Functional characterization of KlHAP1: A model to foresee different mechanisms of transcriptional regulation by Hap1p in yeasts

Lamas-Maceiras, Mónica; Núñez, Laura; Rodrı́guez-Belmonte, Esther; González-Siso, María-Isabel; Cerdán, M. Esperanza

doi:10.1016/j.gene.2007.09.012

Cited by 18 publications

(20 citation statements)

References 68 publications

(82 reference statements)

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“…For many genes, we observed the regulation only under hypoxic conditions. In aerobiosis, they are less regulated by KlHAP1, an observation also reported in a recent paper (35). On the other hand, some other genes such as KlEEB1 (KlEHT1), RAG1, and HGT1, orthologs of which have not been reported as Hap1p-regulated targets in S. cerevisiae, are in turn under the control of KlHap1p in K. lactis.…”

Section: Discussionsupporting

confidence: 66%

Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis

et al. 2008

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The HAP1 (CYP1) gene product of Saccharomyces cerevisiae is known to regulate the transcription of many genes in response to oxygen availability. This response varies according to yeast species, probably reflecting the specific nature of their oxidative metabolism. It is suspected that a difference in the interaction of Hap1p with its target genes may explain some of the species-related variation in oxygen responses. As opposed to the fermentative S. cerevisiae, Kluyveromyces lactis is an aerobic yeast species which shows different oxygen responses. We examined the role of the HAP1-equivalent gene (KlHAP1) in K. lactis. KlHap1p showed a number of sequence features and some gene targets (such as KlCYC1) in common with its S. cerevisiae counterpart, and KlHAP1 was capable of complementing the hap1 mutation. However, the KlHAP1 disruptant showed temperature-sensitive growth on glucose, especially at low glucose concentrations. At normal temperature, 28°C, the mutant grew well, the colony size being even greater than that of the wild type. The most striking observation was that KlHap1p repressed the expression of the major glucose transporter gene RAG1 and reduced the glucose uptake rate. This suggested an involvement of KlHap1p in the regulation of glycolytic flux through the glucose transport system. The ⌬Klhap1 mutant showed an increased ability to produce ethanol during aerobic growth, indicating a possible transformation of its physiological property to Crabtree positivity or partial Crabtree positivity. Dual roles of KlHap1p in activating respiration and repressing fermentation may be seen as a basis of the Crabtree-negative physiology of K. lactis.In both prokaryotes and eukaryotes, the transcription of many genes is controlled by oxygen availability. This regulation has been extensively studied in Saccharomyces cerevisiae. However, this species is rather exceptional among yeasts because of its extreme fermentation-oriented physiology. Other species that have comparable sets of genes in their genomes (45) conspicuously differ from S. cerevisiae in their mode of carbon metabolism in general and in their response to oxygen in particular. The difference may reflect evolutionary variation of the regulatory networks that characterize each species. In the present work, an aerobic species, Kluyveromyces lactis, was chosen for a comparative study of oxygen-linked regulation. The genomic sequence of this yeast is entirely known (EMBL accession numbers CR3821121 to CR382126), and its carbon metabolism is well documented (7,8,51).In S. cerevisiae, the transcriptional activator Hap1p is involved in cell response to oxygen via heme (25). A number of genes appear to be targets of this regulator, but the range and mode of these interactions are only partially known. In S. cerevisiae, oxygen-regulated genes are of two kinds: the "aerobic genes," which are activated under aerobic conditions, and the "hypoxic genes," which are fully expressed only under anoxic or hypoxic conditions and repressed by oxygen. This regulation occu...

