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A novel sRNA component of the carbon storage regulatory system of Escherichia coli
Author(s) -
Weilbacher Thomas,
Suzuki Kazushi,
Dubey Ashok K.,
Wang Xin,
Gudapaty Seshigirao,
Morozov Igor,
Baker Carol S.,
Georgellis Dimitris,
Babitzke Paul,
Romeo Tony
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03459.x
Subject(s) - biology , regulator , escherichia coli , small rna , transfer rna , psychological repression , rna , microbiology and biotechnology , regulation of gene expression , rna binding protein , genetics , gene , gene expression
Summary Small untranslated RNAs (sRNAs) perform a variety of important functions in bacteria. The 245 nucleotide sRNA of Escherichia coli , CsrC, was discovered using a genetic screen for factors that regulate glycogen biosynthesis. CsrC RNA binds multiple copies of CsrA, a protein that post‐transcriptionally regulates central carbon flux, biofilm formation and motility in E. coli . CsrC antagonizes the regulatory effects of CsrA, presumably by sequestering this protein. The discovery of CsrC is intriguing, in that a similar sRNA, CsrB, performs essentially the same function. Both sRNAs possess similar imperfect repeat sequences (18 in CsrB, nine in CsrC), primarily localized in the loops of predicted hairpins, which may serve as CsrA binding elements. Transcription of csrC increases as the culture approaches the stationary phase of growth and is indirectly activated by CsrA via the response regulator UvrY. Because CsrB and CsrC antagonize CsrA activity and depend on CsrA for their synthesis, a csrB null mutation causes a modest compensatory increase in CsrC levels and vice versa. Homologues of csrC are apparent in several Enterobacteriaceae. The regulatory and evolutionary implications of these findings are discussed.