Pheromones stimulate mating and differentiation via paracrine and autocrine signaling in Cryptococcus neoformans.

Published

Journal Article

Cryptococcus neoformans is a pathogenic fungus with a defined sexual cycle involving haploid MATalpha and MATa cells. Interestingly, MATalpha strains are more common, are more virulent than congenic MATa strains, and undergo haploid fruiting in response to nitrogen limitation or MATa cells. Three genes encoding the MFalpha pheromone were identified in the MATalpha mating-type locus and shown to be transcriptionally induced by limiting nutrients and coculture with MATa cells. The MFalpha1, MFalpha2, and MFalpha3 genes were mutated, individually and in combination. MATalpha strains lacking MFalpha pheromone failed to induce morphological changes in MATa cells. Pheromoneless MATalpha mutants were fusion and mating impaired but not sterile and mated at approximately 1% the wild-type level. The pheromoneless MATalpha mutants were also partially defective in haploid fruiting, and overexpression of MFalpha pheromone enhanced haploid fruiting. Overexpression of MFa pheromone also enhanced haploid fruiting of MATalpha cells and stimulated conjugation tube formation in MATa cells. A conserved G-protein activated mitogen-activated protein kinase signaling pathway was found to be required for both induction and response to mating pheromones. The MFalpha pheromone was not essential for virulence of C. neoformans but does contribute to the overall virulence composite. These studies define paracrine and autocrine pheromone response pathways that signal mating and differentiation of this pathogenic fungus.

Full Text

Duke Authors

Cited Authors

  • Shen, W-C; Davidson, RC; Cox, GM; Heitman, J

Published Date

  • June 2002

Published In

Volume / Issue

  • 1 / 3

Start / End Page

  • 366 - 377

PubMed ID

  • 12455985

Pubmed Central ID

  • 12455985

International Standard Serial Number (ISSN)

  • 1535-9778

Digital Object Identifier (DOI)

  • 10.1128/ec.1.3.366-377.2002

Language

  • eng

Conference Location

  • United States