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PLoS One

Title:		Cryptococcus neoformans mediator protein Ssn8 negatively regulates diverse physiological processes and is required for virulence
Author(s):		Wang LI; Lin YS; Liu KH; Jong AY; Shen WC;
Address:		"Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan"
Journal Title:		PLoS One
Year:		2011
Volume:		20110429
Issue:		4
Page Number:		e19162 -
DOI:		10.1371/journal.pone.0019162
ISSN/ISBN:		1932-6203 (Electronic) 1932-6203 (Linking)
Abstract:		"Cryptococcus neoformans is a ubiquitously distributed human pathogen. It is also a model system for studying fungal virulence, physiology and differentiation. Light is known to inhibit sexual development via the evolutionarily conserved white collar proteins in C. neoformans. To dissect molecular mechanisms regulating this process, we have identified the SSN8 gene whose mutation suppresses the light-dependent CWC1 overexpression phenotype. Characterization of sex-related phenotypes revealed that Ssn8 functions as a negative regulator in both heterothallic a-alpha mating and same-sex mating processes. In addition, Ssn8 is involved in the suppression of other physiological processes including invasive growth, and production of capsule and melanin. Interestingly, Ssn8 is also required for the maintenance of cell wall integrity and virulence. Our gene expression studies confirmed that deletion of SSN8 results in de-repression of genes involved in sexual development and melanization. Epistatic and yeast two hybrid studies suggest that C. neoformans Ssn8 plays critical roles downstream of the Cpk1 MAPK cascade and Ste12 and possibly resides at one of the major branches downstream of the Cwc complex in the light-mediated sexual development pathway. Taken together, our studies demonstrate that the conserved Mediator protein Ssn8 functions as a global regulator which negatively regulates diverse physiological and developmental processes and is required for virulence in C. neoformans"
Keywords:		"Animals Conserved Sequence Cryptococcus neoformans/*metabolism/*pathogenicity Cyclin C/genetics/*physiology Fungal Proteins/genetics/*physiology Galactose/chemistry Gene Deletion *Gene Expression Regulation, Fungal MAP Kinase Signaling System Mating Facto;"
Notes:		"MedlineWang, Lin-Ing Lin, Yu-Sheng Liu, Kung-Hung Jong, Ambrose Y Shen, Wei-Chiang eng Research Support, Non-U.S. Gov't 2011/05/12 PLoS One. 2011 Apr 29; 6(4):e19162. doi: 10.1371/journal.pone.0019162"