Global transcriptional upregulation in the absence of increased translation in Chlamydia during IFNγ-mediated host cell tryptophan starvation

Scot P. Ouellette, Thomas P. Hatch, Yasser M. AbdelRahman, Lorne A. Rose, Robert J. Belland, Gerald I. Byrne

Research output: Contribution to journalArticle

64 Scopus citations

Abstract

The developmentally regulated intracellular pathogen Chlamydia pneumoniae is a natural tryptophan auxotroph. These organisms survive tryptophan starvation induced by host cell activation with IFNγ by blocking maturation to the infectious form. In most bacteria, the stringent response is induced during amino acid starvation to promote survival. However, the response of obligate intracellular pathogens, which are predicted to lack stringent responses to amino acid starvation, is poorly characterized. Chlamydial transcription and translation were analysed during IFNγ-mediated tryptophan starvation using genomic normalization methods, and the data revealed the novel findings that: (i) global chlamydial transcription was upregulated; and (ii) protein synthesis was dramatically reduced. These results indicate a dysregulation of developmental gene expression and an uncoupling of transcription from translation. These observations represent an alternative survival strategy for host-adapted obligate intracellular bacterial pathogens that have lost the genes for stringent control during reductive evolution.

Original languageEnglish (US)
Pages (from-to)1387-1401
Number of pages15
JournalMolecular Microbiology
Volume62
Issue number5
DOIs
StatePublished - Dec 1 2006

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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