The resuscitation-promoting factors of Mycobacterium tuberculosis are required for virulence and resuscitation from dormancy but are collectively dispensable for growth in situ

Authors Organisations
  • Bavesh D. Kana(Author)
    University of the Witwatersrand
  • Bhavna G. Gordhan(Author)
    University of the Witwatersrand
  • Katrina J. Downing(Author)
    University of the Witwatersrand
  • Nackmoon Sung(Author)
    Public Health Research Institute, New Jersey
  • Galina Vostroktunova(Author)
    Bakh Institute of Biochemistry
  • Edith E. Machowski(Author)
    University of the Witwatersrand
  • Liana Tsenova(Author)
    Public Health Research Institute, New Jersey
  • Mike Young(Author)
  • Arseny S. Kaprelyants(Author)
    Bakh Institute of Biochemistry
  • Gilla Kaplan(Author)
    Public Health Research Institute, New Jersey
  • Valerie Mizrahi(Author)
    Public Health Research Institute, New Jersey
Type Article
Original languageEnglish
Pages (from-to)672-684
Number of pages13
JournalMolecular Microbiology
Volume67
Issue number3
Early online date21 Dec 2007
DOI
Publication statusPublished - 01 Feb 2008
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Abstract

Mycobacterium tuberculosis contains five resuscitation-promoting factor (Rpf)-like proteins, RpfA-E, that are implicated in resuscitation of this organism from dormancy via a mechanism involving hydrolysis of the peptidoglycan by Rpfs and partnering proteins. In this study, the rpfA-E genes were shown to be collectively dispensable for growth of M. tuberculosis in broth culture. The defect in resuscitation of multiple mutants from a 'non-culturable' state induced by starvation under anoxia was reversed by genetic complementation or addition of culture filtrate from wild-type organisms confirming that the phenotype was associated with rpf-like gene loss and that the 'non-culturable' cells of the mutant strains were viable. Other phenotypes uncovered by sequential deletion mutagenesis revealed a functional differentiation within this protein family. The quintuple mutant and its parent that retained only rpfD displayed delayed colony formation and hypersensitivity to detergent, effects not observed for mutants retaining only rpfE or rpfB. Furthermore, mutants retaining rpfD or rpfE were highly attenuated for growth in mice with the latter persisting better than the former in late-stage infection. In conjunction, these results are indicative of a hierarchy in terms of function and/or potency with the Rpf family, with RpfB and RpfE ranking above RpfD.