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A novel CsrA titration mechanism regulates fimbrial gene expression in Salmonella typhimurium
Author(s) -
Sterzenbach Torsten,
Nguyen Kim T,
Nuccio SeanPaul,
Winter Maria G,
Vakulskas Christopher A,
Clegg Steven,
Romeo Tony,
Bäumler Andreas J
Publication year - 2013
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2013.206
Subject(s) - biology , untranslated region , operon , fimbria , plasmid , gene , gene expression , three prime untranslated region , messenger rna , ribosomal binding site , rna , post transcriptional regulation , regulation of gene expression , microbiology and biotechnology , genetics , ribosome , escherichia coli
A hierarchical control of fimbrial gene expression limits laboratory grown cultures of Salmonella enterica serovar typhimurium ( S. typhimurium ) to the production of type I fimbriae encoded by the fimAICDHF operon. Here we show that an unlikely culprit, namely the 5′‐untranslated region (5′‐UTR) of a messenger (m)RNA, coordinated the regulation. Binding of CsrA to the 5′‐UTR of the pefACDEF transcript was required for expression of plasmid‐encoded fimbriae. The 5′‐UTR of the fimAICDHF transcript cooperated with two small untranslated RNAs, termed CsrB and CsrC, in antagonizing the activity of the RNA binding protein CsrA. Through this post‐transcriptional mechanism, the 5′‐UTR of the fimAICDHF transcript prevented production of PefA, the major structural subunit of plasmid‐encoded fimbriae. This regulatory mechanism limits the costly expression of plasmid‐encoded fimbriae to host environments in a mouse model. Collectively, our data suggest that the 5′‐UTR of an mRNA coordinates a hierarchical control of fimbrial gene expression in S. typhimurium .