Search results for "Promoter"
showing 10 items of 584 documents
miR-20b modulates VEGF expression by targeting HIF-1 alpha and STAT3 in MCF-7 breast cancer cells.
2010
MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of different genes, including genes involved in cancer progression. A functional link between hypoxia, a key feature of the tumor microenvironment, and miRNA expression has been documented. We investigated whether and how miR-20b can regulate the expression of vascular endothelial growth factor (VEGF) in MCF-7 breast cancer cells under normoxic and hypoxia-mimicking conditions (CoCl(2) exposure). Using immunoblotting, ELISA, and quantitative real-time PCR, we demonstrated that miR-20b decreased VEGF protein levels at 4 and 24 h following CoCl(2) treatment, and VEGF mRNA at 4 h of treatment. In addition, miR-20b reduce…
The interleukin-22/STAT3 pathway potentiates expression of inducible nitric-oxide synthase in human colon carcinoma cells.
2007
Inducible nitric-oxide synthase (iNOS) has been identified as a marker and mediator of disease in human colonic inflammation and carcinogenesis. Accordingly, identification of mediators that trigger iNOS in colon carcinoma/epithelial cells is an important topic of current research. Here we demonstrate that interleukin (IL)-22, a newly described member of the IL-10 cytokine family, potently synergizes with interferon (IFN)-gamma for iNOS expression in human DLD-1 colon carcinoma cells. Detection of both IL-22 receptor chains and STAT3 phosphorylation proved robust IL-22 responsiveness of these cells. Short interfering RNA technology identified STAT3 as being crucial for up-regulation of iNOS…
The budding yeast Start repressor Whi7 differs in regulation from Whi5, emerging as a major cell cycle brake in response to stress
2020
ABSTRACT Start is the main decision point in the eukaryotic cell cycle at which cells commit to a new round of cell division. It involves the irreversible activation of a transcriptional programme through the inactivation of Start transcriptional repressors: the retinoblastoma family in mammals, or Whi5 and its recently identified paralogue Whi7 (also known as Srl3) in budding yeast. Here, we provide a comprehensive comparison of Whi5 and Whi7 that reveals significant qualitative differences. Indeed, the expression, subcellular localization and functionality of Whi7 and Whi5 are differentially regulated. Importantly, Whi7 shows specific properties in its association with promoters not share…
A new chromosomal rearrangement improves the adaptation of wine yeasts to sulfite
2019
Sulfite‐generating compounds are widely used during winemaking as preservatives because of its antimicrobial and antioxidant properties. Thus, wine yeast strains have developed different genetic strategies to increase its sulfite resistance. The most efficient sulfite detoxification mechanism in Saccharomyces cerevisiae uses a plasma membrane protein called Ssu1 to efflux sulfite. In wine yeast strains, two chromosomal translocations (VIIItXVI and XVtXVI) involving the SSU1 promoter region have been shown to upregulate SSU1 expression and, as a result, increase sulfite tolerance. In this study, we have identified a novel chromosomal rearrangement that triggers wine yeast sulfite adaptation.…
The MAPK Hog1 recruits Rpd3 histone deacetylase to activate osmoresponsive genes
2003
Regulation of gene expression by mitogen-activated protein kinases (MAPKs) is essential for proper cell adaptation to extracellular stimuli. Exposure of yeast cells to high osmolarity results in rapid activation of the MAPK Hog1, which coordinates the transcriptional programme required for cell survival on osmostress. The mechanisms by which Hog1 and MAPKs in general regulate gene expression are not completely understood, although Hog1 can modify some transcription factors. Here we propose that Hog1 induces gene expression by a mechanism that involves recruiting a specific histone deacetylase complex to the promoters of genes regulated by osmostress. Cells lacking the Rpd3-Sin3 histone deac…
The C-terminal region of the Hot1 transcription factor binds GGGACAAA-related sequences in the promoter of its target genes
2015
Response to hyperosmotic stress in the yeast Saccharomyces cerevisiae involves the participation of the general stress response mediated by Msn2/4 transcription factors and the HOG pathway. One of the transcription factors activated through this pathway is Hot1, which contributes to the control of the expression of several genes involved in glycerol synthesis and flux, or in other functions related to adaptation to adverse conditions. This work provides new data about the interaction mechanism of this transcription factor with DNA. By means of one-hybrid and electrophoretic mobility assays, we demonstrate that the C-terminal region, which corresponds to amino acids 610-719, is the DNA-bindi…
Trx2p-dependent Regulation of Saccharomyces cerevisiae Oxidative Stress Response by the Skn7p Transcription Factor under Respiring Conditions
2013
The whole genome analysis has demonstrated that wine yeasts undergo changes in promoter regions and variations in gene copy number, which make them different to lab strains and help them better adapt to stressful conditions during winemaking, where oxidative stress plays a critical role. Since cytoplasmic thioredoxin II, a small protein with thiol-disulphide oxidoreductase activity, has been seen to perform important functions under biomass propagation conditions of wine yeasts, we studied the involvement of Trx2p in the molecular regulation of the oxidative stress transcriptional response on these strains. In this study, we analyzed the expression levels of several oxidative stress-related…
A short-range gradient of histone H3 acetylation and Tup1p redistribution at the promoter of the Saccharomyces cerevisiae SUC2 gene.
2003
Chromatin immunoprecipitation assays are used to map H3 and H4 acetylation over the promoter nucleosomes and the coding region of the Saccharomyces cerevisiae SUC2 gene, under repressed and derepressed conditions, using wild type and mutant strains. In wild type cells, a high level of H3 acetylation at the distal end of the promoter drops sharply toward the proximal nucleosome that covers the TATA box, a gradient that become even steeper on derepression. In contrast, substantial H4 acetylation shows no such gradient and extends into the coding region. Overall levels of both H3 and H4 acetylation rise on derepression. Mutation of GCN5 or SNF2 lead to substantially reduced SUC2 expression; in…
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…
Depletion of polyubiquitin encoded by the UBI4 gene confers pleiotropic phenotype to Candida albicans cells.
2003
We have studied the roles of polyubiquitin in Candida albicans physiology. Heterologous expression of the C. albicans polyubiquitin (UBI4) gene in a ubi4 Saccharomyces cerevisiae strain suppressed the mutant phenotype (hypersensitivity to heat shock). A heterozygous strain UBI4/Deltaubi4::hisG, obtained following the ura-blaster procedure, was used to construct a conditional mutant using a pCaDis derivative plasmid. By serendipity we isolated the UBI4 conditional mutant as well as a UBI4 mutant containing a non-functional MET3 promoter. Depletion of polyubiquitin conferred pleiotropic effects to mutant cells: (i) a limited increased sensitivity to mild heat shock; (ii) increased formation o…