User:Ilya/Yeast/Phylogeny/Cryptococcus neoformans
- a fungal pathogen that causes meningitis in immunocompromised patients
pathogenic basidiomycete Cryptococcus neoformans has two mating type specific STE12 genes STE12a and STE12α which play different roles in haploid fruiting mating and the regulation of genes [1]
C. neoformans causes meningoencephalitis in humans and animals Strains of the fungus exist in five serotypes (A, B, C, D and AD) and the WM276 strain represents the serotype B group. In general, cryptococcal infections occur at high frequency (10 - 25%) in immunocompromised people such as those individuals infected with the human immunodeficiency virus (HIV). However, serotype B strains also infect immunocompetent (otherwise healthy) people. GSC - C. neoformans summary
It is a heterothallic yeast-like basidiomycete with two mating types, MATalpha and MAT a The S. cerevisiae pheromone response pathway appears to be conserved in C. neoformans. Preliminary molecular studies of mating in C. neoformans have identified a number of genes bearing substantial sequence similarity to S. cerevisiae mating-associated genes. These genes include homologues of GPA1 (Tolkacheva et al., 1994; Alspaugh et al., 1997), STE12 (Wickes et al., 1997), STE4 (Wang et al., 2000) and a pheromone (Moore and Edman, 1993). [2]
Additionally, a phenotype that parallels the S. cerevisiae pseudohyphal response has been identified in C. neoformans. [2]
In spite of the fact that the C. neoformans mating pathway appears to be conserved, which is noteworthy because of the phylogenetic distance from S. cerevisiae, the importance of mating and mating type in this organism lies in virulence. Regardless of serotype or geographical location, the overwhelming majority of C. neoformans infections are caused by the MATalpha mating type [2]
References
- Calcagno AM, Bignell E, Warn P, Jones MD, Denning DW, Mühlschlegel FA, Rogers TR, and Haynes K. Candida glabrata STE12 is required for wild-type levels of virulence and nitrogen starvation induced filamentation. Mol Microbiol. 2003 Nov;50(4):1309-18. DOI:10.1046/j.1365-2958.2003.03755.x |
- Clarke DL, Woodlee GL, McClelland CM, Seymour TS, and Wickes BL. The Cryptococcus neoformans STE11alpha gene is similar to other fungal mitogen-activated protein kinase kinase kinase (MAPKKK) genes but is mating type specific. Mol Microbiol. 2001 Apr;40(1):200-13. DOI:10.1046/j.1365-2958.2001.02375.x |
