Search results for "Transcription"
showing 10 items of 2278 documents
Impact of High pH Stress on Yeast Gene Expression: A Comprehensive Analysis of mRNA Turnover During Stress Responses.
2015
Environmental alkalinisation represents a stress condition for yeast Saccharomyces cerevisiae, to which this organism responds with extensive gene expression remodelling. We show here that alkaline pH causes an overall decrease in the transcription rate (TR) and a fast destabilisation of mRNAs, followed by a more prolonged stabilisation phase. In many cases, augmented mRNA levels occur without the TR increasing, which can be attributed to mRNA stabilisation. In contrast, the reduced amount of mRNAs is contributed by both a drop in the TR and mRNA stability. A comparative analysis with other forms of stress shows that, unlike high pH stress, heat-shock, osmotic and oxidative stresses present…
Specific Defects in Different Transcription Complexes Compensate for the Requirement of the Negative Cofactor 2 Repressor in Saccharomyces cerevisiae
2007
Abstract Negative cofactor 2 (NC2) has been described as an essential and evolutionarily conserved transcriptional repressor, although in vitro and in vivo experiments suggest that it can function as both a positive and a negative effector of transcription. NC2 operates by interacting with the core promoter and components of the basal transcription machinery, like the TATA-binding protein (TBP). In this work, we have isolated mutants that suppress the growth defect caused by the depletion of NC2. We have identified mutations affecting components of three different complexes involved in the control of basal transcription: the mediator, TFIIH, and RNA pol II itself. Mutations in RNA pol II in…
Phylogenetic origin and transcriptional regulation at the post-diauxic phase of SPI1, in Saccharomyces cerevisiae
2012
15 pages, 4 figures, supplementary material
A DNA region ofTorulaspora delbrueckii containing theHIS3 gene: sequence, gene order and evolution
2003
We cloned a genomic DNA fragment of the yeast Torulaspora delbrueckii by complementation of a Saccharomyces cerevisiae his3 mutant strain. DNA sequence analysis revealed that the fragment contained two complete ORFs, which share a high similarity with S. cerevisiae His3p and Mrp51p, respectively. The cloned TdHIS3 gene fully complemented the his3 mutation of S. cerevisiae, confirming that it encodes for the imidazoleglycerol-phosphate dehydrate of T. delbrueckii. Two additional ORFs, with a high homology to S. cerevisiae PET56 and DED1 genes, were mapped upstream and downstream from TdHIS3 and TdMRP51, respectively. This genetic organization is analogous to that previously found in Saccharo…
The distribution of active RNA polymerase II along the transcribed region is gene-specific and controlled by elongation factors.
2010
In order to study the intragenic profiles of active transcription, we determined the relative levels of active RNA polymerase II present at the 3'- and 5'-ends of 261 yeast genes by run-on. The results obtained indicate that the 3'/5' run-on ratio varies among the genes studied by over 12 log(2) units. This ratio seems to be an intrinsic characteristic of each transcriptional unit and does not significantly correlate with gene length, G + C content or level of expression. The correlation between the 3'/5' RNA polymerase II ratios measured by run-on and those obtained by chromatin immunoprecipitation is poor, although the genes encoding ribosomal proteins present exceptionally low ratios in …
Hyperphosphorylation of Msn2p and Msn4p in response to heat shock and the diauxic shift is inhibited by cAMP in Saccharomyces cerevisiae.
2000
In response to various stresses, as well as during the diauxic transition, the Msn2p and Msn4p transcription factors of Saccharomyces cerevisiae are activated and induce a large set of genes. This activation is inhibited by the Ras/cAMP/PKA (cAMP-dependent protein kinase) pathway. Here we show by immunoblotting experiments that Msn2p and Msn4p are phosphorylated in vivo during growth on glucose, and become hyperphosphorylated at the diauxic transition and upon heat shock. This hyperphosphorylation is correlated with activation of Msn2/4p-dependent transcription. An increased level of cAMP prevents and reverses these hyperphosphorylations, indicating that kinases other than PKA are involved.…
Hif1 Is a Component of Yeast Histone Acetyltransferase B, a Complex Mainly Localized in the Nucleus
2004
Hat1 is the catalytic subunit of the only type B histone acetyltransferase known (HAT-B). The enzyme specifically acetylates lysine 12, and to a lesser extent lysine 5, of free, non-chromatin-bound histone H4. The complex is usually isolated with cytosolic fractions and is thought to be involved in chromatin assembly. The Saccharomyces cerevisiae HAT-B complex also contains Hat2, a protein stimulating Hat1 catalytic activity. We have now identified by two-hybrid experiments Hif1 as both a Hat1- and a histone H4-interacting protein. These interactions were dependent on HAT2, indicating a mediating role for Hat2. Biochemical fractionation and co-immunoprecipitation assays demonstrated that Hi…
Loss of Anticodon Wobble Uridine Modifications Affects tRNALys Function and Protein Levels in Saccharomyces cerevisiae
2015
In eukaryotes, wobble uridines in the anticodons of tRNA(Lys)UUU, tRNA(Glu)UUC and tRNA(Gln)UUG are modified to 5-methoxy-carbonyl-methyl-2-thio-uridine (mcm5s2U). While mutations in subunits of the Elongator complex (Elp1-Elp6), which disable mcm5 side chain formation, or removal of components of the thiolation pathway (Ncs2/Ncs6, Urm1, Uba4) are individually tolerated, the combination of both modification defects has been reported to have lethal effects on Saccharomyces cerevisiae. Contrary to such absolute requirement of mcm5s2U for viability, we demonstrate here that in the S. cerevisiae S288C-derived background, both pathways can be simultaneously inactivated, resulting in combined los…
The total mRNA concentration buffering system in yeast is global rather than gene-specific
2021
Gene expression in eukaryotes does not follow a linear process from transcription to translation and mRNA degradation. Instead it follows a circular process in which cytoplasmic mRNA decay crosstalks with nuclear transcription. In many instances, this crosstalk contributes to buffer mRNA at a roughly constant concentration. Whether the mRNA buffering concept operates on the total mRNA concentration or at the gene-specific level, and if the mechanism to do so is a global or a specific one, remain unknown. Here we assessed changes in mRNA concentrations and their synthesis rates along the transcriptome of aneuploid strains of the yeast Saccharomyces cerevisiae. We also assessed mRNA concentra…
Acid trehalase is involved in intracellular trehalose mobilization during postdiauxic growth and severe saline stress in Saccharomyces cerevisiae.
2008
The role of the acid trehalase encoded by the ATH1 gene in the yeast Saccharomyces cerevisiae is still unclear. In this work, we investigated the regulation of ATH1 transcription and found a clear involvement of the protein kinase Hog1p in the induction of this gene under severe stress conditions, such as high salt. We also detected changes in the acid trehalase activity and trehalose levels, indicating a role of the acid trehalase in intracellular trehalose mobilization. Finally, the growth analysis for different mutants in neutral and acid trehalases after high salt stress implicates acid trehalase activity in saline stress resistance.