Página 2 dos resultados de 259 itens digitais encontrados em 0.028 segundos

Identification of a cytochrome P450 gene by reverse transcription--PCR using degenerate primers containing inosine.

Shen, Z; Wells, R L; Liu, J; Elkind, M M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/12/1993 EN
Relevância na Pesquisa
25.68%
A cytochrome P450-like gene, tentatively named P450CMEF, was amplified by a mixed oligonucleotide-primed amplification of cDNA from C3H mouse embryo fibroblast cells, designated 10T1/2, that had been treated with 7,12-dimethylbenz[a]anthracene (DMBA) or benz[a]anthracene (BA). A set of inosine-containing degenerate primers that were targeted to two conserved regions of known cytochrome P450 cDNAs were used. One primer was coded for the well-described and conserved heme-binding region of P450 enzymes, and the second was designed based upon other considerations of homology among P450 molecules. One of the four PCR-amplified cDNA products hybridized to two major RNA bands, 4.2 and 5.3 kb, that were induced by DMBA or BA. The amino acid sequence of the fragment deduced from the base-sequence data indicate that the amplified cDNA has a 50-55% identity with the cytochrome P450 subfamily 1A. The induction of P450CMEF mRNA preceded the induction of aryl hydrocarbon hydroxylase activity after DMBA or BA treatment, suggesting that the product of P450CMEF is involved in the metabolism of these polycyclic aromatic hydrocarbons in 10T1/2 cells. From the partial sequence of the cDNA identified by this procedure, we propose that P450CMEF is a member of the P450 superfamily...

GerN, an Antiporter Homologue Important in Germination of Bacillus cereus Endospores

Thackray, Penny D.; Behravan, Javad; Southworth, Thomas W.; Moir, Anne
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /01/2001 EN
Relevância na Pesquisa
25.81%
A homologue of the grmA spore germination gene of Bacillus megaterium and of a NaH-antiporter gene (napA) of Enterococcus hirae has been identified in Bacillus cereus 569 (ATCC 10876). The putative protein product has 58 and 43% amino acid identity with GrmA and NapA, respectively. Insertional inactivation of this B. cereus gene, named gerN, did not affect vegetative growth or sporulation. The null mutant spores were 30-fold slower to germinate in inosine (5 mM) but germinated almost normally in response to l-alanine (10 mM). The null mutant spores germinated after several hours with inosine as the sole germinant, but germination was asynchronous and the normal order of germination events was perturbed. At a suboptimal germinant concentration (50 μM), inosine germination was completely blocked in the mutant, while the rate of germination in 50 μM l-alanine was reduced to one-third of that of the wild type. The requirement for GerN function in the response to a particular germinant suggests that a germination receptor may have a specifically associated antiporter, which is required at the initiation of germination and which, in the case of the inosine receptor, is GerN. Since germination in suboptimal concentrations of l-alanine shows a delay...

Synthesis and polymerase incorporation of 5′-amino-2′,5′-dideoxy-5′-N-triphosphate nucleotides

Wolfe, Jia Liu; Kawate, Tomohiko; Belenky, Alexei; Stanton, Vincent
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em 01/09/2002 EN
Relevância na Pesquisa
25.63%
Owing to the markedly increased reactivity of amino functional groups versus hydroxyls, the 5′-amino-5′-deoxy nucleoside and nucleotide analogs have proven widely useful in biological, pharmaceutical and genomic applications. However, synthetic procedures leading to these analogs have not been fully explored, which may possibly have limited the scope of their utility. Here we describe the synthesis of the 5′-amino-2′,5′-dideoxy analogs of adenosine, cytidine, guanosine, inosine and uridine from their respective naturally occurring nucleosides via the reduction of 5′-azido-2′,5′-dideoxy intermediates using the Staudinger reaction, and the high yield conversion of these modified nucleosides and 5′-amino-5′-deoxythymidine to the corresponding 5′-N-triphosphates through reaction with trisodium trimetaphosphate in the presence of tris(hydroxymethyl)aminomethane (Tris). We also show that each of these nucleotide analogs can be efficiently incorporated into DNA by the Klenow fragment of Escherichia coli DNA polymerase I when individually substituted for its naturally occurring counterpart. Mild acid treatment of the resulting DNA generates polynucleotide fragments that arise from specific cleavage at each modified nucleotide...

