647305

ISSN=1664-302X

ABSTRACT=<p>Genes annotated as <italic>ygfE</italic> and <italic>yiiU</italic> in the genome of <italic>Salmonella enterica</italic> serovar Typhimurium encode proteins homologous to <italic>Escherichia coli</italic> cell division factors ZapA and ZapB, respectively. ZapA<sup>−</sup> and ZapB<sup>−</sup> mutants of <italic>S. enterica</italic> are bile-sensitive. The amount of <italic>zapB</italic> mRNA increases in the presence of a sublethal concentration of sodium deoxycholate (DOC) while <italic>zapA</italic> mRNA remains unaffected. Increased <italic>zapB</italic> mRNA level in the presence of DOC is not caused by upregulation of <italic>zapB</italic> transcription but by increased stability of <italic>zapB</italic> mRNA. This increase is suppressed by an <italic>hfq</italic> mutation, suggesting the involvement of a small regulatory RNA. We provide evidence that such sRNA is MicA. The ZapB protein is degraded in the presence of DOC, and degradation appears to involve the Lon protease. We propose that increased stability of <italic>zapB</italic> mRNA in the presence of DOC may counter degradation of bile-damaged ZapB, thereby providing sufficient level of functional ZapB protein to permit Z-ring assembly in the presence of bile.</p>