A novel lysis system in PM2, a lipid-containing marine double-stranded DNA bacteriophage

Mol Microbiol. 2007 Jun;64(6):1635-48. doi: 10.1111/j.1365-2958.2007.05769.x.

Abstract

In this study we investigated the lysis system of the lipid-containing double-stranded DNA bacteriophage PM2 infecting Gram-negative marine Pseudoalteromonas species. We analysed wt and lysis-deficient phage-induced changes in the host physiology and ascribed functions to two PM2 gene products (gp) involved in lysis. We show that bacteriophage PM2 uses a novel system to disrupt the infected cell. The novelty is based on the following findings: (i) gp k is needed for the permeabilization of the cytoplasmic membrane and appears to play the role of a typical holin. However, its unique primary structure [53 aa, 1 transmembrane domain (TMD)] places it into a new class of holins. (ii) We have proposed that, unlike other bacteriophages studied, PM2 relies on lytic factors of the cellular origin for digestion of the peptidoglycan. (iii) gp l (51 aa, no TMDs) is needed for disruption of the outer membrane, which is highly rigidified by the divalent cations abundant in the marine environment. The gp l has no precedent in other phage lytic systems studied so far. However, the presence of open reading frame l-like genes in genomes of other bacterial viruses suggests that the same system might be used by other phages and is not unique to PM2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacteriolysis*
  • Corticoviridae / chemistry
  • Corticoviridae / genetics
  • Corticoviridae / physiology*
  • DNA / genetics
  • Lipids / analysis*
  • Lysogeny
  • Molecular Sequence Data
  • Pseudoalteromonas / physiology*
  • Pseudoalteromonas / virology*
  • Seawater / microbiology
  • Seawater / virology*
  • Viral Proteins / chemistry
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*

Substances

  • Lipids
  • Viral Proteins
  • DNA