title: Multiple roles of a heterotrimeric G-protein gamma-subunit in governing growth and development of Aspergillus nidulans.
abstract: Vegetative growth signaling in the filamentous fungus Aspergillus nidulans is primarily mediated by the heterotrimeric G-protein composed of FadA (G alpha), SfaD (G beta), and a presumed G gamma. Analysis of the A. nidulans genome identified a single gene named gpgA encoding a putative G gamma-subunit. The predicted GpgA protein consists of 90 amino acids showing 72% similarity with yeast Ste18p. Deletion (delta) of gpgA resulted in restricted vegetative growth and lowered asexual sporulation. Moreover, similar to the delta sfaD mutant, the delta gpgA mutant was unable to produce sexual fruiting bodies (cleistothecia) in self-fertilization and was severely impaired with cleistothecial development in outcross, indicating that both SfaD and GpgA are required for fruiting body formation. Developmental and morphological defects caused by deletion of flbA encoding an RGS protein negatively controlling FadA-mediated vegetative growth signaling were suppressed by delta gpgA, indicating that GpgA functions in FadA-SfaD-mediated vegetative growth signaling. However, deletion of gpgA could not bypass the need for the early developmental activator FluG in asexual sporulation, suggesting that GpgA functions in a separate signaling pathway. We propose that GpgA is the only A. nidulans G gamma-subunit and is required for normal vegetative growth as well as proper asexual and sexual developmental progression.
authors.affiliation: Department of Food Microbiology and Toxicology, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: Jeong-Ah
authors.initials: JA
authors.lastname: Seo
authors.forename: Kap-Hoon
authors.initials: KH
authors.lastname: Han
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D044388:GTP-Binding Protein gamma Subunits / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D015966:Gene Expression Regulation, Fungal; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development
chemical_list: C089966:FLUG protein, Emericella nidulans; D005656:Fungal Proteins; D044388:GTP-Binding Protein gamma Subunits