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At least 919 records · Page 51Linked to original sources
PubMed1979

Mapping of RNA by a modification of the Berk-Sharp procedure: the 5' termini of 15 S beta-globin mRNA precursor and mature 10 s beta-globin mRNA have identical map coordinates.

We have used a modification of the Berk-Sharp technique to determine that the 5' termini of the mouse 15 S beta-globin precursor and the mature mRNA have identical map coordinates. The modification involves the use of 5' (or 3') terminally labeled probes; it allows the detection of the precursor in the presence of excess mature mRNA.

Animals↗
PubMed1980

Sequences hybridizing to mRNA, oligo(dT) and dsRNA from pre-mRNA are contiguous in the cloned mouse DNA fragments.

Fragments from the DNA of mouse embryos produced by restriction endonucleases HindIII were cloned in pBR322 plasmid and examined for the ability to hybridize in situ with [32P] labeled cDNA synthesized from the polysomal poly(A)+mRNA template. Several of the selected clones were examined for the presence of specific sequences inside the cloned mouse DNA fragments by the blotting procedure of southern [1]. The data obtained indicate that the majority of the cloned mouse DNA fragments contained sequences hybridizing with cDNA, oligo(dT) and double-stranded regions from pre-mRNA. The results of hybridization experiments and double digestion with HindIII+HaeIII endonucleases provide evidence that these sequences could be contiguous in the given restriction DNA fragments.

Animals↗
PubMed1993

The induction of LTP increases BDNF and NGF mRNA but decreases NT-3 mRNA in the dentate gyrus.

We have investigated the expression of the mRNAs for brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4) in the hippocampus before and after induction of long term potentiation (LTP) of synaptic transmission in the dentate gyrus through stimulation of the perforant path (PP). A unilateral PP stimulation produced a bilateral increase in the mRNA for both BDNF and NGF in granular neurones of the dentate gyrus but not in other neurones in the hippocampus. The mRNA for neurotrophin-3 (NT-3) was bilaterally decreased by LTP but that of NT-4 remained at the basal level. These results suggest that individual neurotrophic factors may play different roles in neuronal plasticity.

Animals↗
PubMed1997

A novel translational repressor mRNA is edited extensively in livers containing tumors caused by the transgene expression of the apoB mRNA-editing enzyme.

Transgene expression of the apolipoprotein B mRNA-editing enzyme (APOBEC-1) causes dysplasia and carcinoma in mouse and rabbit livers. Using a modified differential display technique, we identified a novel mRNA (NAT1 for novel APOBEC-1 target no. 1) that is extensively edited at multiple sites in these livers. The aberrant editing alters encoded amino acids, creates stop codons, and results in markedly reduced levels of the NAT1 protein in transgenic mouse livers. NAT1 is expressed ubiquitously and is extraordinarily conserved among species. It has homology to the carboxy-terminal portion of the eukaryotic translation initiation factor (eIF) 4G that binds eIF4A and eIF4E to form eIF4F. NAT1 binds eIF4A but not eIF4E and inhibits both cap-dependent and cap-independent translation. NAT1 is likely to be a fundamental translational repressor, and its aberrant editing could contribute to the potent oncogenesis induced by overexpression of APOBEC-1.

APOBEC-1 Deaminase↗
PubMed2006

STABILIZED1, a stress-upregulated nuclear protein, is required for pre-mRNA splicing, mRNA turnover, and stress tolerance in Arabidopsis.

In plants, many gene transcripts are very unstable, which is important for the tight control of their temporal and spatial expression patterns. To identify cellular factors controlling the stability of unstable mRNAs in plants, we used luciferase imaging in Arabidopsis thaliana to isolate a recessive mutant, stabilized1-1 (sta1-1), with enhanced stability of the normally unstable luciferase transcript. The sta1-1 mutation also causes the stabilization of some endogenous gene transcripts and has a range of developmental and stress response phenotypes. STA1 encodes a nuclear protein similar to the human U5 small ribonucleoprotein-associated 102-kD protein and to the yeast pre-mRNA splicing factors Prp1p and Prp6p. STA1 expression is upregulated by cold stress, and the sta1-1 mutant is defective in the splicing of the cold-induced COR15A gene. Our results show that STA1 is a pre-mRNA splicing factor required not only for splicing but also for the turnover of unstable transcripts and that it has an important role in plant responses to abiotic stresses.

