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Physical and functional characterization of the Bacillus subtilis spoIIM gene

K Smith1, M E Bayer, P Youngman

  • 1Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 19104.

Journal of Bacteriology
|June 1, 1993
PubMed

Insights

Bacillus subtilis spoIIM mutations block septum formation and forespore engulfment. The spoIIM gene product is essential for sigma G-dependent gene expression during sporulation.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Cell Biology

Background:

  • The spoIIM locus in Bacillus subtilis is one of six identified genetic loci critical for sporulation.
  • Mutations in these loci can disrupt asymmetric septum synthesis or forespore engulfment during sporangium development.

Purpose of the Study:

  • To investigate the function of the spoIIM gene in Bacillus subtilis sporulation.
  • To determine the role of the spoIIM gene product in gene expression regulation during sporulation.

Main Methods:

  • Ultrastructural analysis of spoIIM mutants.
  • Introduction of spoIIM mutations into strains with lacZ fusions.
  • Complementation studies, gene disruption, and DNA sequencing.

Main Results:

  • Ultrastructure studies revealed a block in engulfment prior to completion in spoIIM mutants.
  • The spoIIM gene product is required for efficient expression of sigma G-dependent genes but not sigma F-dependent genes.
  • The spoIIM locus contains a single sporulation-essential gene encoding a hydrophobic, basic 24,850 Da polypeptide with no significant sequence homology.

Conclusions:

  • The spoIIM gene product plays a crucial role in forespore engulfment.
  • The spoIIM gene product is essential for the activation of sigma G-dependent gene expression during Bacillus subtilis sporulation.

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