Roles for receptors, pheromones, G proteins, and mating type genes during sexual reproduction in Neurospora crassa.
Here we characterize the relationship between the PRE-2 pheromone receptor and its ligand, CCG-4, and the general requirements for receptors, pheromones, G proteins, and mating type genes during fusion of opposite mating-type cells and sexual sporulation in the multicellular fungus Neurospora crassa. PRE-2 is highly expressed in mat a cells and is localized in male and female reproductive structures. Δpre-2 mat a females do not respond chemotropically to mat A males (conidia) or form mature fruiting bodies (perithecia) or meiotic progeny (ascospores). Strains with swapped identity due to heterologous expression of pre-2 or ccg-4 behave normally in crosses with opposite mating-type strains. Coexpression of pre-2 and ccg-4 in the mat A background leads to self-attraction and development of barren perithecia without ascospores. Further perithecial development is achieved by inactivation of Sad-1, a gene required for meiotic gene silencing. Findings from studies involving forced heterokaryons of opposite mating-type strains show that presence of one receptor and its compatible pheromone is necessary and sufficient for perithecial development and ascospore production. Taken together, the results demonstrate that although receptors and pheromones control sexual identity, the mating-type genes (mat A and mat a) must be in two different nuclei to allow meiosis and sexual sporulation to occur.
Department of Plant Pathology and Microbiology, Program in Biochemistry and Molecular Biology, University of California, Riverside, California 92521, USA.
Hyojeong
H
Kim
Sara J
SJ
Wright
Gyungsoon
G
Park
Shouqiang
S
Ouyang
Svetlana
S
Krystofova
Katherine A
KA
Borkovich
D001233:Aspergillus nidulans / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002633:Chemotaxis; D003433:Crosses, Genetic; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D005298:Fertility; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D049770:Genes, Mating Type, Fungal; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D025301:Hyphae / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008540:Meiosis; D009492:Neurospora crassa / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010675:Pheromones / Q000235:genetics / Q000378:metabolism*; D043563:Receptors, Pheromone / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012098:Reproduction; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism
D004271:DNA, Fungal; D005656:Fungal Proteins; D010675:Pheromones; D043563:Receptors, Pheromone; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D019204:GTP-Binding Proteins