Bacteriophage T4 polynucleotide kinase triggers degradation of mRNAs

Proc Natl Acad Sci U S A. 2012 May 1;109(18):7073-8. doi: 10.1073/pnas.1119802109. Epub 2012 Apr 12.


The bacteriophage T4-encoded RegB endoribonuclease is produced during the early stage of phage development and targets mostly (but not exclusively) the Shine-Dalgarno sequences of early genes. In this work, we show that the degradation of RegB-cleaved mRNAs depends on a functional T4 polynucleotide kinase/phosphatase (PNK). The 5'-OH produced by RegB cleavage is phosphorylated by the kinase activity of PNK. This modification allows host RNases G and E, with activity that is strongly stimulated by 5'-monophosphate termini, to attack mRNAs from the 5'-end, causing their destabilization. The PNK-dependent pathway of degradation becomes effective 5 min postinfection, consistent with our finding that several minutes are required for PNK to accumulate after infection. Our work emphasizes the importance of the nature of the 5' terminus for mRNA stability and depicts a pathway of mRNA degradation with 5'- to 3'-polarity in cells devoid of 5'-3' exonucleases. It also ascribes a role for T4 PNK during normal phage development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriophage T4 / genetics
  • Bacteriophage T4 / growth & development
  • Bacteriophage T4 / metabolism*
  • Base Sequence
  • Endoribonucleases / antagonists & inhibitors
  • Endoribonucleases / metabolism
  • Escherichia coli Proteins / antagonists & inhibitors
  • Escherichia coli Proteins / metabolism
  • Genes, Viral
  • Host-Pathogen Interactions
  • Molecular Sequence Data
  • Polynucleotide 5'-Hydroxyl-Kinase / antagonists & inhibitors
  • Polynucleotide 5'-Hydroxyl-Kinase / metabolism*
  • RNA Stability
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • RNA, Viral / genetics
  • RNA, Viral / metabolism*
  • Viral Proteins / genetics
  • Viral Proteins / metabolism


  • Escherichia coli Proteins
  • RNA, Messenger
  • RNA, Viral
  • Viral Proteins
  • Polynucleotide 5'-Hydroxyl-Kinase
  • Endoribonucleases
  • rng protein, E coli
  • T4 RegB endoribonuclease
  • ribonuclease E