A novel sRNA component of the carbon storage regulatory system of Escherichia coli

Authors

  • Thomas Weilbacher,

    1. Department of Molecular Biology and Immunology, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107-2699, USA.
    Search for more papers by this author
  • Kazushi Suzuki,

    1. Department of Microbiology and Immunology, Emory University School of Medicine, 3133 Rollins Research Center, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
    Search for more papers by this author
  • Ashok K. Dubey,

    1. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
    Search for more papers by this author
  • Xin Wang,

    1. Department of Microbiology and Immunology, Emory University School of Medicine, 3133 Rollins Research Center, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
    Search for more papers by this author
  • Seshigirao Gudapaty,

    1. Department of Molecular Biology and Immunology, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107-2699, USA.
    Search for more papers by this author
      Biochemistry Department, Andhra University, Visakhapatnam 530-003, India.
  • Igor Morozov,

    1. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
    Search for more papers by this author
      ‡Plant Science and Fungal Molecular Biology Research Group, School of Biological Sciences, Donnan Laboratories, The University of Liverpool, Liverpool L69 7ZD, UK.
  • Carol S. Baker,

    1. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
    Search for more papers by this author
  • Dimitris Georgellis,

    1. Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico.
    Search for more papers by this author
  • Paul Babitzke,

    1. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
    Search for more papers by this author
  • Tony Romeo

    Corresponding author
    1. Department of Microbiology and Immunology, Emory University School of Medicine, 3133 Rollins Research Center, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
    Search for more papers by this author

  • Present addresses: Biochemistry Department, Andhra University, Visakhapatnam 530-003, India. Plant Science and Fungal Molecular Biology Research Group, School of Biological Sciences, Donnan Laboratories, The University of Liverpool, Liverpool L69 7ZD, UK.

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.

Ancillary