6-Diazo-5-Oxo-l-Norleucine Inhibition of Escherichia coli

Coggin, J. H.; Martin, W. R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1965 EN
Relevância na Pesquisa
25.74%
Coggin, J. H., Jr. (The University of Chicago, Chicago, Ill.), and W. R. Martin. 6-Diazo-5-oxo-l-norleucine inhibition of Escherichia coli. J. Bacteriol. 89:1348–1353. 1965.—The glutamine analogue 6-diazo-5-oxo-l-norleucine (DON) induced filaments and spheroplasts in Escherichia coli during the transition of sensitive populations to a state of resistance. Resistance developed at a frequency suggesting mutant selection. The morphology of cells resistant to 100 μg of DON per ml was indistinguishable from that of sensitive cells. DON-resistant cells exhibited an extended growth lag when cultured in the absence of the drug. This extended lag could be reduced to the lag time of parent sensitive cells by a combination of d-glucosamine and inosine or by DON. Viable counts during the lag period of resistant cells indicate that this lag results from a decrease in the number of cells during the first 2 hr of incubation. A combination of d-glucosamine and inosine was required for complete prevention of the DON inhibition of sensitive cells. The results indicate that DON not only inhibits de novo purine biosynthesis but that it also prevents hexosamine synthesis and, ultimately, cell-wall synthesis in E. coli.

Purine metabolite inosine is an adrenergic neurotrophic substance for cultured chicken sympathetic neurons.

Zurn, A D; Do, K Q
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1988 EN
Relevância na Pesquisa
25.85%
Purines are ubiquitous endogenous cellular metabolites that have been postulated as neurotransmitters or neuromodulators in the nervous system. Recently, we showed that a low-molecular-mass component present in liver-conditioned medium selectively enhances the adrenergic properties of dissociated chicken sympathetic neurons in culture. We report here that this substance is inosine, a purine metabolite. Indeed, analysis of the low-molecular-mass fraction of liver-conditioned medium by HPLC shows that the neurotrophic activity coelutes with and has the same absorption spectrum as inosine. Inosine increases incorporation of [3H]leucine into neuronal protein and stimulates catecholamine, but not acetylcholine, production by the sympathetic neurons in a dose-dependent fashion (half-maximal stimulation at 10(-6) M). This effect can be blocked by 5 x 10(-6) M dipyridamole, an inhibitor of nucleoside transport. Inosine therefore appears to be capable of modulating adrenergic phenotypic expression in cultured sympathetic neurons by acting via an as-yet-unknown intracellular pathway.

The conformational variability of an adenosine.inosine base-pair in a synthetic DNA dodecamer.

Leonard, G A; Booth, E D; Hunter, W N; Brown, T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 25/09/1992 EN
Relevância na Pesquisa
25.72%
A crystal structure analysis of the synthetic deoxydodecamer d(CGCAAATTIGCG) which contains two adenosine.inosine (A.I) mispairs has revealed that, in this sequence, the A.I base-pairs adopt a A(anti).I(syn) configuration. The refinement converged at R = 0.158 for 2004 reflections with F greater than or equal to 2 sigma(F) in the range 7.0-2.5A for a model consisting of the DNA duplex and 71 water molecules. A notable feature of the structure is the presence of an almost complete spine of hydration spanning the minor groove of the whole of the (AAATTI)2 core region of the duplex. pH-dependent ultraviolet melting studies have suggested that the base-pair observed in the crystal structure is, in fact, a protonated AH+ (anti).I(syn) species and that the A.I base-pairs in the sequence studied display the same conformational variability as A.G mispairs in the sequence d(CGCAAATTGGCG). The AH+(anti).I(syn) base-pair predominates below pH 6.5 and an A(anti).I(anti) mispair is the major species present between pH 6.5 and 8.0. The protonated base-pairs are held together by two hydrogen bonds one between N6(A) and O6(I) and the other between N1(A) and N7(I). This second hydrogen bond is a direct result of the protonation of the N1 of adenosine. The ultraviolet melting studies indicate that the A(anti).I(anti) base-pair is more stable than the A(anti).G(anti) base-pair but that the AH+(anti).I(syn) base pair is less stable than its AH+(anti).G(syn) analogue. Possible reasons for this observation are discussed.

A new synthesis of inosine from 5-amino-1-beta-D-ribofuranosyl-4-imidazole-carboxamide.