Arabidopsis↗
PubMed2004

A multi-protein complex containing cold shock domain (Y-box) and polypyrimidine tract binding proteins forms on the vascular endothelial growth factor mRNA. Potential role in mRNA stabilization.

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis and post-transcriptional regulation plays a major role in VEGF expression. Both the 5'- and 3'-UTR are required for VEGF post-transcriptional regulation but factors binding to functional sequences within the 5'-UTR have not been fully characterized. We report here the identification of complexes, binding to the VEGFmRNA 5'- and 3'-UTR, that contain cold shock domain (CSD) and polypyrimidine tract binding (PTB) RNA binding proteins. Analysis of the CSD/PTB binding sites revealed a potential role in VEGF mRNA stability, in both noninduced and induced conditions, demonstrating a general stabilizing function. Such a stabilizing mechanism had not been reported previously for the VEGF gene. We further found that the CSD/PTB-containing complexes are large multiprotein complexes that are most likely preformed in solution and we demonstrate that PTB is associated with the VEGF mRNA in vivo. Complex formation between CSD proteins and PTB has not been reported previously. Analysis of the CSD/PTB RNA binding sites revealed a novel CSD protein RNA recognition site and also demonstrated that CSD proteins may direct the binding of CSD/PTB complexes. We found the same complexes binding to an RNA-stabilizing element of another growth factor gene, suggesting a broader functional role for the CSD/PTB complexes. Finally, as the VEGF gene is also regulated at the transcriptional level by CSD proteins, we propose a combined transcriptional/post-transcriptional role for these proteins in VEGF and other growth factor gene regulation.

3' Untranslated Regions↗
PubMed1977

Synthesis of mRNA guanylyltransferase and mRNA methyltransferases in cells infected with vaccinia virus.

Guanylyltransferase and methyltransferases that modify the 5'-terminals of viral mRNA's to form the structures m7G(5')pppAm- and m7G(5')pppGm- appear to be synthesized afte- vaccinia virus infection of HeLa cells. Elevations in these enzyme activities were detected within 1 h after virus inoculation and increased 15- to 30-fold by 4 to 10 h. Increases in the guanylyl- and methyltransferase activities were prevented by cycloheximide, an inhibitor of protein synthesis, but not by cytosine arabinoside, an inhibitor of DNA synthesis. The latter results suggest that the mRNA guanylyl- and methyltransferases are "early" or prereplicative viral gene products. The guanylyltransferase and two methyltransferases, a guanine-7-methyltransferase and nucleoside-2'-methyltransferase, were isolated by column chromatography from infected cell extracts and found to have properties similar or identical to those of the corresponding enzyme previously isolated from vaccinia virus cores. In contrast, enzymes with these properties could not be isolated from uninfected cells.

Cycloheximide↗
PubMed1977

Early gene expression of adenovirus type 2: R-loop mapping of mRNA and time course of viral DNA, mRNA, and protein synthesis.

Adenovirus type 2 DNA was hybridized to early mRNA isolated from the cytoplasm of infected cells prior to the initiation of viral DNA synthesis. Resulting R loops were visualized in the electron microscope, and their positions were oriented with the help of DNA fragments generated by digestion with the restriction endonuclease BamHI. Early RNA was found to map (in order of relative R-loop frequency) with midpoints near positions 0.95, 0.80, 0.03, 0.65, and 0.09 on the conventional adenovirus map. The time of appearance of individual viral mRNA's was compared to the time course of viral protein and DNA synthesis. We present a refined map of adenovirus gene functions which is based on results documented in this and the accompanying study by Meyer et al. (1977), as well as on data published by other laboratories.

Adenoviruses, Human↗
PubMed1979

Genome complexities of the three mRNA species of snowshoe hare bunyavirus and in vitro translation of S mRNA to viral N polypeptide.

The genome complexities of the principal intracellular viral complementary RNA species of the snowshoe hare bunyavirus have been analyzed by duplex analyses involving hybridization of complementary RNA to individual 32P-labeled viral RNA species (large, L; medium, M; and small, S), recovery of nuclease-resistant duplexes, and determination of the oligonucleotide fingerprints of the protected 32P-labeled viral sequences. The result for the M RNA (which codes for the glycoproteins G1 and G2; J. R. Gentsch and D. H. L. Bishop, J. Virol. 30:767-770, 1979) indicates that there is a single polycistronic M mRNA. Similar results were obtained for the L and S RNA species. In vitro translation studies with the S complementary RNA species of snowshoe hare virus as well as melted purified S duplexes substantiate earlier genetic and molecular studies (J. R. Gentsch and D. H. L. Bishop, J. Virol. 28:417-419, 1978; J. Gentsch, D. H. L. Bishop, and J. F. Obijeski, J. Gen. Virol. 34-257-268, 1977), which indicate that S mRNA codes for the virion nucleocapsid protein N.

