Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alveolar epithelium in situ takes up luminal glucose by cotransport with sodium. Cultured alveolar type II pneumocytes have only sodium-independent glucose uptake. It is unclear which isoforms are responsible for glucose transport in these cells and why sodium-glucose cotransport activity disappears during culture. GLUT1, GLUT4, GLUT5 and SGLT1 mRNA were detected in freshly isolated rat alveolar type II cells by reverse transcriptase-polymerase chain reaction. We show that SGLT1 mRNA was 90% lower in cells cultured in plastic wells for 2 or 4 days than in freshly isolated cells. mRNAs coding for the facilitated transporters were reduced from 40% (GLUT1) and 75% (GLUT4 and GLUT5) in cultured cells. Cells cultured at the air-liquid interface better preserved their phenotype as attested by significantly higher surfactant-associated protein mRNA levels. However, these cells had no higher GLUT1 and SGLT1 gene expression. Thus, alveolar type II cells lose sodium-glucose cotransport activity in part because of a decrease in mRNA levels. These changes in gene expression and/or mRNA stability may be an additional consequence of the shift towards the type I cell phenotype observed in cultured type II pneumocytes.
...
PMID:Glucose transporter gene expression in freshly isolated and cultured rat pneumocytes. 1198

The nucleosidal reverse transcriptase inhibitors (NRTI), the protease inhibitors (PI) and the non-nucleosidal reverse transcriptase inhibitors remain the pillars of antiretroviral therapy (ART). In the spring of 2002, they were joined by a representative of a further class of substances, the nucleotidal reverse transcriptase inhibitors (NTRTI). The use of PI, but also of other substances, is associated with undesired effects, in particular on lipid and glucose metabolism. The aim of treatment is to achieve maximum reduction in the amount of virus in the blood. The question as to the timing of treatment--early or late--continues to arouse controversial discussion.
...
PMID:[Established and new drugs. Antiretroviral therapy 2002]. 1204 77

Recent functional, autoradiographic, and molecular investigations have shown that the pineal secretory product melatonin reduces the forskolin-stimulated insulin secretion from isolated pancreatic islets of neonate rats. Autoradiographic and binding studies as well as reverse transcriptase-polymerase chain reaction (RT-PCR) experiments proved that these effects are mediated through specific, high-affinity pertussis-toxin-sensitive Gi-protein-coupled MT(1) receptors and subsequent inhibition of the adenylyl cyclase/cyclic adenosine monophosphate (cAMP) system. This hypothesis was proved by blocking the intracellular signal transduction pathway using the non-hydrolyzable guanosine triphosphate analog guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) or the competitive melatonin receptor antagonist luzindole. Both GTPgammaS and luzindole diminished the melatonin effect. We have published these prior results elsewhere. So far, however, no information is available on both whether the MT1 receptors are located on the beta-cells and whether the consecutive functional reactions are based on a direct influence of melatonin on the insulin producing beta-cells. In order to examine this question, we used a glucose responsive insulin producing insulinoma cell line INS-1 isolated from rats. Comparable with the results of islets the competitive receptor antagonist luzindole diminished the insulin-decreasing effect of melatonin. In addition, our RT-PCR experiments, using specific primers for the rat melatonin receptor MT(1) showed that this melatonin receptor mRNA is also expressed in the INS-1 cells. Furthermore we radioimmunologically analyzed the forskolin-stimulated cAMP concentration in the superfusate. Similar to insulin secretion, the cAMP concentration was significantly reduced by melatonin. Following the hypothesis that cAMP is actively secreted from INS-1 cells by an energy-dependent mechanism based on either a OAT1/ROAT1 like anion exchanger or MDR-like transport systems, we used probenecid (p-[dipropylsulfamoyl] benzoic acid), a known inhibitor of cAMP extrusion. Probenecid blocks the export of cAMP by acting on transport mechanisms which are as yet not completely understood. Consistently, insulin secretion was increased and cAMP concentration diminished. The application of the phosphodiesterase inhibitor IBMX (3-isobutyl-1-methylxanthine) caused a marked rise of insulin secretion as well as cAMP concentration in the perifusate. From these data we conclude that the MT1 receptor is located on the INS-1 cell and therefore in general on pancreatic beta-cells.
...
PMID:Receptor (MT(1)) mediated influence of melatonin on cAMP concentration and insulin secretion of rat insulinoma cells INS-1. 1215 39

