title: The zinc cluster proteins Upc2 and Ecm22 promote filamentation in Saccharomyces cerevisiae by sterol biosynthesis-dependent and -independent pathways.
abstract: The transition between a unicellular yeast form to multicellular filaments is crucial for budding yeast foraging and the pathogenesis of many fungal pathogens such as Candida albicans. Here, we examine the role of the related transcription factors Ecm22 and Upc2 in Saccharomyces cerevisiae filamentation. Overexpression of either ECM22 or UPC2 leads to increased filamentation, whereas cells lacking both ECM22 and UPC2 do not exhibit filamentous growth. Ecm22 and Upc2 positively control the expression of FHN1, NPR1, PRR2 and sterol biosynthesis genes. These genes all play a positive role in filamentous growth, and their expression is upregulated during filamentation in an Ecm22/Upc2-dependent manner. Furthermore, ergosterol content increases during filamentous growth. UPC2 expression also increases during filamentation and is inhibited by the transcription factors Sut1 and Sut2. The expression of SUT1 and SUT2 in turn is under negative control of the transcription factor Ste12. We suggest that during filamentation Ste12 becomes activated and reduces SUT1/SUT2 expression levels. This would result in increased UPC2 levels and as a consequence to transcriptional activation of FHN1, NPR1, PRR2 and sterol biosynthesis genes. Higher ergosterol levels in combination with the proteins Fhn1, Npr1 and Prr2 would then mediate the transition to filamentous growth.
authors.affiliation: Division of Biosciences, Brunel University London, Uxbridge, UK.
authors.forename: Kelly
authors.initials: K
authors.lastname: Woods
authors.affiliation: Division of Biosciences, Brunel University London, Uxbridge, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Höfken
mesh_terms: D015966:Gene Expression Regulation, Fungal; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013261:Sterols / Q000096:biosynthesis*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: C465208:ECM22 protein, S cerevisiae; C489241:STE12 protein, S cerevisiae; C547000:SUT1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D015534:Trans-Activators; D014157:Transcription Factors; C113958:UPC2 protein, S cerevisiae; D015032:Zinc