Animals↗
PubMed1994

Novel features of the respiratory tract T-cell response to influenza virus infection: lung T cells increase expression of gamma interferon mRNA in vivo and maintain high levels of mRNA expression for interleukin-5 (IL-5) and IL-10.

Analysis of the respiratory tract before and after primary influenza virus infection revealed a virus-induced preferential accumulation of a CD8+ T-cell population that coexpresses mRNA for interleukin-5 (IL-5) and IL-10 with virus dose-dependent high levels of gamma interferon. However, cytokine production in lung tissues was not restricted to the T-cell population, since CD3- cells were found to express mRNA for various cytokines, including IL-4 and particularly IL-6 and granulocyte-macrophage colony-stimulating factor. These data provide in vivo evidence for a local respiratory tract immune response to influenza virus infection dominated by cytokine-producing CD8+ T cells.

Animals↗
PubMed1997

Modulation of the fate of cytoplasmic mRNA by AU-rich elements: key sequence features controlling mRNA deadenylation and decay.

Regulation of cytoplasmic deadenylation has a direct impact on the fate of mRNA and, consequently, its expression in the cytoplasm. AU-rich elements (AREs) found in the 3' untranslated regions of many labile mRNAs are the most common RNA-destabilizing elements known in mammalian cells. AREs direct accelerated deadenylation as the first step in mRNA turnover. Recently we have proposed that AREs can be divided into three different classes. mRNAs bearing either the class I AUUUA-containing ARE or the class III non-AUUUA ARE display synchronous poly(A) shortening, whereas class II ARE-containing mRNAs are deadenylated asynchronously, with the formation of poly(A)- intermediates. In this study, we have systematically characterized the deadenylation kinetics displayed by various AREs and their mutant derivatives. We find that a cluster of five or six copies of AUUUA motifs in close proximity forming various degrees of reiteration is the key feature that dictates the choice between processive versus distributive deadenylation. An AU-rich region 20 to 30 nucleotides long immediately 5' to this cluster of AUUUA motifs can greatly enhance the destabilizing ability of the AUUUA cluster and is, therefore, an integral part of the class I and class II AREs. These two features are the defining characteristics of class II AREs. Our results are consistent with the interpretation that the pentanucleotide AUUUA, rather than the nonamer UUAUUUA(U/A)(U/A), is both an essential and the minimal sequence motif of AREs. Our study provides the groundwork for future characterization of ARE-binding proteins identified by in vitro gel shift assays in order to stringently define their potential role in the ARE-mediated decay pathway. Moreover, transformation of deadenylation kinetics from one type to the other by mutations of AREs implies the existence of cross talk between the ARE and 3' poly(A) tail, which dictates the decay kinetics.

3T3 Cells↗
PubMed1976

Translation of ovalbumin mRNA in Xenopus laevis oocytes. Characterization of the system and effects of estrogen on injected mRNA populations.

Ovalbumin messenger RNA (mRNAov) purified from hen oviduct was injected into Xenopus laevis oocytes. The oocytes were incubated in culture medium containing [3H]leucine. Analysis of the oocyte cytosol on Sephadex G-15O columns demonstrated a peak of radioactivity which cochromatographed with authentic ovalbumin. Radioactive protein contained in this peak was precipitated by ovalbumin antiserum, coelectrophoresed with ovalbumin on sodium dodecyl sulfate (SDS) and urea gels at pH 8.7, and eluted with the protein at the same pH (4.8) on CM-cellulose chromatography. Injection of increasing amounts of mRNAov was found to elicit a linear response in terms of ovalbumin synthesis. Moreover, there was linear incorporation of radioactivity into microinjected oocytes over a minimum period of 91 h. Less than 1 ng mRNAov was detected in this system. Ovalbumin mRNA activity was present in RNA preparations from chicks treated with estrogen but was undetectable in animals withdrawn from the hormone. This study constitutes an initial demonstration of a steroid hormone-induced alteration in mRNA population as assayed in intact viable heterologous cells.

