Heterotrimeric G proteins, consisting of alpha, beta and gamma subunits, mediate a variety of signaling pathways in eukaryotes. We have previously identified two genes, gna-1 and gna-2, that encode G protein alpha subunits in the filamentous fungus @entity1980 . Mutation of gna-1 results in @entity9814 and sensitivity to hyperosmotic media. In this study, we investigate the expression and functions of gna-2. Results from Western analysis and measurements of gna-2 promoter-lacZ fusion activity indicate that gna-2 is expressed during the vegetative and sexual cycle of @entity1980 in both A and a mating types. Activating mutations predicted to abolish the GTPase activity of GNA-2 cause @entity154 in @entity8233 . Extensive phenotypic analysis of delta gna-2 strains did not reveal abnormalities during vegetative or sexual development. In contrast, deletion of gna-2 in a delta gna-1 strain accentuates the delta gna-1 phenotypes. delta gna- @entity33599 gna-2 strains have a slower rate of hyphal apical extension than delta gna-1 strains on hyperosmotic media. Moreover, delta gna- @entity33599 gna-2 mutants have more pronounced defects in female fertility than delta gna-1 strains. We propose that gna-1 and gna-2 have overlapping functions and may constitute a gene family. This is the first report of G protein alpha subunits with overlapping functions in eukaryotic microbes.

Overlapping functions for two G protein alpha subunits in XXXX .

@entity154 :: ('MESH:D000013', 'Disease') :: ['subtle defects'] @entity1980 :: ('5141', 'Species') :: ['Neurospora crassa', 'N. crassa'] @entity9814 :: ('MESH:D007247', 'Disease') :: ['female infertility'] @entity33599 :: ('1 delta', 'DNAMutation') :: ['1 delta'] @entity8233 :: ('MESH:D058426', 'Disease') :: ['aerial hyphae formation and conidial germination']
@entity1980 :: (5141,Species) :: ['Neurospora crassa']
