Search results for "porter"

A novel SP-1 site in the human interleukin-1β promoter confers preferential transcriptional activity in keratinocytes

1996

To investigate the mechanisms of transcriptional activation of interleukin-1beta (IL-1beta) in non-monocytic cells, we constructed a series of reporter plasmids with the bacterial chloramphenicol acetyltransferase gene linked to various parts of the human IL-1beta promoter and performed transient transfection experiments. We identified a promoter segment that activates transcription most efficiently in keratinocytes. Electrophoretic mobility shift assays (EMSA) with a 43-mer oligonucleotide derived from the functionally identified cis-acting element revealed specific complexes. By competition analysis with transcription factor consensus sequence oligonucleotides and by immunosupershift, tra…

A GFP-tagged Muscleblind C protein isoform reporter construct

2010

Drosophila muscleblind (mbl), the ortholog of human Muscleblind-like 1 (MBNL1) gene involved in Myotonic Dystrophy (DM), gives raise to protein isoforms MblA to G. The specific functions and subcellular distribution of isoforms are still largely unknown. To overcome the lack of isoform-specific antibodies we generated transgenic flies that express a GFP:MblC fusion protein under the control of the Gal4/UAS system. The reporter fusion protein was able to functionally complement mbl loss of function mutations, demonstrating activity, and accumulated predominantly in adult muscle nuclei. The fluorescent nature of the reporter makes it appropriate for live imaging detection of MblC protein isof…

Identification of new P-glycoprotein inhibitors derived from cardiotonic steroids

2014

P-glycoprotein (ABCB1, MDR1) is capable of extruding chemotherapeutics outside the cell and its overexpression in certain cancer cells may cause failure of chemotherapy. Many attempts were carried out to identify potent inhibitors of this transporter and numerous compounds were shown to exert inhibitory effects in vitro, but so far none were able to make their way to the clinic due to serious complications. Natural compounds represent a great source of therapeutics, which are believed to be safe and effective. Therefore, we have screened a large library of naturally occurring cardiotonic steroids and their derivatives using high throughput flow cytometry. We were able to identify six compou…

Multiparametric evaluation of the cytoprotective effect of the Mangifera indica L. stem bark extract and mangiferin in HepG2 cells.

2012

Abstract Objective Mango (Mangifera indica L.) stem bark extract (MSBE) is a natural product with biological properties and mangiferin is the major component. This paper reported the evaluation of the protective effects of MSBE and mangiferin against the toxicity induced in HepG2 cells by tert-butyl hydroperoxide or amiodarone. Method Nuclear morphology, cell viability, intracellular calcium concentration and reactive oxygen species (ROS) production were measured by using a high-content screening multiparametric assay. Key findings MSBE and mangiferin produced no toxicity below 500 mg/ml doses. A marked recovery in cell viability, which was reduced by the toxicants, was observed in cells pr…

Vitamin E transport, membrane incorporation and cell metabolism: Is α-tocopherol in lipid rafts an oar in the lifeboat?

2010

International audience; Vitamin E is composed of closely related compounds, including tocopherols and tocotrienols. Studies of the last decade provide strong support for a specific role of alpha-tocopherol in cell signalling and the regulation of gene expression. It produces significant effects on inflammation, cell proliferation and apoptosis that are not shared by other vitamin E isomers with similar antioxidant properties. The different behaviours of vitamin E isomers might relate, at least in part, to the specific effects they exert at the plasma membrane. alpha-Tocopherol is not randomly distributed throughout the phospholipid bilayer of biological membranes, and as compared with other…

TGF-β superfamily signaling is essential for tooth and hair morphogenesis and differentiation

2007

Members of the transforming growth factor beta (TGF-beta) superfamily of signaling molecules are involved in the regulation of many developmental processes that involve the interaction between mesenchymal and epithelial tissues. Smad7 is a potent inhibitor of many members of the TGF-beta family, notably TGF-beta and activin. In this study, we show that embryonic overexpression of Smad7 in stratified epithelia using a keratin 5 promoter, results in severe morphogenetic defects in skin and teeth and leads to embryonic and perinatal lethality. To further analyze the functions of Smad7 in epithelial tissues of adult mice, we used an expression system that allowed a controlled overexpression of …

Differential expression levels of Sox9 in early neocortical radial glial cells regulate the decision between stem cell maintenance and differentiation

2021

ABSTRACTRadial glial progenitor cells (RGCs) in the dorsal forebrain directly or indirectly produce excitatory projection neurons and macroglia of the neocortex. Recent evidence shows that the pool of RGCs is more heterogeneous than originally thought and that progenitor subpopulations can generate particular neuronal cell types. Using single cell RNA sequencing, we have studied gene expression patterns of two subtypes of RGCs that differ in their neurogenic behavior. One progenitor type rapidly produces postmitotic neurons, whereas the second progenitor remains relatively quiescence before generating neurons. We have identified candidate genes that are differentially expressed between thes…

Collective Viral Spread Mediated by Virion Aggregates Promotes the Evolution of Defective Interfering Particles

2020

Recent insights have revealed that viruses use a highly diverse set of strategies to release multiple viral genomes into the same target cells, allowing the emergence of beneficial, but also detrimental, interactions among viruses inside infected cells. This has prompted interest among microbial ecologists and evolutionary biologists in studying how collective dispersal impacts the outcome of viral infections. Here, we have used vesicular stomatitis virus as a model system to study the evolutionary implications of collective dissemination mediated by viral aggregates, since this virus can spontaneously aggregate in the presence of saliva. We find that saliva-driven aggregation has a dual ef…

GABA: Receptors, transporters and metabolism

1996

Effect of changes in the cellular energy state on glucose transport activity in Brevibacterium flavum

2000

Abstract The effect of changes in cellular energy state on 6[14C]glucose uptake and activity of the phosphoenolpyruvate:glucose phosphotransferase system (PTS) in Brevibacterium flavum RC 115 cells was investigated. Energy generation in cells was varied by adding an inhibitor of cellular respiration (potassium cyanide) and an uncoupler of oxidative phosphorylation (pentachlorophenol) to the cell culture as well as by changing thiamine concentration in the bacterial growth medium. The results showed that glucose uptake in ‘respiring’ cells was inversely correlated with bacterial respiration activity: uptake declined with excess ATP generation and increased with lower ATP synthesis caused by …