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[摘要]：We have characterized the KIROX1 gene from Kluyveromyces lactis and verified that it does not regulate the hypoxic response in this yeast, oppositely to the Saccharomyces cerevisioe homologue ScROX1. The KIROX1 promoter is not regulated by KIHap1p or KIRox1p in response to changes aerobiosis/hypoxia. Besides, KIRox1p expression only partially represses ScANB1 in S. cerevisioe and does not regulate the ScANB1 and KIHEM13 promoters in K. lactis. KIRox1p does not interact either with KITup1p or KISsn6p or with their homologues ScTup1p and ScSsn6p, which are components of the general co-repressor factor that mediates the transcriptional repression exerted by ScRox1p in S. cerevisiae. We have found that KIROX1 mediates the response to arsenate and cadmium and, in the presence of cadmium, it is necessary for KlYCF1 expression, a gene encoding a protein with homology to the yeast cadmium and arsenite vacuolar transporter. EMSA assays show that KIRox1p binds, through its HMG domain, to a DNA sequence present in the KlYCF1 promoter. Although in S. cerevisioe the function of ScRox1p in cadmium resistance was already known and linked to regulation of ScFET4 expression, we have found that ScRox1p also regulates ScYCF1transcription and binds to its promoter. 2012 (C) Elsevier B.V. All rights reserved. |
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