Okutsu, M; Yamazaki, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /01/1976 EN
Relevância na Pesquisa
25.8%
Inosine was prepared (15% yield) by treatment of 5-amino-1-beta-D-ribofuranosyl-4-imidazolecarboxamide (AICA-riboside) with chloroform in the presence of sodium methoxide. This ring closure can be reasonably explained by assuming the formation of dichlorocarbene from chloroform and alkali. Carbon tetrachloride or hexachloroethane as a carbene source was more effective for the ring closure of AICA-riboside, giving inosine in 48% and 51% yields respectively.

Mechanism of Action of 1-β-D-Ribofuranosyl-1,2,4-Triazole-3-Carboxamide (Virazole), A New Broad-Spectrum Antiviral Agent

Streeter, David G.; Witkowski, J. T.; Khare, Gyaneshwar P.; Sidwell, Robert W.; Bauer, Randy J.; Robins, Roland K.; Simon, Lionel N.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1973 EN
Relevância na Pesquisa
25.78%
The antiviral activity of the synthetic nucleoside, Virazole (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide), against measles virus in Vero cell cultures was substantially reversed by xanthosine, guanosine, and to a slightly lesser extent by inosine. Virazole 5′-phosphate was subsequently found to be a potent competitive inhibitor of inosine 5′-phosphate dehydrogenase (IMP:NAD+ oxidoreductase, EC 1.2.1.14) isolated from Escherichia coli (Km = 1.8 × 10-5 M) with a Ki of 2.7 × 10-7 M. Guanosine 5′-phosphate (GMP) was a competitive inhibitor of this enzyme with a Ki of 7.7 × 10-5 M. Virazole 5′-phosphate was similarly active against IMP dehydrogenase isolated from Ehrlich ascites tumor cells, with a Ki of 2.5 × 10-7 M. The Km for this enzyme was 1.8 × 10-5 M, and the Ki for GMP was 2.2 × 10-4 M. These results suggest that the antiviral activity of Virazole might be due to the inhibition of GMP biosynthesis in the infected cell at the step involving the conversion of IMP to xanthosine 5′-phosphate. This inhibition would consequently result in inhibition of the synthesis of vital viral nucleic acid.

Effect of adenosine and inosine on ureagenesis in hepatocytes.

Guinzberg, R; Laguna, I; Zentella, A; Guzman, R; Piña, E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/07/1987 EN
Relevância na Pesquisa
25.81%
Adenosine and inosine produced a dose-dependent stimulation of ureagenesis in isolated rat hepatocytes. Hypoxanthine, xanthine and uric acid were without effect. Half-maximally effective concentrations were 0.08 microM for adenosine and 5 microM for inosine. Activation of ureagenesis by both nucleosides had the following characteristics: (a) it was observed with either glutamine or (NH4)2CO3, provided that glucose was present; (b) it was not detected when glucose was replaced by lactate plus oleate; (c) it was mutually antagonized by glucagon, but not by adrenaline; and (d) it was dependent on Ca2+. We suggest that the action of adenosine and inosine on ureagenesis might be of physiological significance.

Intravenous infusion of adenosine but not inosine stimulates respiration in man.

Reid, P G; Watt, A H; Routledge, P A; Smith, A P
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1987 EN
Relevância na Pesquisa
25.85%
The effects on respiration of intravenous infusions of the endogenous nucleoside adenosine and its deaminated metabolite, inosine, administered in random order, single-blind, were compared in six healthy volunteers. The infusion rate of each nucleoside was initially 3.1 mg min-1 and was increased stepwise every 2 min, as tolerated, up to a possible maximum of 23.4 mg ml-1. The maximum dose rates received by all subjects were 8.5 mg min-1 for adenosine and 16.8 mg min-1 for inosine. Adenosine infusion at rates of 6.1 mg min-1 and above caused a significant increase in minute ventilation, principally due to an increase in tidal volume, with an associated significant fall in end-tidal Pco2. Mean inspiratory flow rate increased and expiratory duration decreased during adenosine infusion, but there was no change in inspiratory duration. Adenosine infusion also caused a significant increase in heart rate and a slight, but significant increase in systolic blood pressure. Infusion of inosine at dose rates up to 16.8 mg min-1 produced no pharmacological effects. This study shows that adenosine by infusion produces sustained respiratory stimulation in man and demonstrates that it does not depend on prior conversion of adenosine to inosine or related metabolites and that it is not secondary to systemic hypotension.

