Temporal regulation of gene expression of the Escherichia coli bacteriophage phiEco32

J Mol Biol. 2012 Feb 24;416(3):389-99. doi: 10.1016/j.jmb.2012.01.002. Epub 2012 Jan 10.


Escherichia coli phage phiEco32 encodes two proteins that bind to host RNA polymerase (RNAP): gp79, a novel protein, and gp36, a distant homolog of σ(70) family proteins. Here, we investigated the temporal pattern of phiEco32 and host gene expression during infection. Host transcription shutoff and three distinct bacteriophage temporal gene classes (early, middle, and late) were revealed. A combination of bioinformatic and biochemical approaches allowed identification of phage promoters recognized by a host RNAP holoenzyme containing the σ(70) factor. These promoters are located upstream of early phage genes. A combination of macroarray data, primer extension, and in vitro transcription analyses allowed identification of six promoters recognized by an RNAP holoenzyme containing gp36. These promoters are characterized by a single-consensus element tAATGTAtA and are located upstream of the middle and late phage genes. Curiously, gp79, an inhibitor of host and early phage transcription by σ(70) holoenzyme, activated transcription by the gp36 holoenzyme in vitro.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Coliphages / genetics*
  • Computational Biology
  • DNA-Directed RNA Polymerases / metabolism
  • Escherichia coli / virology*
  • Gene Expression Regulation, Viral*
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Sigma Factor / metabolism
  • Transcription, Genetic
  • Transcriptional Activation


  • Sigma Factor
  • RNA polymerase sigma 70
  • DNA-Directed RNA Polymerases