Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been considered that three key elements participate in nitrogen catabolite repression (NCR) of Saccharomyces cerevisiae: the GLN3 and GAT1/NIL1-encoded transcriptional activators and their negative regulator Ure2. The fact that expression of various NCR-sensitive genes is not derepressed in the absence of Ure2 has led to the proposition that there must exist a protein with a similar function to that of Ure2. The results presented in this paper show that various NCR-sensitive genes are derepressed through GLN3-mediated transcriptional activation in a gcn4Delta mutant. This effect is additive to that exerted by the lack of Ure2 and to that evoked in rapamycin-treated cultures. Our results uncover the fact that NCR is not solely achieved through the action of Gln3, Gat1, and Ure2. Since Gcn4 regulates the expression of a broad spectrum of genes, the lack of this transcriptional activator could prevent the expression of a potential Gln3 antagonist. Alternatively, Gcn4 could directly hinder Gln3 functioning.
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PMID:Gcn4 negatively regulates expression of genes subjected to nitrogen catabolite repression. 1455 39

The 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. In this paper, we show that the GAT1 gene, encoding a transcriptional activator of nitrogen-responsive catabolic genes, produces a variety of mRNAs differing in their 5' and 3' termini. Alternative transcription initiation leads to the constitutive, low level production of 2 full length proteins differing in their N-termini, whereas premature transcriptional termination generates a short, highly nitrogen catabolite repression- (NCR-) sensitive transcript that, as far as we can determine, is not translated under the growth conditions we used, but rather likely protects the cell from excess Gat1.
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PMID:Premature termination of GAT1 transcription explains paradoxical negative correlation between nitrogen-responsive mRNA, but constitutive low-level protein production. 2690 98

We studied adaptive evolution of gene expression using long-term experimental evolution of Saccharomyces cerevisiae in ammonium-limited chemostats. We found repeated selection for non-synonymous variation in the DNA binding domain of the transcriptional activator, GAT1, which functions with the repressor, DAL80 in an incoherent type-1 feedforward loop (I1-FFL) to control expression of the high affinity ammonium transporter gene, MEP2. Missense mutations in the DNA binding domain of GAT1 reduce its binding to the GATAA consensus sequence. However, we show experimentally, and using mathematical modeling, that decreases in GAT1 binding result in increased expression of MEP2 as a consequence of properties of I1-FFLs. Our results show that I1-FFLs, one of the most commonly occurring network motifs in transcriptional networks, can facilitate adaptive tuning of gene expression through modulation of transcription factor binding affinities. Our findings highlight the importance of gene regulatory architectures in the evolution of gene expression.
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PMID:An incoherent feedforward loop facilitates adaptive tuning of gene expression. 2962 May 23