Genetic suppression and phenotypic masking of a Myxococcus xanthus frzF- defect

Mol Microbiol. 1995 Feb;15(3):483-94. doi: 10.1111/j.1365-2958.1995.tb02262.x.


An insertion of transposon Tn5-lac, omega 4519, generates a lacZ fusion with a Myxococcus xanthus promoter expressed during both vegetative growth and development. Sequence analysis of the junction of omega 4519 with M. xanthus DNA shows that the insertion is in frzF, a homologue of cheR from Salmonella typhimurium. When frzF- (or frzCD-) cells are starved for nutrients at modest densities, they aggregate to form a radial pattern and produce fewer than 1% of the wild-type complement of spores. At higher densities, frzF::omega 4519 cells form 'frizzy' aggregates and produce 80-90% of the wild-type complement of spores. In contrast, when cells with both a frzF- (or frzCD-) and an sglA1 mutation are allowed to develop at either low or high cell densities, they produce frizzy aggregates containing a near wild-type complement of heat-resistant spores. In addition to suppressing the density dependence of fruiting-body morphogenesis, the sglA1 mutation also suppresses the sporulation defect caused by two different frzF- mutations and a frzCD- mutation. In contrast, a mutation in a different S motility gene, sglG1, does not suppress the frz- mutations. Thus, the suppression of frz- mutations by sgl- mutations is allele-specific, and depends on the sgl allele, but not the frz allele. Because the phenotypes of frz- mutations have been determined in a (suppressing) sglA1 genetic background, the frz genes may play more central roles in development than initially recognized.

Publication types

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

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Base Sequence
  • Cell Movement
  • Chemotaxis
  • DNA Transposable Elements / genetics
  • Genes, Bacterial
  • Methyltransferases / deficiency*
  • Methyltransferases / genetics
  • Methyltransferases / physiology
  • Molecular Sequence Data
  • Morphogenesis
  • Mutagenesis, Insertional
  • Myxococcus xanthus / genetics*
  • Myxococcus xanthus / physiology
  • Operon / genetics
  • Phenotype
  • Spores, Bacterial
  • Suppression, Genetic*


  • Bacterial Proteins
  • DNA Transposable Elements
  • FrzCD protein, Myxococcus xanthus
  • Methyltransferases
  • chemotaxis methyltransferase

Associated data

  • GENBANK/M35200