Extracellular 3′,5′-cAMP-Adenosine Pathway Inhibits Glomerular Mesangial Cell Growth

Dubey, Raghvendra K.; Rosselli, Marinella; Gillespie, Delbert G.; Mi, Zaichuan; Jackson, Edwin K.
Fonte: The American Society for Pharmacology and Experimental Therapeutics Publicador: The American Society for Pharmacology and Experimental Therapeutics
Tipo: Artigo de Revista Científica
Publicado em /06/2010 EN
Relevância na Pesquisa
25.8%
Abnormal growth of glomerular mesangial cells (GMCs) contributes to the pathophysiology of many types of nephropathy. Because adenosine is an autocrine/paracrine factor that potentially could regulate GMC proliferation and because the extracellular 3′,5′-cAMP-adenosine pathway (i.e., the conversion of extracellular 3′,5′-cAMP to 5′-AMP and adenosine on the cell surface) could generate adenosine in the biophase of GMC receptors, we investigated the role of the 3′,5′-cAMP-adenosine pathway in modulating growth [cell proliferation, DNA synthesis ([3H]thymidine incorporation), collagen synthesis ([3H]proline incorporation), and mitogen-activated protein kinase activity] of GMCs. The addition of exogenous 3′,5′-cAMP to human GMCs increased extracellular levels of 5′-AMP, adenosine, and inosine, and 3-isobutyl-1-methylxanthine (phosphodiesterase inhibitor), 1,3-dipropyl-8-p-sulfophenylxanthine (ecto-phosphodiesterase inhibitor), and α,β-methylene-adenosine-5′-diphosphate (ecto-5′-nucleotidase inhibitor) attenuated the increases in adenosine and inosine. Forskolin augmented extracellular 3′,5′-cAMP and adenosine concentrations, and 2′,5′-dideoxyadenosine (adenylyl cyclase inhibitor) blocked these increases. Exogenous 3′...

Redirection of Silencing Targets by Adenosine-to-Inosine Editing of miRNAs

Kawahara, Yukio; Zinshteyn, Boris; Sethupathy, Praveen; Iizasa, Hisashi; Hatzigeorgiou, Artemis G.; Nishikura, Kazuko
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 23/02/2007 EN
Relevância na Pesquisa
25.76%
Primary transcripts of certain microRNA (miRNA) genes are subject to RNA editing that converts adenosine to inosine. However, the importance of miRNA editing remains largely undetermined. Here we report that tissue-specific adenosine-to-inosine editing of miR-376 cluster transcripts leads to predominant expression of edited miR-376 isoform RNAs. One highly edited site is positioned in the middle of the 5′-proximal half “seed” region critical for the hybridization of miRNAs to targets. We provide evidence that the edited miR-376 RNA silences specifically a different set of genes. Repression of phosphoribosyl pyrophosphate synthetase 1, a target of the edited miR-376 RNA and an enzyme involved in the uric-acid synthesis pathway, contributes to tight and tissue-specific regulation of uric-acid levels, revealing a previously unknown role for RNA editing in miRNA-mediated gene silencing.

Cardiac endothelial transport and metabolism of adenosine and inosine

Schwartz, Lisa M.; Bukowski, Thomas R.; Revkin, James H.; Bassingthwaighte, James B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/1999 EN
Relevância na Pesquisa
25.68%
The influence of transmembrane flux limitations on cellular metabolism of purine nucleosides was assessed in whole organ studies. Transcapillary transport of the purine nucleosides adenosine (Ado) and inosine (Ino) via paracellular diffusion through interendothelial clefts in parallel with carrier-mediated transendothelial fluxes was studied in isolated, Krebs-Henseleit-perfused rabbit and guinea pig hearts. After injection into coronary inflow, multiple-indicator dilution curves were obtained from coronary outflow for 90 s for 131I-labeled albumin (intravascular reference tracer), [3H]arabinofuranosyl hypoxanthine (AraH; extracellular reference tracer and nonreactive adenosine analog), and either [14C]Ado or [14C]Ino. Ado or Ino was separated from their degradative products, hypoxanthine, xanthine, and uric acid, in each outflow sample by HPLC and radioisotope counting. Ado and Ino, but not AraH, permeate the luminal membrane of endothelial cells via a saturable transporter with permeability-surface area product PSecl and also diffuse passively through interendothelial clefts with the same conductance (PSg) as AraH. These parallel conductances were estimated via fitting with an axially distributed, multi-pathway, four-region blood-tissue exchange model. PSg for AraH were ~4 and 2.5 ml · g−1 · min−1 in rabbits and guinea pigs...