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Section: Discussionsupporting

confidence: 66%

Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis

et al. 2008

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“…The expression of KlHEM1 is clearly promoted by hypoxia (Nú ñez et al, 2008). The transcriptional regulator KlHap1 is also expressed in an oxygendependent fashion but its role in respiratory and/or fermentative carbon metabolism is still to be elucidated (Lamas-Maceiras et al, 2007;Bao et al, 2008). A large-scale transcriptional analysis of about 60 K. lactis genes that are putatively oxygen-dependent (Blanco et al, 2007) indicated that the hypoxic response of this yeast is very different from S. cerevisiae and limited to very few ORFs, namely KLLA0A09075g (OYE2), KLLA0C05566g (OLE1) and KLLA0F14058g (GSH1).…”

Section: Introductionmentioning

confidence: 99%

A dual signalling pathway for the hypoxic expression of lipid genes, dependent on the glucose sensor Rag4, is revealed by the analysis of the KlMGA2 gene in Kluyveromyces lactis

et al. 2012

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A dual signalling pathway for the hypoxic expression of lipid genes, dependent on the glucose sensor Rag4, is revealed by the analysis of the KlMGA2 gene in Kluyveromyces lactis In the respiratory yeast Kluyveromyces lactis, little is known about the factors regulating the metabolic response to oxygen shortage. After searching for homologues of characterized Saccharomyces cerevisiae regulators of the hypoxic response, we identified a gene that we named KlMGA2, which is homologous to MGA2. The deletion of KlMGA2 strongly reduced both the fermentative and respiratory growth rate and altered fatty acid composition and the unsaturation index of membranes. The reciprocal heterologous expression of MGA2 and KlMGA2 in the corresponding deletion mutant strains suggested that Mga2 and KlMga2 are functional homologues. KlMGA2 transcription was induced by hypoxia and the glucose sensor Rag4 mediated the hypoxic induction of KlMGA2. Transcription of lipid biosynthetic genes KlOLE1, KlERG1, KlFAS1 and KlATF1 was induced by hypoxia and was dependent on KlMga2, except for KlOLE1. Rag4 was required for hypoxic induction of transcription for both KlMga2-dependent (KlERG1) and KlMga2-independent (KlOLE1) structural genes.

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“…Previous studies have shown that the function of Klhap1 is different from that of Schap1. KlHap1 behaves as a direct or indirect repressor of induction of the oxidative stress response, and negatively controls the transcription of Klhem13, Klyap1, Kltsa1 and the major glucose transporter gene Klrag1 (Lamas-Maceiras et al 2007;Bao et al 2008). Considering that Hap1 is a transcriptional repressor to several genes mentioned above, the recombinant Klhap1 deleted strain was constructed to investigate its effect on heterologous inulinase expression.…”

Section: Inulinase-expressing Plasmid Stabilitymentioning

confidence: 99%

“…In S. cerevisiae, Hap1 is a zinc finger transcription factor which activates transcription of genes required for respiration and for controlling oxidative damage in response to levels of heme and oxygen (Zhang and Hach 1999). The role of Hap1 in K. lactis has not been clearly elucidated, but there are notable differences between the function of Hap1 from S. cerevisiae and its homologue from k. lactis (Lamas-Maceiras et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Enhanced expression of heterologous inulinase in Kluyveromyces lactis by disruption of hap1 gene

Jiang

Fang

et al. 2009

Biotechnol Lett

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Inulinase gene (Kcinu) derived from Kluyveromyces cicerisporus was expressed extracellularly in Kluyveromyces lactis using an episomal vector directed by Kcinu promoter. The influence of hap1 gene disruption on the expression of inulinase was studied. Inulinase activity in the supernatant of the recombinant Klhap1Delta strain was 391 U ml(-1) after cultured 120 h, which was 2.2-fold that of the wild type host. The relative inulinase mRNA level of the Klhap1Delta strain was 11.3-fold that of the wild type strain, and the expression plasmid was more stable in the mutant host. Based on these results, the disruption of hap1 facilitated the high and stable expression of inulinase controlled by Kcinu promoter in K. lactis.

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Functional characterization of KlHAP1: A model to foresee different mechanisms of transcriptional regulation by Hap1p in yeasts

Cited by 18 publications

References 68 publications

Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis

Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis

A dual signalling pathway for the hypoxic expression of lipid genes, dependent on the glucose sensor Rag4, is revealed by the analysis of the KlMGA2 gene in Kluyveromyces lactis

Enhanced expression of heterologous inulinase in Kluyveromyces lactis by disruption of hap1 gene

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