Cytoplasmic dynein and actin-related protein Arp1 are required for normal nuclear distribution in filamentous fungi.
Cytoplasmic dynein is a multisubunit, microtubule-dependent mechanochemical enzyme that has been proposed to function in a variety of intracellular movements, including minus-end-directed transport of organelles. Dynein-mediated vesicle transport is stimulated in vitro by addition of the Glued/dynactin complex raising the possibility that these two complexes interact in vivo. We report here that a class of phenotypically identical mutants of the filamentous fungus Neurospora crassa are defective in genes encoding subunits of either cytoplasmic dynein or the Glued/dynactin complex. These mutants, defined as ropy, have curled hyphae with abnormal nuclear distribution. ro-1 encodes the heavy chain of cytoplasmic dynein, while ro-4 encodes an actin-related protein that is a probable homologue of the actin-related protein Arpl (formerly referred to as actin-RPV or centractin), the major component of the glued/dynactin complex. The phenotypes of ro-1 and ro-4 mutants suggest that cytoplasmic dynein, as well as the Glued/dynactin complex, are required to maintain uniform nuclear distribution in fungal hyphae. We propose that cytoplasmic dynein maintains nuclear distribution through sliding of antiparallel microtubules emanating from neighboring spindle pole bodies.
Plamann
M
M
Department of Biology, Texas A&M University, College Station 77843-3258.
Minke
P F
PF
Tinsley
J H
JH
Bruno
K S
KS
D000199:Actins / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000502:physiology*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000737:chemistry; D004398:Dyneins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation / Q000502:physiology; D009492:Neurospora crassa / Q000235:genetics* / Q000648:ultrastructure; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic
D000199:Actins; D005656:Fungal Proteins; C089654:RO-4 protein, Neurospora crassa; C076834:centractin; D017346:Protein Serine-Threonine Kinases; D004398:Dyneins; C089653:RO-1 protein, Neurospora crassa