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Genetics

Title:		Regulators of pseudohyphal differentiation in Saccharomyces cerevisiae identified through multicopy suppressor analysis in ammonium permease mutant strains
Author(s):		Lorenz MC; Heitman J;
Address:		"Department of Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA"
Journal Title:		Genetics
Year:		1998
Volume:		150
Issue:		4
Page Number:		1443 - 1457
DOI:		10.1093/genetics/150.4.1443
ISSN/ISBN:		0016-6731 (Print) 0016-6731 (Linking)
Abstract:		"Nitrogen-starved diploid cells of the yeast Saccharomyces cerevisiae differentiate into a filamentous, pseudohyphal growth form. Recognition of nitrogen starvation is mediated, at least in part, by the ammonium permease Mep2p and the Galpha subunit Gpa2p. Genetic activation of the pheromone-responsive MAP kinase cascade, which is also required for filamentous growth, only weakly suppresses the filamentation defect of Deltamep2/Deltamep2 and Deltagpa2/Deltagpa2 strain. Surprisingly, deletion of Mep1p, an ammonium permease not previously thought to regulate differentiation, significantly enhances the potency of MAP kinase activation, such that the STE11-4 allele induces filamentation to near wild-type levels in Deltamep1/Deltamep1 Deltamep2/Deltamep2 and Deltamep1/Deltamep1 Deltagpa2/Deltagpa2 strains. To identify additional regulatory components, we isolated high-copy suppressors of the filamentation defect of the Deltamep1/Deltamep1 Deltamep2/Deltamep2 mutant. Multicopy expression of TEC1, PHD1, PHD2 (MSS10/MSN1/FUP4), MSN5, CDC6, MSS11, MGA1, SKN7, DOT6, HMS1, HMS2, or MEP2 each restored filamentation in a Deltamep1/Deltamep1 Deltamep2/Deltamep2 strain. Overexpression of SRK1 (SSD1), URE2, DAL80, MEP1, or MEP3 suppressed only the growth defect of the Deltamep1/Deltamep1 Deltamep2/Deltamep2 mutant strain. Characterization of these genes through deletion analysis and epistasis underscores the complexity of this developmental pathway and suggests that stress conditions other than nitrogen deprivation may also promote filamentous growth"
Keywords:		"Carrier Proteins/genetics/*physiology *Cation Transport Proteins Cell Differentiation Epistasis, Genetic Fungal Proteins/genetics/*physiology *GTP-Binding Protein alpha Subunits GTP-Binding Proteins/genetics/*physiology *Heterotrimeric GTP-Binding Protein;"
Notes:		"MedlineLorenz, M C Heitman, J eng Research Support, Non-U.S. Gov't 1998/12/02 Genetics. 1998 Dec; 150(4):1443-57. doi: 10.1093/genetics/150.4.1443"