Sok2 regulates yeast pseudohyphal differentiation via a transcription factor cascade that regulates cell-cell adhesion.
In response to nitrogen limitation, Saccharomyces cerevisiae undergoes a dimorphic transition to filamentous pseudohyphal growth. In previous studies, the transcription factor Sok2 was found to negatively regulate pseudohyphal differentiation. By genome array and Northern analysis, we found that genes encoding the transcription factors Phd1, Ash1, and Swi5 were all induced in sok2/sok2 hyperfilamentous mutants. In accord with previous studies of others, Swi5 was required for ASH1 expression. Phd1 and Ash1 regulated expression of the cell surface protein Flo11, which is required for filamentous growth, and were largely required for filamentation of sok2/sok2 mutant strains. These findings reveal that a complex transcription factor cascade regulates filamentation. These findings also reveal a novel dual role for the transcription factor Swi5 in regulating filamentous growth. Finally, these studies illustrate how mother-daughter cell adhesion can be accomplished by two distinct mechanisms: one involving Flo11 and the other involving regulation of the endochitinase Cts1 and the endoglucanase Egt2 by Swi5.
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Departments of Genetics, Pharmacology and Cancer Biology, Microbiology, and Medicine, Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
Heitman
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J
D002448:Cell Adhesion / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002688:Chitinases / Q000235:genetics / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D013172:Spores, Fungal / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C098733:ASH1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C099941:EGT2 protein, S cerevisiae; C110690:FLO11 protein, S cerevisiae; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C085984:PHD1 protein, S cerevisiae; D012097:Repressor Proteins; C097076:SOK2 protein, S cerevisiae; C080218:SWI5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D017868:Cyclic AMP-Dependent Protein Kinases; C121990:CTS1 protein, S cerevisiae; D002688:Chitinases; D009584:Nitrogen