Genetics, Vol. 178, 145-156, January 2008, Copyright © 2008
doi:10.1534/genetics.107.081315
Identification of Novel Activation Mechanisms for FLO11 Regulation in Saccharomyces cerevisiae
Ramón R. Barrales,
Juan Jimenez and
José I. Ibeas1
Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC, 41013 Sevilla, Spain
1 Corresponding author: Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC, Carretera de Utrera, Km1, 41013 Sevilla, Spain.
E-mail: joibecor{at}upo.es
Adhesins play a central role in the cellular response of eukaryotic microorganisms to their host environment. In pathogens such as Candida spp. and other fungi, adhesins are responsible for adherence to mammalian tissues, and in Saccharomyces spp. yeasts also confer adherence to solid surfaces and to other yeast cells. The analysis of FLO11, the main adhesin identified in Saccharomyces cerevisiae, has revealed complex mechanisms, involving both genetic and epigenetic regulation, governing the expression of this critical gene. We designed a genomewide screen to identify new regulators of this pivotal adhesin in budding yeasts. We took advantage of a specific FLO11 allele that confers very high levels of FLO11 expression to wild "flor" strains of S. cerevisiae. We screened for mutants that abrogated the increased FLO11 expression of this allele using the loss of the characteristic fluffy-colony phenotype and a reporter plasmid containing GFP controlled by the same FLO11 promoter. Using this approach, we isolated several genes whose function was essential to maintain the expression of FLO11. In addition to previously characterized activators, we identified a number of novel FLO11 activators, which reveal the pH response pathway and chromatin-remodeling complexes as central elements involved in FLO11 activation.
Copyright © 2008 by the Genetics Society of America.