Human pancreatic islets are a major focus of diabetes research due to their key role in glucose homeostasis and their potential for transplantation in the treatment of type 1 diabetes. Currently, no comprehensive analysis of baseline or glucose-stimulated islet gene expression is available. Using oligonucleotide microarrays we analyzed isolated intact human islets incubated at low and high glucose. We identified approximately 6000 islet genes, several with clinical implications, as well as a number of glucose-regulated genes. Interestingly, two transforming growth factor beta (TGFbeta) superfamily members were highly regulated by glucose. One of them, PDF, was found to have a very high expression level compared to other TGFbeta superfamily members. Quantitative reverse transcriptase polymerase chain reaction confirmed these results and demonstrated that the highly expressed PDF was approximately 10-fold down- regulated by glucose while other TGFbeta superfamily members and target genes were up-regulated. These results suggest that a highly regulated TGFbeta signaling cascade exists in human islets, and that PDF may play a central role in islet biology. Since TGFbeta is involved in differentiation and immune modulation, this novel pathway may link glucose metabolism, immune response and development of human islets. We report here the first gene expression profile of intact human islets. These and similar analyses will provide better understanding of human islet biology and enhance the development of novel diabetes therapies.
...
PMID:Oligonucleotide microarray analysis of intact human pancreatic islets: identification of glucose-responsive genes and a highly regulated TGFbeta signaling pathway. 1219 86

Human cells acquire vitamin C using two different transporter systems, the sodium-ascorbic acid co-transporters with specificity for ascorbic acid, and the facilitative glucose transporters with specificity for dehydroascorbic acid. There is no information on the mechanism of vitamin C transport across the intestinal barrier, a step that determines the bioavailability of vitamin C in humans. We used the colon carcinoma cell line CaCo-2 as an in vitro model for vitamin C transport in enterocyte-like cells. The results of transport kinetics, sodium dependence, inhibition studies, and reverse transcriptase-PCR analysis indicated that CaCo-2 cells express the sodium-ascorbate co-transporters SVCT1 and SVCT2, the dehydroascorbic acid transporters GLUT1 and GLUT3, and a third dehydroascorbic acid transporter with properties expected for GLUT2. Analysis by real time quantitative PCR revealed that the post-confluent differentiation of CaCo-2 cells was accompanied by a marked increase (4-fold) in the steady-state level of SVCT1 mRNA, without changes in SVCT2 mRNA levels. Functional studies revealed that the differentiated cells expressed only one functional ascorbic acid transporter having properties expected for SVCT1, and transported ascorbic acid with a V(max) that was increased at least 2-fold compared with pre-confluent cells. Moreover, post-confluent Caco-2 cells growing as monolayers in permeable filter inserts showed selective sorting of SVCT1 to the apical membrane compartment, without functional evidence for the expression of SVCT2. The identification of SVCT1 as the transporter that allows vectorial uptake of ascorbic acid in differentiated CaCo-2 cells has a direct impact on our understanding of the mechanism for vitamin C transport across the intestinal barrier.
...
PMID:Up-regulation and polarized expression of the sodium-ascorbic acid transporter SVCT1 in post-confluent differentiated CaCo-2 cells. 1238 35