The Impact of Inosine Triphosphatase Variants on Hemoglobin Level and Sustained Virologic Response of Chronic Hepatitis C in Korean

Kim, Ju Seung; Ahn, Sung-Min; Jung, Young Kul; Kwon, Oh Sang; Kim, Yun Soo; Choi, Duck Joo; Kim, Ju Hyun
Fonte: The Korean Academy of Medical Sciences Publicador: The Korean Academy of Medical Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
25.68%
Two variants of the inosine triphosphatase (ITPA: rs1127354, rs7270101) gene cause ITPA deficiency and protect against the hemolytic toxicity of ribavirin. We investigated the clinical significance of ITPA variants in Korean patients treated with pegylated interferon (PEG-IFN) plus ribavirin. Of the 133 patients, 108 were CC and 25 were non-CC at rs1127354 (groups A and B, respectively). On the other hand, at rs7270101 all 133 were AA. The mean values of Hemoglobin (Hgb) after 4, 8, and 12 weeks of treatment in groups A and B were 12.2 and 14.0, 11.8 and 13.2, and 11.5 and 12.9, respectively (P=0.001, 0.036, 0.036). Sustained virologic response (SVR) was achieved in 67.8% (40/59) of genotype 1 patients and in 75% (27/36) of non-genotype 1 patients. Regarding ITPA variants, SVR was achieved by 66% and 80% of genotype 1 (P=0.282), and by 78% and 71% (P=0.726) of non-genotype 1. SVR was not significantly different in groups A and B. In conclusion, non-CC at rs1127354 without involvement of rs7270101 is strongly associated with protection from ribavirin-induced anemia, however, ITPA genotype is not associated with SVR.

Structural Determinants of the 5′-Methylthioinosine Specificity of Plasmodium Purine Nucleoside Phosphorylase

Donaldson, Teraya M.; Ting, Li-Min; Zhan, Chenyang; Shi, Wuxian; Zheng, Renjian; Almo, Steven C.; Kim, Kami
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 08/01/2014 EN
Relevância na Pesquisa
25.77%
Plasmodium parasites rely upon purine salvage for survival. Plasmodium purine nucleoside phosphorylase is part of the streamlined Plasmodium purine salvage pathway that leads to the phosphorylysis of both purines and 5′-methylthiopurines, byproducts of polyamine synthesis. We have explored structural features in Plasmodium falciparum purine nucleoside phosphorylase (PfPNP) that affect efficiency of catalysis as well as those that make it suitable for dual specificity. We used site directed mutagenesis to identify residues critical for PfPNP catalytic activity as well as critical residues within a hydrophobic pocket required for accommodation of the 5′-methylthio group. Kinetic analysis data shows that several mutants had disrupted binding of the 5′-methylthio group while retaining activity for inosine. A triple PfPNP mutant that mimics Toxoplasma gondii PNP had significant loss of 5′-methylthio activity with retention of inosine activity. Crystallographic investigation of the triple mutant PfPNP with Tyr160Phe, Val66Ile, andVal73Ile in complex with the transition state inhibitor immucillin H reveals fewer hydrogen bond interactions for the inhibitor in the hydrophobic pocket.

A Unique Primer with an Inosine Chain at the 5′-Terminus Improves the Reliability of SNP Analysis Using the PCR-Amplified Product Length Polymorphism Method

Shojo, Hideki; Tanaka, Mayumi; Takahashi, Ryohei; Kakuda, Tsuneo; Adachi, Noboru
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 18/09/2015 EN
Relevância na Pesquisa
25.74%
Polymerase chain reaction-amplified product length polymorphism (PCR-APLP) is one of the most convenient and reliable methods for single nucleotide polymorphism (SNP) analysis. This method is based on PCR, but uses allele-specific primers containing SNP sites at the 3′-terminus of each primer. To use this method at least two allele-specific primers and one “counter-primer”, which serves as a common forward or reverse primer of the allele-specific primers, are required. The allele-specific primers have SNP sites at the 3′-terminus, and another primer should have a few non-complementary flaps at the 5′-terminus to detect SNPs by determining the difference of amplicon length by PCR and subsequent electrophoresis. A major disadvantage of the addition of a non-complementary flap is the non-specific annealing of the primer with non-complementary flaps. However, a design principle for avoiding this undesired annealing has not been fully established, therefore, it is often difficult to design effective APLP primers. Here, we report allele-specific primers with an inosine chain at the 5′-terminus for PCR-APLP analysis. This unique design improves the competitiveness of allele-specific primers and the reliability of SNP analysis when using the PCR-APLP method.

