title: The heterotrimeric G-protein subunits GNG-1 and GNB-1 form a Gbetagamma dimer required for normal female fertility, asexual development, and galpha protein levels in Neurospora crassa.
abstract: We have identified a gene encoding a heterotrimeric G protein gamma subunit, gng-1, from the filamentous fungus Neurospora crassa. gng-1 possesses a gene structure similar to that of mammalian Ggamma genes, consisting of three exons and two introns, with introns present in both the open reading frame and 5'-untranslated region. The GNG-1 amino acid sequence displays high identity to predicted Ggamma subunits from other filamentous fungi, including Giberella zeae, Cryphonectria parasitica, Trichoderma harzianum, and Magnaporthe grisea. Deletion of gng-1 leads to developmental defects similar to those previously characterized for Deltagnb-1 (Gbeta) mutants. Deltagng-1, Deltagnb-1, and Deltagng-1 Deltagnb-1 strains conidiate inappropriately in submerged cultures and are female sterile, producing aberrant female reproductive structures. Similar to previous results obtained with Deltagnb-1 mutants, loss of gng-1 negatively influences levels of Galpha proteins (GNA-1, GNA-2, and GNA-3) in plasma membrane fractions isolated from various tissues of N. crassa and leads to a significant reduction in the amount of intracellular cyclic AMP. In addition, we show that GNB-1 is essential for maintenance of normal steady-state levels of GNG-1, suggesting a functional interaction between GNB-1 and GNG-1. Direct evidence for a physical association between GNB-1 and GNG-1 in vivo was provided by coimmunoprecipitation.
authors.affiliation: Department of Plant Pathology, University of California-Riverside, Riverside, CA 92521, USA.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Krystofova
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Borkovich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D019281:Dimerization; D005260:Female; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D018390:Gene Targeting; D008969:Molecular Sequence Data; D009492:Neurospora crassa / Q000166:cytology / Q000502:physiology*; D010641:Phenotype; D020836:Protein Structure, Quaternary; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D005656:Fungal Proteins; D044385:GTP-Binding Protein alpha Subunits; D044388:GTP-Binding Protein gamma Subunits; D012333:RNA, Messenger; D000242:Cyclic AMP