On the role of Cro in lambda prophage induction

Proc Natl Acad Sci U S A. 2005 Mar 22;102(12):4465-9. doi: 10.1073/pnas.0409839102. Epub 2005 Feb 23.

Abstract

The lysogenic state of bacteriophage lambda is exceptionally stable yet the prophage is readily induced in response to DNA damage. This delicate epigenetic switch is believed to be regulated by two proteins; the lysogenic maintenance promoting protein CI and the early lytic protein Cro. First, we confirm, in the native configuration, the previous observation that the DNA loop mediated by oligomerization of CI bound to two distinct operator regions (O(L) and O(R)), increases repression of the early lytic promoters and is important for stable maintenance of lysogeny. Second, we show that the presence of the cro gene might be unimportant for the lysogenic to lytic switch during induction of the lambda prophage. We revisit the idea that Cro's primary role in induction is instead to mediate weak repression of the early lytic promoters.

MeSH terms

  • Bacteriophage lambda / genetics
  • Bacteriophage lambda / physiology*
  • Chromosome Mapping
  • DNA, Viral / chemistry
  • DNA, Viral / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Epigenesis, Genetic
  • Escherichia coli K12 / virology
  • Genes, Reporter
  • Genes, Viral
  • Lysogeny / genetics
  • Lysogeny / physiology
  • Promoter Regions, Genetic
  • Repressor Proteins / genetics
  • Repressor Proteins / physiology*
  • Viral Proteins / genetics
  • Viral Proteins / physiology*
  • Viral Regulatory and Accessory Proteins
  • Virus Activation / genetics
  • Virus Activation / physiology*

Substances

  • DNA, Viral
  • DNA-Binding Proteins
  • Repressor Proteins
  • Viral Proteins
  • Viral Regulatory and Accessory Proteins
  • phage repressor proteins