Search results for "Transferases"

Chromatin dynamics of the developmentally regulated P. lividus neural alpha tubulin gene

2011

Over 40 years ago, Allfrey and colleagues (1964) suggested that two histone modifications, namely acetylation and methylation, might regulate RNA synthesis. Nowadays it is universally accepted that activation of gene expression strictly depends on enzymatic mechanisms able to dynamically modify chromatin structure. Here, using techniques including DNaseI hypersensitive site analysis, chomatin immunoprecipitation and quantitative PCR analysis, we have analyzed the dynamics of histone post-translation modifications involved in developmentally/spatially controlled activation of the sea urchin PlTalpha2 tubulin gene. We have demonstrated that only when the PlTalpha2 core promoter chromatin is a…

Epigenetic Transcriptional Regulation of the Growth Arrest-Specific gene 1 (Gas1) in Hepatic Cell Proliferation at Mononucleosomal Resolution

2011

Background Gas1 (growth arrest-specific 1) gene is known to inhibit cell proliferation in a variety of models, but its possible implication in regulating quiescence in adult tissues has not been examined to date. The knowledge of how Gas1 is regulated in quiescence may contribute to understand the deregulation occurring in neoplastic diseases. Methodology/Principal Findings Gas1 expression has been studied in quiescent murine liver and during the naturally synchronized cell proliferation after partial hepatectomy. Chromatin immunoprecipitation at nucleosomal resolution (Nuc-ChIP) has been used to carry out the study preserving the in vivo conditions. Transcription has been assessed at real …

Nephrotoxic and hepatotoxic effects of chromium compounds in rats

1986

The nephrotoxic, hepatotoxic and cardiotoxic actions of hexavalent chromium compounds, as well as their effects on lung, blood and circulation may contribute to the fatal outcome of chromium intoxication. Although trivalent chromium have been regarded as relatively biologically inert, there are a few salts of chromium III that have been found to be carcinogenic when inhaled, ingested or brought in contact with the tissues. Sensitive persons and industry workers have been subjects of dermatitis, respiratory tract injuries and digestive ulcers due to chromium compounds. In this work, the authors have studied the effect of trivalent and hexavalent chromium compounds on rats measuring the trans…

Physiological and molecular analysis of the maturation process in fruits of Clementine Mandarin and one of its late-ripening mutants

2009

Peel color is one of the main features affecting citrus quality. Clementine is a widespread citrus species with several mutants showing a delay in pigmentation and harvesting. This work characterizes the fruit development and ripening of two clementine clones, 'Comune', a widespread variety, and one of its natural mutations, 'Tardivo', which differ by a delayed color-break and extended harvest period. Morphological, chemical, and molecular analyses were carried out on fruits of both genotypes during the whole maturation process. Analysis showed that mutation did not affect ripening characteristics such as juice acidity and TSS. However, biochemical and molecular analysis revealed marked dif…

Large clostridial cytotoxins — a family of glycosyltransferases modifying small GTP-binding proteins

1996

Some Clostridium species produce AB x -type protein cytotoxins of high molecular weight. These toxins constitute the group of large clostridial cytotoxins (LCTs), which have homologous protein sequences, exert glycosyltransferase activity and modify GTP-binding proteins of the Ras-superfamily. These characteristics render the LCTs valuable tools for developmental and cell biologists.

Changes in membrane lipid composition in ethanol- and acid-adapted Oenococcus oeni cells: characterization of the cfa gene by heterologous complement…

2008

International audience; Cyclopropane fatty acid (CFA) synthesis was investigated in Oenococcus oeni. The data obtained demonstrated that acid-grown cells or cells harvested in the stationary growth phase showed changes in fatty acid composition similar to those of ethanol-grown cells. An increase of the CFA content and a decrease of the oleic acid content were observed. The biosynthesis of CFAs from unsaturated fatty acid phospholipids is catalysed by CFA synthases. Quantitative real-time-PCR experiments were performed on the cfa gene of O. oeni, which encodes a putative CFA synthase. The level of cfa transcripts increased when cells were harvested in stationary phase and when cells were gr…

Cyclopropanation of Membrane Unsaturated Fatty Acids Is Not Essential to the Acid Stress Response of Lactococcus lactis subsp. cremoris

2011

ABSTRACT Cyclopropane fatty acids (CFAs) are synthetized in situ by the transfer of a methylene group from S -adenosyl- l -methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacterium Lactococcus lactis MG1363. A mutant of the cfa gene was constructed by allelic exchange. The cfa gene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the comple…

Intracellular location of DNA nucleotidyltransferase.

1962

A loop involving NRF2, miR‐29b‐1‐5p and AKT, regulates cell fate of MDA‐MB‐231 triple‐negative breast cancer cells

2019

The present study shows that nuclear factor erythroid 2-related factor 2 (NRF2) and miR-29b-1-5p are two opposite forces which could regulate the fate of MDA-MB-231 cells, the most studied triple-negative breast cancer (TNBC) cell line. We show that NRF2 activation stimulates cell growth and markedly reduces reactive oxygen species (ROS) generation, whereas miR-29b-1-5p overexpression increases ROS generation and reduces cell proliferation. Moreover, NRF2 downregulates miR-29b-1-5p expression, whereas miR-29b-1-5p overexpression decreases p-AKT and p-NRF2. Furthermore, miR-29b-1-5p overexpression induces both inhibition of DNA N-methyltransferases (DNMT1, DNMT3A, and DNMT3B) expression and …

Dysregulation of DNA methylation induced by past arsenic treatment causes persistent genomic instability in mammalian cells

2015

The mechanisms by which arsenic-induced genomic instability is initiated and maintained are poorly understood. To investigate potential epigenetic mechanisms, in this study we evaluated global DNA methylation levels in V79 cells and human HaCaT keratinocytes at several time points during expanded growth of cell cultures following removal of arsenite exposures. We have found altered genomic methylation patterns that persisted up to 40 cell generations in HaCaT cells after the treatments were withdrawn. Moreover, mRNA expression levels were evaluated by RT-PCR for DNMT1, DNMT3A, DNMT3B, HMLH1, and HMSH2 genes, demonstrating that the down regulation of DNMT3A and DNMT3B genes, but not DNMT1, o…