The G alpha i homologue gna-1 controls multiple differentiation pathways in Neurospora crassa.
Heterotrimeric G proteins are components of principal signaling pathways in eukaryotes. In higher organisms, alpha subunits of G proteins have been divided into four families, Gi, Gs, Gq, and G12. We previously identified a G alpha i homologue gna-1 in the filamentous fungus Neurospora crassa. Now we report that deletion of gna-1 leads to multiple phenotypes during the vegetative and sexual cycles in N. crassa. On solid medium, delta gna-1 strains have a slower rate of hyphal apical extension than wild type, a rate that is more pronounced under hyperosmotic conditions or in the presence of a cellophane overlay. delta gna-1 mutants accumulate less mass than wild-type strains, and their mass accumulation is not affected in the same way by exposure to light. delta gna-1 strains are defective in macroconidiation, possessing aerial hyphae that are shorter, contain abnormal swellings, and differentiate adherent macroconidia. During the sexual cycle, delta gna-1 strains are fertile as males. However, the mutants are female-sterile, producing small, aberrant female reproductive structures. After fertilization, delta gna-1 female structures do not enlarge and develop normally, and no sexual spores are produced. Thus, mutation of gna-1 results in sex-specific loss of fertility.
Ivey
F D
FD
Department of Microbiology and Molecular Genetics, University of Texas-Houston Medical School 77030, USA.
Hodge
P N
PN
Turner
G E
GE
Borkovich
K A
KA
D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division; D017931:DNA Primers / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics*; D017353:Gene Deletion; D018390:Gene Targeting; D005800:Genes, Fungal; D009492:Neurospora crassa / Q000166:cytology* / Q000235:genetics* / Q000254:growth & development; D009997:Osmotic Pressure; D010641:Phenotype
D017931:DNA Primers; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019204:GTP-Binding Proteins