Yeast Carbon Catabolite Repression
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TLDR
It is possible in certain cases to propose a partial model of the way in which the different elements involved in catabolite repression may be integrated, and preliminary evidence suggests that Snf1 is in a dephosphorylated state under these conditions.Abstract:
Glucose and related sugars repress the transcription of genes encoding enzymes required for the utilization of alternative carbon sources; some of these genes are also repressed by other sugars such as galactose, and the process is known as catabolite repression. The different sugars produce signals which modify the conformation of certain proteins that, in turn, directly or through a regulatory cascade affect the expression of the genes subject to catabolite repression. These genes are not all controlled by a single set of regulatory proteins, but there are different circuits of repression for different groups of genes. However, the protein kinase Snf1/Cat1 is shared by the various circuits and is therefore a central element in the regulatory process. Snf1 is not operative in the presence of glucose, and preliminary evidence suggests that Snf1 is in a dephosphorylated state under these conditions. However, the enzymes that phosphorylate and dephosphorylate Snf1 have not been identified, and it is not known how the presence of glucose may affect their activity. What has been established is that Snf1 remains active in mutants lacking either the proteins Grr1/Cat80 or Hxk2 or the Glc7 complex, which functions as a protein phosphatase. One of the main roles of Snf1 is to relieve repression by the Mig1 complex, but it is also required for the operation of transcription factors such as Adr1 and possibly other factors that are still unidentified. Although our knowledge of catabolite repression is still very incomplete, it is possible in certain cases to propose a partial model of the way in which the different elements involved in catabolite repression may be integrated.read more
Citations
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Imaging and mapping protein-binding sites on DNA regulatory regions with atomic force microscopy.
TL;DR: AFM is proposed as a reliable and easy technique for identifying protein interaction sites in long DNA molecules like gene promoters and defined Mig1p as a new factor probably contributing to the carbon source-dependent transcription regulation of HXK2 gene.
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Cloning and characterization of glucokinase from a methylotrophic yeast Hansenula polymorpha: different effects on glucose repression in H. polymorpha and Saccharomyces cerevisiae.
TL;DR: Transformation of HPGLK1 into S. cerevisiae triple kinase-negative mutant DFY632 showed that H. polymorpha glucokinase cannot transmit the glucose repression signal in S.Polymorpha, and synthesis of invertase and maltase in respective transformants was insensitive to glucose repression similarly to S. Cerevisiae DFY568 possessing only glucokin enzyme.
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FLO Genes Family and Transcription Factor MIG1 Regulate Saccharomyces cerevisiae Biofilm Formation During Immobilized Fermentation.
TL;DR: An over-expression of the FLO1, 5, and 9 genes regulated by MIG1 would protect cells in the outer layer of biofilms from ethanol, a function primarily dependent on cell-cell adhesions.
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Reduced Histone Expression or a Defect in Chromatin Assembly Induces Respiration.
TL;DR: It is shown that decreased expression of histones or a defect in nucleosome assembly in the yeast Saccharomyces cerevisiae results in increased mitochondrial DNA copy numbers, oxygen consumption, ATP synthesis, and expression of genes encoding enzymes of the tricarboxylic acid cycle and oxidative phosphorylation.
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The role of the 5' untranslated region (UTR) in glucose-dependent mRNA decay.
TL;DR: It is shown that the SDH1 and SUC2 5′UTRs are capable of conferring glucose‐sensitive mRNA instability and changes in mRNA stability are correlated with changes in translational efficiency for these transcripts.
References
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TL;DR: A model is proposed to account for the synthesis and regulation of the two forms of inverts: the larger, regulated mRNA contains the initiation codon for the signal sequence required for synthesis of the secreted, glycosylated form of invertase; the smaller, constitutively transcribed mRNA begins within the coding region of the signal sequences, resulting in synthesis ofThe intracellular enzyme.
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Characterization of the AMP-activated Protein Kinase Kinase from Rat Liver and Identification of Threonine 172 as the Major Site at Which It Phosphorylates AMP-activated Protein Kinase
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TL;DR: This finding is consistent with the recent report that the AMP-activated protein kinase kinase can slowly phosphorylate and activate calmodulin-dependentprotein kinase I, at least in vitro.