Nitrogen catabolite repression (NCR) is a means for yeast to adapt its transcriptome to changing nitrogen sources in its environment. In conditions of derepression (under poor nitrogen conditions, upon rapamycin treatment, or when glutamine production is inhibited), two transcriptional activators of the GATA family are recruited to NCR-sensitive promoters and activate transcription of NCR-sensitive genes. Earlier observations have involved the Spt-Ada-Gcn5 acetyltransferase (SAGA) chromatin remodeling complex in these transcriptional regulations.
View Article and Find Full Text PDFBacterial contaminations in yeast fermentation tanks are a recurring problem for the bioethanol production industry. Lactic acid bacteria (LAB), particularly of the genus Lactobacillus, are the most common contaminants. Their proliferation can reduce fermentation efficiency or even impose premature shutdown for cleaning.
View Article and Find Full Text PDFNitrogen catabolite repression (NCR) is a major transcriptional control pathway governing nitrogen use in yeast, with several hundred of target genes identified to date. Early and extensive studies on NCR led to the identification of the 4 GATA zinc finger transcription factors, but the primary mechanism initiating NCR is still unclear up till now. To identify novel players of NCR, we have undertaken a genetic screen in an NCR-relieved gdh1Δ mutant, which led to the identification of four genes directly linked to protein ubiquitylation.
View Article and Find Full Text PDFMicrobial species occupying the same ecological niche or codeveloping during a fermentation process can exchange metabolites and mutualistically influence each other's metabolic states. For instance, yeast can excrete amino acids, thereby cross-feeding lactic acid bacteria unable to grow without an external amino acid supply. The yeast membrane transporters involved in amino acid excretion remain poorly known.
View Article and Find Full Text PDFThe vacuole of the yeast Saccharomyces cerevisiae plays an important role in nutrient storage. Arginine, in particular, accumulates in the vacuole of nitrogen-replete cells and is mobilized to the cytosol under nitrogen starvation. The arginine import and export systems involved remain poorly characterized, however.
View Article and Find Full Text PDFGATA transcription factors are highly conserved among eukaryotes and play roles in transcription of genes implicated in cancer progression and hematopoiesis. However, although their consensus binding sites have been well defined in vitro, the in vivo selectivity for recognition by GATA factors remains poorly characterized. Using ChIP-Seq, we identified the Dal80 GATA factor targets in yeast.
View Article and Find Full Text PDFThe yeast Target of Rapamycin Complex 1 (TORC1) plays a central role in controlling growth. How amino acids and other nutrients stimulate its activity via the Rag/Gtr GTPases remains poorly understood. We here report that the signal triggering Rag/Gtr-dependent TORC1 activation upon amino-acid uptake is the coupled H influx catalyzed by amino-acid/H symporters.
View Article and Find Full Text PDFThe first step in executing the genetic program of a cell is production of mRNA. In yeast, almost every gene is transcribed as multiple distinct isoforms, differing at their 5' and/or 3' termini. However, the implications and functional significance of the transcriptome-wide diversity of mRNA termini remains largely unexplored.
View Article and Find Full Text PDFNitrogen catabolite repression (NCR) is the regulatory pathway through which Saccharomyces cerevisiae responds to the available nitrogen status and selectively utilizes rich nitrogen sources in preference to poor ones. Expression of NCR-sensitive genes is mediated by two transcription activators, Gln3 and Gat1, in response to provision of a poorly used nitrogen source or following treatment with the TORC1 inhibitor, rapamycin. During nitrogen excess, the transcription activators are sequestered in the cytoplasm in a Ure2-dependent fashion.
View Article and Find Full Text PDFNitrogen catabolite repression (NCR)-sensitive transcription is activated by Gln3 and Gat1. In nitrogen excess, Gln3 and Gat1 are cytoplasmic, and transcription is minimal. In poor nitrogen, Gln3 and Gat1 become nuclear and activate transcription.
