The G-protein alpha-subunit GasC plays a major role in germination in the dimorphic fungus Penicillium marneffei

Abstract

The opportunistic human pathogen Penicillium marneffei exhibits a temperature-dependent dimorphic switch. At 25 degrees, multinucleate, septate hyphae that can undergo differentiation to produce asexual spores (conidia) are produced. At 37 degrees hyphae undergo arthroconidiation to produce uninucleate yeast cells that divide by fission. This work describes the cloning of the P. marneffei gasC gene encoding a G-protein alpha-subunit that shows high homology to members of the class III fungal Galpha-subunits. Characterization of a DeltagasC mutant and strains carrying a dominant-activating gasC(G45R) or a dominant-interfering gasC(G207R) allele show that GasC is a crucial regulator of germina..