Search results for "Transferase"
showing 10 items of 1030 documents
Alterations of Activities of Ribonucleases and Polyadenylate Polymerase in Synchronized Mouse L Cells
1977
The activities of the three known catabolic and the one anabolic polyadenylate enzymes have been determined in synchronized L5178y cells: endoribonuclease, exoribonuclease, 5'-nucleotidase and poly(A) polymerase (Mg2+-dependent). These four enzymes were found primarily in the nuclear fraction. The activity of poly(A) polymerase remains essentially constant during the transition from G1 to S phase. However, the poly(A) catabolic enzyme activities increase parallel with DNA synthesis; the endoribonuclease activity increases 4-fold during G1 to S phase, the exoribonuclease and the nucleotidase activities increasing 30-fold and 16-fold. During the S phase the poly(A)-degrading enzymes are far m…
Effects of propanil on the European eel Anguilla anguilla and post-exposure recovery using selected biomarkers as effect criteria
2008
Abstract The aim of this study was to assess the physiological response of Anguilla anguilla to propanil and the degree of recovery after being moved to clean water. Preliminary acute toxicity test was carried out in the laboratory and the median lethal concentration (LC50) at 96 h was calculated as 31.33 mg/L (29.60–33.59 mg/L). NOEC and LOEC values (at 96 h) were also calculated as 20 and 25 mg/L, respectively. The fish were exposed to 0.63 and 3.16 mg/L of propanil for 72 h and allowed to recover for 144 h. Total proteins (TPs), γ -glutamil transpeptidase ( γ -GT), alanin aminotransferase (AlAT), alkaline phosphatase (AP), lactate dehydrogenase (LDH) and water content (WC) were assayed i…
Metazoan Circadian Rhythm: Toward an Understanding of a Light-Based Zeitgeber in Sponges
2013
In all eukaryotes, the 24-h periodicity in the environment contributed to the evolution of the molecular circadian clock. We studied some elements of a postulated circadian clock circuit in the lowest metazoans, the siliceous sponges. First, we identified in the demosponge Suberites domuncula the enzyme luciferase that generates photons. Then (most likely), the photons generated by luciferase are transmitted via the biosilica glass skeleton of the sponges and are finally harvested by cryptochrome in the same individual; hence, cryptochrome is acting as a photosensor. This information-transduction system, generation of light (luciferase), photon transmission (through the siliceous spicules),…
Insulin-like growth factor 1 differentially regulates estrogen receptor-dependent transcription at estrogen response element and AP-1 sites in breast…
2007
Cross-talk between insulin-like growth factor 1 (IGF-1) and estrogen receptor alpha (ER) regulates gene expression in breast cancer cells, but the underlying mechanisms remain unclear. Here, we studied how 17-beta-estradiol (E2) and IGF-1 affect ER transcriptional machinery in MCF-7 cells. E2 treatment stimulated ER loading on the estrogen response element (ERE) in the pS2 promoter and on the AP-1 motif in the cyclin D1 promoter. On ERE, similar amounts of liganded ER were found at 1-24-h time points, whereas on AP-1, ER binding fluctuated over time. At 1 h, liganded ER was recruited to ERE together with histone acetyltransferases SRC-1 and p300, ubiquitin ligase E6-AP, histone methyltransf…
ADR1 and SNF1 Mediate Different Mechanisms in Transcriptional Regulation of Yeast POT1 Gene
1994
We studied the consequences of adr1 and snf1 mutations on POT1 gene expression in different growth conditions. The results obtained reveal that ADR1 and SNF1 genes affect POT1 transcription in different ways: ADR1 has a minor role in derepression in low concentration of glucose but is essential for activation in stationary phase whereas SNF1 is essential for derepression and activation, although it does not seem to be directly involved in the molecular mechanism of activation in stationary phase.
A new glucose-repressible gene identified from the analysis of chromatin structure in deletion mutants of yeast SUC2 locus.
1991
We have previously shown that some changes occur in the chromatin structure of the 3' flank of the yeast SUC2 gene in going from a repressed to an active state. In an attempt to find out the causes of these changes, we have carried out experiments in which mutant copies of SUC2 locus lacking either 5' or 3' flanks have been analysed for their transcriptional activity and chromatin structure. These experiments allowed us to discard any relationship between SUC2 transcription and chromatin changes within its 3'flank. Sequencing of this flank and mRNA analysis, however, resulted in the location of a putative peroxisomal 3-oxoacyl-CoA thiolase gene (POT1), which is repressible by glucose. The d…
Annotation of microsporidian genomes using transcriptional signals
2012
EA GenoSol CT3; International audience; High-quality annotation of microsporidian genomes is essential for understanding the biological processes that govern the development of these parasites. Here we present an improved structural annotation method using transcriptional DNA signals. We apply this method to re-annotate four previously annotated genomes, which allow us to detect annotation errors and identify a significant number of unpredicted genes. We then annotate the newly sequenced genome of Anncaliia algerae. A comparative genomic analysis of A. algerae permits the identification of not only microsporidian core genes, but also potentially highly expressed genes encoding membrane-asso…
Peroxisome-proliferator-activated receptors as physiological sensors of fatty acid metabolism: molecular regulation in peroxisomes
2001
The enzymes required for the beta-oxidation of fatty acyl-CoA are present in peroxisomes and mitochondria. Administration of hypolipidaemic compounds such as clofibrate to rodents leads to an increase in the volume and density of peroxisomes in liver cells. These proliferators also induce simultaneously the expression of genes encoding acyl-CoA oxidase, enoyl-CoA hydratase-hydroxyacyl-CoA dehydrogenase (multifunctional enzyme) and thiolase (3-ketoacyl-CoA thiolase). All these enzymes are responsible for long-chain and very-long-chain fatty acid beta-oxidation in peroxisomes. Similar results were observed when rat hepatocytes, or liver-derived cell lines, were cultured with a peroxisome prol…
Sus1, a functional component of the SAGA histone acetylase complex and the nuclear pore-associated mRNA export machinery
2004
12 páginas, 7 figuras, 1 tabla. Material suplementario en: https://doi.org/10.1016/S0092-8674(03)01025-0. The SUS1 sequences have been deposited in GenBank with the accession number AY278445.
The POT1 gene for yeast peroxisomal thiolase is subject to three different mechanisms of regulation
1992
The Saccharomyces cerevisiae POT1 gene is, as are other yeast peroxisomal protein genes, inducible by fatty acids and repressible by glucose. We have now found that it is also induced during the stationary phase of the culture. To investigate these three regulatory circuits, we have studied the mRNA levels of regulatory mutants as well as the changes in chromatin structure upon gene activation. We conclude that the regulation of transcriptional activity in glucose repression, oleate induction, and stationary phase induction follow different molecular mechanisms. We suggest that this multiplicity of regulatory mechanisms may represent a general rule for the yeast peroxisomal protein genes.