A conserved G protein (Drg1p) plays a role in regulation of invasive filamentation in Candida albicans

During infection, the opportunistic fungal pathogen Candida albicans grows invasively into the tissues of its host, forming filaments that penetrate the host tissue. To search for genes that are important for invasive filamentation, a screen for mutants that were defective in invasion of agar medium was conducted. A mutant carrying an insertion mutation in the locus of a gene, termed here DRG1, was identified. DRG1 encodes a highly conserved cytoplasmic G protein, with orthologues in the genomes of organisms from humans to yeast and archaea. C. albicans strains lacking Drg1p were defective in producing filaments that penetrated agar media, but produced filaments normally under other conditions, such as during liquid growth. When inoculated intravenously into mice, the drg1 null mutant caused delayed lethality accompanied by delayed invasive growth in the kidneys of the host, in comparison with those of the wild-type strain. These results implicate Drg1p in the control of invasive filamentation in the laboratory, and in the progression of invasive disease in the host. DOI 10.1099/mic.0.29246-0