G-protein signaling mediates asexual development at 25°C but has no effect on yeast-like growth at 37°C in the dimorphic fungus Penicillium marneffei

Abstract

The ascomycete Penicillium marneffei is an opportunistic human pathogen exhibiting a temperature-dependent dimorphic switch. At 25°C, P. marneffei grows as filamentous multinucleate hyphae and undergoes asexual development, producing uninucleate spores. At 37°C, it forms uninucleate yeast cells which divide by fission. We have cloned a gene encoding a Gα subunit of a heterotrimeric G protein from P. marneffei named gasA with high similarity to fadA in Aspergillus nidulans. Through the characterization of a ΔgasA strain and mutants carrying a dominant activating or a dominant interfering gasA allele, we show that GasA is a key regulator of asexual development but seems to play no role in the ..