Open AccessSex-Specific Homeodomain Proteins Sxi1α and Sxi2 a Coordinately Regulate Sexual Development in Cryptococcus neoformans
Author(s) -
Christina M. Hull,
Marie-Josée Boily,
Joseph Heitman
Publication year - 2005
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.4.3.526-535.2005
Subject(s) - biology , homeobox , cryptococcus neoformans , virulence , sexual reproduction , mating , emx2 , genetics , mating type , fungal protein , gene , transcription factor , microbiology and biotechnology , saccharomyces cerevisiae
Homeodomain proteins are central regulators of development in eukaryotes. In fungi, homeodomain proteins have been shown to control cell identity and sexual development. Cryptococcus neoformans is a human fungal pathogen with a defined sexual cycle that produces spores, the suspected infectious particles. Previously, only a single homeodomain regulatory protein involved in sexual development, Sxi1alpha, had been identified. Here we present the discovery of Sxi2a, a predicted but heretofore elusive cell-type-specific homeodomain protein essential for the regulation of sexual development. Our studies reveal that Sxi2a is necessary for proper sexual development and sufficient to drive this development in otherwise haploid alpha cells. We further show that Sxi1alpha and Sxi2a interact with one another and impart similar expression patterns for two key mating genes. The discovery of Sxi2a and its relationship with Sxi1alpha leads to a new model for how the sexual cycle is controlled in C. neoformans, with implications for virulence.