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Host factor Hfq of Escherichia coli stimulates elongation of poly(A) tails by poly(A) polymerase I

E Hajnsdorf1, P Régnier

  • 1Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.

Proceedings of the National Academy of Sciences of the United States of America
|March 4, 2000
PubMed

Insights

Host factor Hfq regulates bacterial mRNA poly(A) tail length by stimulating poly(A) polymerase I. This finding reveals a conserved mechanism for polyadenylation in prokaryotes and eukaryotes.

Area of Science:

  • Molecular Biology
  • Bacterial Genetics
  • RNA Metabolism

Background:

  • Bacterial mRNA poly(A) tail length is determined by a balance between polyadenylation and degradation.
  • Host factor Hfq's role in poly(A) tail metabolism was previously uncharacterized.

Purpose of the Study:

  • To investigate the involvement of host factor Hfq in bacterial mRNA poly(A) tail metabolism.
  • To elucidate the mechanism by which Hfq influences polyadenylation.

Main Methods:

  • In vivo studies involving inactivation of the hfq gene and analysis of rpsO mRNA poly(A) tail length.
  • In vitro experiments using poly(A) polymerase I and Hfq to assess polyadenylation activity.
  • Investigating the binding properties of Hfq to oligoadenylated RNA.

Main Results:

  • Inactivation of the hfq gene led to shorter poly(A) tails on rpsO mRNA.
  • Hfq significantly stimulated the synthesis of long poly(A) tails by poly(A) polymerase I in vitro.
  • Hfq demonstrated strong binding to RNA with existing poly(A) tails (20-35 nucleotides), promoting processive polyadenylation.

Conclusions:

  • Host factor Hfq plays a crucial role in regulating bacterial mRNA poly(A) tail length.
  • Hfq enhances poly(A) tail elongation by stimulating poly(A) polymerase I activity.
  • The findings suggest conserved mechanisms for poly(A) tail synthesis control in both prokaryotes and eukaryotes, similar to mammalian poly(A) binding protein II (PABPII).

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