Preterm infants lack adequate surfactant production and often require oxygen support for adequate oxygenation. Prolonged oxygen treatment leads to the development of bronchopulmonary dysplasia (BPD), a disease process characterized by the blunting of alveolarization and proliferation of myofibroblasts. In the present study, we investigated metabolic adaptive changes in cultured fibroblasts isolated from immature (d18) and near-term (d21), fetal rat lungs in response to normoxic (21%) and hyperoxic (95%) exposures. We used the [1,2-13C2]D-glucose tracer and gas chromatography/mass spectrometry to characterize glucose carbon redistribution between the nucleic acid ribose, lactate, and palmitate synthetic pathways, and reverse transcriptase-polymerase chain reaction to assess adipose differentiation related protein (ADRP) mRNA expression in response to hyperoxic exposure. Exposure to hyperoxia at each passage caused decrease (*, p<0.05 vs. 21% O2) in ADRP mRNA expression in the d18 fibroblasts. This passage-dependent transdifferentiation is accompanied by a moderate (9-20%) increase in the synthesis of nucleic acid ribose from glucose through the non-oxidative steps of the pentose cycle. In contrast, d18 fibroblasts showed over an 85% decrease in the de novo synthesis of palmitate from glucose, while d21 fibroblasts showed a less pronounced 32-38% decrease in de novo lipid synthesis in hyperoxia-exposed cultures. It can be concluded from these studies that: (1) there is a maturation dependent sensitivity to hyperoxia; (2) transdifferentiation of flbroblast as demonstrated by changes in ADRP expression is accompanied by metabolic enzymes changes affecting ribose acid synthesis from glucose, and (3) hyperoxia specifically inhibits lipogenesis from glucose. Hyperoxia-induced metabolic changes thus play a key role in the transdifferentiation of lung fibroblasts to myofibroblasts and the pathogenesis of BPD.
...
PMID:Oxygen-induced metabolic changes and transdifferentiation in immature fetal rat lung lipofibroblasts. 1240 71

LeCTR1 was initially isolated by both differential display reverse transcriptase-polymerase chain reaction screening for tomato (Lycopersicon esculentum) fruit ethylene-inducible genes and through homology with the Arabidopsis CTR1 cDNA. LeCTR1 shares strong nucleotide sequence homology with Arabidopsis CTR1, a gene acting downstream of the ethylene receptor and showing similarity to the Raf family of serine/threonine protein kinases. The length of the LeCTR1 transcribed region from ATG to stop codon (12,000 bp) is more than twice that of Arabidopsis CTR1 (4,700 bp). Structural analysis reveals perfect conservation of both the number and position of introns and exons in LeCTR1 and Arabidopsis CTR1. The introns in LeCTR1 are much longer, however. To address whether this structural conservation is indicative of functional conservation of the corresponding proteins, we expressed LeCTR1 in the Arabidopsis ctr1-1 (constitutive triple response 1) mutant under the direction of the 35S promoter. Our data clearly show that ectopic expression of LeCTR1 in the Arabidopsis ctr1-1 mutant can restore normal ethylene signaling. The recovery of normal ethylene sensitivity upon heterologous expression of LeCTR1 was also confirmed by restored glucose sensitivity absent in the Arabidopsis ctr1-1 mutant. Expression studies confirm ethylene responsiveness of LeCTR1 in various tissues, including ripening fruit, and may suggest the evolution of alternate regulatory mechanisms in tomato versus Arabidopsis.
...
PMID:LeCTR1, a tomato CTR1-like gene, demonstrates ethylene signaling ability in Arabidopsis and novel expression patterns in tomato. 1242 80

