title: The Zygosaccharomyces bailii transcription factor Haa1 is required for acetic acid and copper stress responses suggesting subfunctionalization of the ancestral bifunctional protein Haa1/Cup2.
abstract: The food spoilage yeast species Zygosaccharomyces bailii exhibits an extraordinary capacity to tolerate weak acids, in particular acetic acid. In Saccharomyces cerevisiae, the transcription factor Haa1 (ScHaa1) is considered the main player in genomic expression reprogramming in response to acetic acid stress, but the role of its homologue in Z. bailii (ZbHaa1) is unknown.
  
  
  
  In this study it is demonstrated that ZbHaa1 is a ScHaa1 functional homologue by rescuing the acetic acid susceptibility phenotype of S. cerevisiae haa1Δ. The disruption of ZbHAA1 in Z. bailii IST302 and the expression of an extra ZbHAA1 copy confirmed ZbHAA1 as a determinant of acetic acid tolerance. ZbHaa1 was found to be required for acetic acid stress-induced transcriptional activation of Z. bailii genes homologous to ScHaa1-target genes. An evolutionary analysis of the Haa1 homologues identified in 28 Saccharomycetaceae species genome sequences, including Z bailii, was carried out using phylogenetic and gene neighbourhood approaches. Consistent with previous studies, this analysis revealed a group containing pre-whole genome duplication species Haa1/Cup2 single orthologues, including ZbHaa1, and two groups containing either Haa1 or Cup2 orthologues from post-whole genome duplication species. S. cerevisiae Cup2 (alias Ace1) is a transcription factor involved in response and tolerance to copper stress. Taken together, these observations led us to hypothesize and demonstrate that ZbHaa1 is also involved in copper-induced transcriptional regulation and copper tolerance.
  
  
  
  The transcription factor ZbHaa1 is required for adaptive response and tolerance to both acetic acid and copper stresses. The subfunctionalization of the single ancestral Haa1/Cup2 orthologue that originated Haa1 and Cup2 paralogues after whole genome duplication is proposed.
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Palma
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Paulo Jorge
authors.initials: PJ
authors.lastname: Dias
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Filipa de Canaveira
authors.initials: FC
authors.lastname: Roque
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Laura
authors.initials: L
authors.lastname: Luzia
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Joana Fernandes
authors.initials: JF
authors.lastname: Guerreiro
authors.affiliation: iBB-Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal. isacorreia@tecnico.ulisboa.pt.
authors.forename: Isabel
authors.initials: I
authors.lastname: Sá-Correia
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000220:Adaptation, Biological; D003001:Cloning, Molecular; D003300:Copper / Q000378:metabolism*; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000378:metabolism*; D015870:Gene Expression; D010802:Phylogeny; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D020068:Zygosaccharomyces / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D003300:Copper; D019342:Acetic Acid
keywords: Acetic acid response and tolerance; Copper response and tolerance; Cup2/Ace1; Haa1; Subfunctionalization; Transcription factors; Yeast