The coat morphogenetic protein SpoVID is necessary for spore encasement in Bacillus subtilis

Mol Microbiol. 2009 Nov;74(3):634-49. doi: 10.1111/j.1365-2958.2009.06886.x. Epub 2009 Sep 22.


Endospores formed by Bacillus subtilis are encased in a tough protein shell known as the coat, which consists of at least 70 different proteins. We investigated the process of spore coat morphogenesis using a library of 40 coat proteins fused to green fluorescent protein and demonstrate that two successive steps can be distinguished in coat assembly. The first step, initial localization of proteins to the spore surface, is dependent on the coat morphogenetic proteins SpoIVA and SpoVM. The second step, spore encasement, requires a third protein, SpoVID. We show that in spoVID mutant cells, most coat proteins assembled into a cap at one side of the developing spore but failed to migrate around and encase it. We also found that SpoIVA directly interacts with SpoVID. A domain analysis revealed that the N-terminus of SpoVID is required for encasement and is a structural homologue of a virion protein, whereas the C-terminus is necessary for the interaction with SpoIVA. Thus, SpoVM, SpoIVA and SpoVID are recruited to the spore surface in a concerted manner and form a tripartite machine that drives coat formation and spore encasement.

Publication types

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

MeSH terms

  • Amino Acid Substitution
  • Bacillus subtilis / cytology
  • Bacillus subtilis / genetics
  • Bacillus subtilis / physiology*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology*
  • Conserved Sequence / genetics
  • DNA, Bacterial / analysis
  • DNA, Bacterial / genetics
  • DNA, Bacterial / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Green Fluorescent Proteins / analysis
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Membrane Proteins / analysis
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Microscopy, Fluorescence
  • Morphogenesis / genetics
  • Mutation
  • Peptide Library
  • Promoter Regions, Genetic
  • Recombinant Fusion Proteins / analysis
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Sequence Homology, Amino Acid
  • Spores, Bacterial / chemistry
  • Spores, Bacterial / genetics
  • Spores, Bacterial / metabolism
  • Two-Hybrid System Techniques


  • Bacterial Proteins
  • DNA, Bacterial
  • Membrane Proteins
  • Peptide Library
  • Recombinant Fusion Proteins
  • spoVID protein, Bacillus subtilis
  • Green Fluorescent Proteins