We describe a highly efficient two-step single-cell reverse transcriptase-polymerase chain reaction technique for analyzing gene expression at the single-cell level. Good reproducibility and a linear dose response indicated that the technique has high specificity and sensitivity for detection and quantification of rare RNA. Actin could be used as an internal standard. The expression of message for Rubisco small subunit (RbcS), chlorophyll a/b-binding protein (Cab), sucrose (Suc):fructan-6-fructosyl transferase (6-SFT), and Actin were measured in individual photosynthetic cells of the barley (Hordeum vulgare) leaf. Only Actin was found in the non-photosynthetic epidermal cells. Cab, RbcS, and 6-SFT genes were expressed at a low level in mesophyll and parenchymatous bundle sheath (BS) cells when sampled from plants held in dark for 40 h. Expression increased considerably after illumination. The amount of 6-SFT, Cab, and RbcS transcript increased more in mesophyll cells than in the parenchymatous BS cells. The difference may be caused by different chloroplast structure and posttranscriptional control in mesophyll and BS cells. When similar single-cell samples were assayed for Suc, glucose, and fructan, there was high correlation between 6-SFT gene expression and Suc and glucose concentrations. This is consistent with Suc concentration being the trigger for transcription. Together with earlier demonstrations that the mesophyll cells have a higher sugar threshold for fructan polymerization, our data may indicate separate control of transcription and enzyme activity. Values for the sugar concentrations of the individual cell types are reported.
...
PMID:Rubisco small subunit, chlorophyll a/b-binding protein and sucrose:fructan-6-fructosyl transferase gene expression and sugar status in single barley leaf cells in situ. Cell type specificity and induction by light. 1242 99

The alpha-galactosidase gene (aga) and a gene coding for a putative transcriptional regulator from the LacI/GalR family (galR) of Lactococcus raffinolactis ATCC 43920 were cloned and sequenced. When transferred into Lactococcus lactis and Pediococcus acidilactici strains, aga modified the sugar fermentation profile of the strains from melibiose negative (Mel(-)) to melibiose positive (Mel(+)). Analysis of galA mutants of L. lactis subsp. cremoris MG1363 indicated that the putative galactose permease GalA is also needed to obtain the Mel(+) phenotype. Consequently, GalA may also transport melibiose into this strain. We demonstrated that when aga was associated with the theta-type replicon of a natural L. lactis plasmid, it constituted the selectable marker of a cloning vector named pRAF800. Transcriptional analysis by reverse transcriptase PCR suggests that this vector is also suitable for gene expression. The alpha-galactosidase activity conferred by pRAF800 was monitored in an industrial strain grown in the presence of various carbon sources. The results indicated that the enzymatic activity was induced by galactose and melibiose, but not by glucose or lactose. The gene encoding the phage defense mechanism, AbiQ, was cloned into pRAF800, and the resulting clone (pRAF803) was transferred into an industrial L. lactis strain that became highly phage resistant. The measurements of various growth parameters indicated that cells were not affected by the presence of pRAF803. Moreover, the plasmid was highly stable in this strain even under starter production conditions. The L. raffinolactis aga gene represents the basis of a novel and convenient food-grade molecular tool for the genetic engineering of lactic acid bacteria.
...
PMID:Novel food-grade plasmid vector based on melibiose fermentation for the genetic engineering of Lactococcus lactis. 1245 Aug 40

Neurogenin3 is a member of the basic helix-loop-helix ('bHLH') family of transcription factors. It plays a crucial role in the commitment of embryonic endoderm into the pancreatic differentiation programme. This factor is considered to act upstream of a cascade of other transcription factors, leading to the fully differentiated endocrine phenotype. Direct observation of the sequential activation of these factors starting from Neurogenin3 had never been demonstrated. By using retinoic acid-derived-endoderm F9 cells as a model, the present study indicates that the ectopic expression of Neurogenin3 is able to start the differentiation pathway of endocrine pancreas. Neurogenin3 triggers the expression of several pancreatic transcription factors following a well defined temporal activation sequence. By reverse transcriptase PCR, immunohistochemistry and RIA, it is shown that stable transfected cells are able to form embryod bodies that produce insulin in response to glucose stimulation. This is the first report of a differentiation event induced by the ectopic expression of a transcription factor in embryonic pluripotent stem cells.
...
PMID:Neurogenin3 triggers beta-cell differentiation of retinoic acid-derived endoderm cells. 1252 76


<< Previous 1 2 3 4 5 6 7 8 9 10

---