The Control of Mating Type Heterokaryon Incompatibility by vib-1, a Locus Involved in Het-C Heterokaryon Incompatibility in Neurospora Crassa

Fungal Genet Biol. 2004 Dec;41(12):1063-76. doi: 10.1016/j.fgb.2004.07.006.


The mating-type (mat) locus of Neurospora crassa has a dual function. It is required for mating during sexual development, but it also mediates heterokaryon incompatibility following hyphal fusion during vegetative growth. Previously, it was determined that mutations in vib-1, which encodes a putative transcriptional regulator, suppress het-c heterokaryon incompatibility. This study showed that mutations in vib-1 suppress mat heterokaryon incompatibility in A/a partial diploids; suppression in (A+a) heterokaryons was variable and affected by unknown genetic factors. tol, a gene required for mat heterokaryon incompatibility, is epistatic to vib-1 in mediating mat heterokaryon incompatibility. vib-1 and tol also display a hierarchical order of strength of heterokaryon incompatibility that affected fertilization patterns. In addition to its role in heterokaryon incompatibility, vib-1 also negatively regulates conidiation. This study shows that FL, a positive regulator of conidiation, may partially activate conidiation by repressing VIB-1 function. VIB-1 may also partially regulate heterokaryon incompatibility mediated by genetic differences at het-e and het-8 because mutations in vib-1 increased the survival rate of self-incompatible het-8 and het-e partial diploid progeny.

Publication types

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

MeSH terms

  • Crosses, Genetic
  • Fungal Proteins / genetics*
  • Fungal Proteins / physiology
  • Gene Expression Regulation, Fungal*
  • Genes, Fungal
  • Genes, Mating Type, Fungal
  • Genes, Suppressor
  • Mutation
  • Neurospora crassa / genetics*
  • Neurospora crassa / growth & development*
  • Transcription Factors / genetics*
  • Transcription Factors / physiology


  • FL protein, Neurospora crassa
  • Fungal Proteins
  • TOL protein, Neurospora crassa
  • Transcription Factors