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Y ap7 is a transcriptional repressor of nitric oxide oxidase in yeasts, which arose from neofunctionalization after whole genome duplication
Author(s) -
Merhej Jawad,
Delaveau Thierry,
Guitard Juliette,
Palancade Benoit,
Hennequin Christophe,
Garcia Mathilde,
Lelandais Gaëlle,
Devaux Frédéric
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12983
Subject(s) - biology , neofunctionalization , derepression , genetics , repressor , saccharomyces cerevisiae , transcription factor , gene duplication , repressor lexa , gene , candida glabrata , transcriptional regulation , transcription (linguistics) , psychological repression , gene expression , candida albicans , linguistics , philosophy
Summary Flavohemoglobins are the main detoxifiers of nitric oxide ( NO ) in bacteria and fungi and are induced in response to nitrosative stress. In fungi, the flavohemoglobin encoding gene YHB 1 is positively regulated by transcription factors which are activated upon NO exposure. In this study, we show that in the model yeast S accharomyces cerevisiae and in the human pathogen C andida glabrata , the transcription factor Y ap7 constitutively represses YHB 1 by binding its promoter. Consequently, YAP 7 deletion conferred high NO resistance to the cells. Co‐immunoprecipitation experiments and mutant analyses indicated that Y ap7 represses YHB 1 by recruiting the transcriptional repressor T up1. In S . cerevisiae , YHB 1 repression also involves interaction of Y ap7 with the H ap2/3/5 complex through a conserved Hap4‐like‐b ZIP domain, but this interaction has been lost in C . glabrata . The evolutionary origin of this regulation was investigated by functional analyses of Y ap7 and of its paralogue Y ap5 in different yeast species. These analyses indicated that the negative regulation of YHB 1 by Y ap7 arose by neofunctionalization after the whole genome duplication which led to the C . glabrata and S . cerevisiae extant species. This work describes a new aspect of the regulation of fungal nitric oxidase and provides detailed insights into its functioning and evolution.