Feeding behavior in juvenile snook, Centropomus undecimalis. I. Individual effect of some chemical substances

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
EN
Relevância na Pesquisa
25.68%
This study was designed to analyze the influence of certain chemical substances on the feeding behavior of juvenile common snook. The following chemicals were tested: L-alanine, L-leucine, L-isoleucine, L-glutamic acid, glycine, L-proline, L-histidine, L-serine, L-lysine, L-arginine, inosine-5-triphosphate, and uridine. Feeding responses were studied in tanks containing one or two fish. The substances were placed in pellets made of agar, at a concentration of 0.01 M. The chemicals found to act as attractants were: uridine, L-isoleucine, and inosine with one fish; and those plus glycine, L-proline, L-arginine, L-leucine, and L-glutamic acid with two fish. The feeding responses were stronger with two fish, indicating that the number of fish had an influence on feeding behavior.

Inverted Alu dsRNA structures do not affect localization but can alter translation efficiency of human mRNAs independent of RNA editing

Capshew, C.R.; Dusenbury, K.L.; Hundley, H.A.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
25.76%
With over one million copies, Alu elements are the most abundant repetitive elements in the human genome. When transcribed, interaction between two Alus that are in opposite orientation gives rise to double-stranded RNA (dsRNA). Although the presence of dsRNA in the cell was previously thought to only occur during viral infection, it is now known that cells express many endogenous small dsRNAs, such as short interfering RNA (siRNAs) and microRNA (miRNAs), which regulate gene expression. It is possible that long dsRNA structures formed from Alu elements influence gene expression. Here, we report that human mRNAs containing inverted Alu elements are present in the mammalian cytoplasm. The presence of these long intramolecular dsRNA structures within 3′-UTRs decreases translational efficiency, and although the structures undergo extensive editing in vivo, the effects on translation are independent of the presence of inosine. As inverted Alus are predicted to reside in >5 of human protein-coding genes, these intramolecular dsRNA structures are important regulators of gene expression.

High-Throughput Multiplexed Transcript Analysis Yields Enhanced Resolution of 5-Hydroxytryptamine2C Receptor mRNA Editing ProfilesS⃞

Morabito, Michael V.; Ulbricht, Randi J.; O'Neil, Richard T.; Airey, David C.; Lu, Pengcheng; Zhang, Bing; Wang, Lily; Emeson, Ronald B.
Fonte: The American Society for Pharmacology and Experimental Therapeutics Publicador: The American Society for Pharmacology and Experimental Therapeutics
Tipo: Artigo de Revista Científica
Publicado em /06/2010 EN
Relevância na Pesquisa
25.72%
RNA editing is a post-transcriptional modification in which adenosine residues are converted to inosine (adenosine-to-inosine editing). Commonly used methodologies to quantify RNA editing levels involve either direct sequencing or pyrosequencing of individual cDNA clones. The limitations of these methods lead to a small number of clones characterized in comparison to the number of mRNA molecules in the original sample, thereby producing significant sampling errors and potentially erroneous conclusions. We have developed an improved method for quantifying RNA editing patterns that increases sequence analysis to an average of more than 800,000 individual cDNAs per sample, substantially increasing accuracy and sensitivity. Our method is based on the serotonin 2C receptor (5-hydroxytryptamine2C; 5HT2C) transcript, an RNA editing substrate in which up to five adenosines are modified. Using a high-throughput multiplexed transcript analysis, we were able to quantify accurately the expression of twenty 5HT2C isoforms, each representing at least 0.25% of the total 5HT2C transcripts. Furthermore...

C2´, 3´- Cyclic carbonates derived from uridine and inosine

Spegazzini,N.; Capello,M.; Iglesias,L.E.; Iribarren,A.M.
Fonte: Anales de la Asociación Química Argentina Publicador: Anales de la Asociación Química Argentina
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 EN
Relevância na Pesquisa
25.74%
New compounds 5'-O-(4, 4'-dimethoxytrityl)uridine-2', 3'-carbonate and 5'-O-(4, 4'-dimethoxytrityl)inosine-2', 3'-carbonate were obtained in 65 % and 43 % yield, respectively, through the reaction of the corresponding 5'-O-(4, 4'-dimethoxytrityl) nucleosides with 1, 1'-carbonyldiimidazole in dioxane at 20º C.