View Article and Find Full Text PDFUre2 is a phosphoprotein and central negative regulator of nitrogen-responsive Gln3/Gat1 localization and their ability to activate transcription. This negative regulation is achieved by the formation of Ure2-Gln3 and -Gat1 complexes that are thought to sequester these GATA factors in the cytoplasm of cells cultured in excess nitrogen. Ure2 itself is a dimer the monomer of which consists of two core domains and a flexible protruding αcap.
View Article and Find Full Text PDFPhysiological, behavioral, cognitive, and emotional factors are generally acknowledged to play a role in premature ejaculation (PE). However, the nature and the extent of their etiological impact remain largely imprecise. The present study examined functional and psychometric dynamics at work in a PE population.
View Article and Find Full Text PDFIntroduction: Premature ejaculation (PE) is quite common. Although effective treatments do exist, only a few affected people consult a practitioner in order to overcome their problem. At the same time, studies have shown that reading didactical documents about their PE problem (bibliotherapy) can be useful to men.
View Article and Find Full Text PDFProtein phosphatase 2A (PP2A), a central Tor pathway phosphatase consisting of a catalytic subunit (Pph21 or Pph22), a scaffold subunit (Tpd3), and one of two regulatory subunits (Cdc55 or Rts1), has been repeatedly shown to play important roles in cytoplasmically localized signal transduction activities. In contrast, its involvement in intranuclear control of mRNA production has heretofore not been reported. Here, we demonstrate for the first time that binding of the nitrogen catabolite repression-responsive GATA transcription activators (Gln3 and Gat1) to the DAL5 promoter and DAL5 expression require Pph21/22-Tpd3-Cdc55/Rts1 in rapamycin-treated glutamine-grown cells.
View Article and Find Full Text PDFIn yeast, rapamycin (Rap)-inhibited TorC1, and the phosphatases it regulates (Sit4 and PP2A) are components of a conserved pathway regulating the response of eukaryotic cells to nutrient availability. TorC1 and intracellular nitrogen levels regulate the localization of Gln3 and Gat1, the activators of nitrogen catabolite repression (NCR)-sensitive genes whose products are required to utilize poor nitrogen sources. In nitrogen excess, Gln3 and Gat1 are cytoplasmic, and NCR-sensitive transcription is repressed.
View Article and Find Full Text PDFSaccharomyces cerevisiae cells are able to adapt their metabolism according to the quality of the nitrogen sources available in the environment. Nitrogen catabolite repression (NCR) restrains the yeast's capacity to use poor nitrogen sources when rich ones are available. NCR-sensitive expression is modulated by the synchronized action of four DNA-binding GATA factors.
View Article and Find Full Text PDFNitrogen catabolite repression (NCR)-sensitive genes, whose expression is highly repressed when provided with excess nitrogen and derepressed when nitrogen is limited or cells are treated with rapamycin, are routinely used as reporters in mechanistic studies of the Tor signal transduction pathway in Saccharomyces cerevisiae. Two GATA factors, Gln3 and Gat1, are responsible for NCR-sensitive transcription, but recent evidence demonstrates that Tor pathway regulation of NCR-sensitive transcription bifurcates at the level of GATA factor localization. Gln3 requires Sit4 phosphatase for nuclear localization and NCR-sensitive transcription while Gat1 does not.
View Article and Find Full Text PDFGln3, the major activator of nitrogen catabolite repression (NCR)-sensitive transcription, is often used as an assay of Tor pathway regulation in Saccharomyces cerevisiae. Gln3 is cytoplasmic in cells cultured with repressive nitrogen sources (Gln) and nuclear with derepressive ones (Pro) or after treating Gln-grown cells with the Tor inhibitor, rapamycin (Rap). In Raptreated or Pro-grown cells, Sit4 is posited to dephosphorylate Gln3, which then dissociates from a Gln3-Ure2 complex and enters the nucleus.
View Article and Find Full Text PDFThe Tor1,2 protein kinases globally influence many cellular processes including nitrogen-responsive gene expression that correlates with intracellular localization of GATA transcription activators Gln3 and Gat1/Nil1. Gln3-Myc(13) and Gat1-Myc(13) are restricted to the cytoplasm of cells provided with good nitrogen sources, e.g.
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