A pheromone receptor gene, pre-1, is essential for mating type-specific directional growth and fusion of trichogynes and female fertility in Neurospora crassa.
Neurospora crassa is a heterothallic filamentous fungus with two mating types, mat a and mat A. Its mating involves differentiation of female reproductive structures (protoperithecia) and chemotropic growth of female-specific hyphae (trichogynes) towards a cell of the opposite mating type in a pheromone-mediated process. In this study, we characterize the pre-1 gene, encoding a predicted G-protein-coupled receptor with sequence similarity to fungal pheromone receptors. pre-1 is most highly expressed in mat A strains under mating conditions, but low levels can also be detected in mat a strains. Analysis of pre-1 deletion mutants showed that loss of pre-1 does not greatly affect vegetative growth, heterokaryon formation or male fertility in either mating type. Protoperithecia from Deltapre-1 mat A mutants do not undergo fertilization; this defect largely stems from an inability of their trichogynes to recognize and fuse with mat a cells. Previous work has demonstrated that the Galpha subunit, GNA-1, and the Gbeta protein, GNB-1, are essential for female fertility in N. crassa. Trichogynes of Deltagna-1 and Deltagnb-1 mutants displayed severe defects in growth towards and fusion with male cells, similar to that of Deltapre-1 mat A strains. However, the female sterility defect of the Deltapre-1 mat A mutant could not be complemented by constitutive activation of gna-1, suggesting additional layers of regulation. We propose that PRE-1 is a pheromone receptor coupled to GNA-1 that is essential for the mating of mat A strains as females, consistent with a role in launching the pheromone response pathway in N. crassa.
Kim
Hyojeong
H
Department of Plant Pathology, University of California, 2338 Webber Hall, 900 University Avenue, Riverside, CA 92521, USA.
Borkovich
Katherine A
KA
D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D020043:Genes, Essential; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D005816:Genetic Complementation Test; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D043563:Receptors, Pheromone / Q000235:genetics* / Q000502:physiology*
D005656:Fungal Proteins; C410129:GNA-1 protein, Neurospora crassa; D043563:Receptors, Pheromone; D019206:GTP-Binding Protein alpha Subunits, Gi-Go