A gene required for nuclear migration in Neurospora crassa codes for a protein with cysteine-rich, LIM/RING-like domains

Mol Microbiol. 1997 Apr;24(2):331-40. doi: 10.1046/j.1365-2958.1997.3461704.x.

Abstract

The ro mutants of Neurospora crassa are defective in nuclear migration and hyphal morphogenesis. Several of the ro loci have recently been shown to encode components of the dynein/dynactin motor complex. Here we report on the cloning and characterization of the ro-2 gene which codes for a novel 80 kDa protein that has two Cys-rich motifs which resemble zinc-binding LIM or RING domains thought to mediate protein-protein interactions. RO2 also contains several potential binding sites for Src homology 3 (SH3) domains. The ro-2B20 allele has a frameshift mutation within one of the Cys-rich domains which eliminates the C-terminal half of the open reading frame (ORF). Disruption of the ro-2 locus by repeat-induced point (RIP) mutation gave rise to progeny which have a nuclear migration defect, but which are also blocked in conidiation. The ability to assemble cytoplasmic microtubules and actin is maintained in ro-2 mutants, although subapical actin patches are more prominent. Based on these observations, the RO2 gene product is proposed to play a role in mediating interactions between components of the dynein/dynactin motor complex or in linking this complex to the nucleus or cytoskeleton.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Alleles
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Cell Nucleus / physiology
  • Cloning, Molecular*
  • Cysteine / genetics
  • Dyneins / genetics*
  • Frameshift Mutation
  • Gene Expression Regulation, Fungal
  • Microtubules / metabolism
  • Neurospora crassa / genetics*
  • Open Reading Frames
  • Point Mutation
  • src Homology Domains / genetics

Substances

  • Actins
  • Dyneins
  • Cysteine