The interplay of Hfq, poly(A) polymerase I and exoribonucleases at the 3' ends of RNAs resulting from Rho-independent termination: A tentative model

RNA Biol. 2013 Apr;10(4):602-9. doi: 10.4161/rna.23664. Epub 2013 Feb 7.

Abstract

Discovered in eukaryotes as a modification essential for mRNA function, polyadenylation was then identified as a means used by all cells to destabilize RNA. In Escherichia coli, most accessible 3' RNA extremities are believed to be potential targets of poly(A) polymerase I. However, some RNAs might be preferentially adenylated. After a short statement of the current knowledge of poly(A) metabolism, we discuss how Hfq could affect recognition and polyadenylation of RNA terminated by Rho-independent terminators. Comparison of RNA terminus leads to the proposal that RNAs harboring 3' terminal features required for Hfq binding are not polyadenylated, whereas those lacking these structural elements can gain the oligo(A) tails that initiate exonucleolytic degradation. We also speculate that Hfq stimulates the synthesis of longer tails that could be used as Hfq-binding sites involved in non-characterized functions of Hfq-dependent sRNAs.

Keywords: RNA degradation; Rho-independent terminators; exoribonucleases; oligo(A) tails; poly(A) polymerase; polyadenylation; protein Hfq.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Escherichia coli / chemistry*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Exoribonucleases / chemistry*
  • Exoribonucleases / genetics
  • Exoribonucleases / metabolism*
  • Gene Expression Regulation, Bacterial
  • Host Factor 1 Protein / chemistry*
  • Host Factor 1 Protein / genetics
  • Host Factor 1 Protein / metabolism
  • Poly A / chemistry
  • Poly A / genetics
  • Poly A / metabolism*
  • Polyadenylation*
  • RNA Stability*
  • RNA, Messenger / chemistry
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • RNA, Small Untranslated / chemistry*
  • RNA, Small Untranslated / genetics
  • RNA, Small Untranslated / metabolism
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / genetics*
  • Repressor Proteins / chemistry
  • Repressor Proteins / metabolism*
  • Rho Factor / genetics
  • Sequence Alignment

Substances

  • Bacterial Proteins
  • Escherichia coli Proteins
  • Host Factor 1 Protein
  • PapI protein, E coli
  • RNA, Messenger
  • RNA, Small Untranslated
  • RNA-Binding Proteins
  • Repressor Proteins
  • Rho Factor
  • Poly A
  • Exoribonucleases