Animals↗
PubMed1993

Benign prostatic hyperplasia and normal prostate aging: differences in types I and II 5 alpha-reductase and steroid hormone receptor messenger ribonucleic acid (mRNA) levels, but not in insulin-like growth factor mRNA levels.

Benign prostatic hyperplasia (BPH) is so common in elderly men that the development of adenomatous nodules in this organ can be seen as a normal age-dependent process. In this work, we used Northern blotting to compare the levels of androgen, estrogen, and insulin-like growth factor-I (IGF-I) receptor in young (age range, 23-33; n = 3), old normal (age range, 52-80; n = 3), and BPH-affected subjects (age range, 66-87; n = 15). We have also investigated in these groups the expression of genes coding for the two 5 alpha-reductases (types I and II), aromatase, IGF-I, and IGF-II. Our results show significantly increased levels of IGF mRNA in old healthy and BPH-affected subjects; the respective rises for IGF-I, IGF-II, and IGF-I receptor mRNAs were 3.0-, 2.9-, and 1.5-fold (BPH) and 2.7-, 2.4-, and 1.8-fold (old normal controls). For estrogen receptor, androgen receptor, and type I and II 5 alpha-reductase mRNAs, a marked but opposite effect was observed in adenomatous tissues only; the respective levels were 2.2-, 1.8-, 3.9-, and 1.7-fold lower than those in young adult subjects, whereas no significant differences were recorded between the two normal groups. Morphometric analysis of each tissue specimen confirmed the significantly lower epithelium/stroma ratio in adenomas compared to young or old healthy tissues. Together, these observations suggest that prostatic adenomas may result from at least two conjugate processes: one characterized by a drop in the mRNA levels of steroid hormone receptors, which might be associated with a lower epithelium/stroma ratio, and another characterized by normal aging phenomena, of which the increased production of IGFs and IGF-I receptor transcripts could be biochemical markers.

Adult↗
PubMed2005

Nonsense-mediated mRNA decay factors act in concert to regulate common mRNA targets.

Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that degrades mRNAs containing nonsense codons, and regulates the expression of naturally occurring transcripts. While NMD is not essential in yeast or nematodes, UPF1, a key NMD effector, is essential in mice. Here we show that NMD components are required for cell proliferation in Drosophila. This raises the question of whether NMD effectors diverged functionally during evolution. To address this question, we examined expression profiles in Drosophila cells depleted of all known metazoan NMD components. We show that UPF1, UPF2, UPF3, SMG1, SMG5, and SMG6 regulate in concert the expression of a cohort of genes with functions in a wide range of cellular activities, including cell cycle progression. Only a few transcripts were regulated exclusively by individual factors, suggesting that these proteins act mainly in the NMD pathway and their role in mRNA decay has not diverged substantially. Finally, the vast majority of NMD targets in Drosophila are not orthologs of targets previously identified in yeast or human cells. Thus phenotypic differences observed across species following inhibition of NMD can be largely attributed to changes in the repertoire of regulated genes.

Animals↗
PubMed2004

Glucose-stimulated somatostatin gene expression in the Brockmann bodies of rainbow trout (Oncorhynchus mykiss) results from increased mRNA transcription and not from altered mRNA stability.

Previously, we showed that glucose increases the steady-state levels of the mRNAs encoding two distinct preprosomatostatins (each containing [Tyr7, Gly10]-somatostatin-14 at their C-termini; denoted PPSS II' and PPSS II") in the endocrine pancreas (Brockmann body) of rainbow trout (Oncorhynchus mykiss). In the present study, isolated islet cells were used to determine whether glucose-stimulated expression resulted from altered rates of transcription and/or from changes in RNA stability. Nuclear run-on assays indicated that the number of PPSS II nascent transcripts were significantly higher in nuclei isolated from islet cells cultured in 10 mM glucose compared to those isolated from cells incubated in 4 mM glucose. High glucose (10 mM) did not, however, affect the stability of PPSS II mRNAs. These results indicate that glucose-stimulated somatostatin expression in the Brockmann bodies of rainbow trout results from increased endogenous mRNA transcription and not from altered mRNA stability.

Animals↗
PubMedDate not supplied

Differential effects in vivo of thyroid hormone on the expression of surfactant phospholipid, surfactant protein mRNA and antioxidant enzyme mRNA in fetal rat lung.

Antenatal administration of triiodo-L-thyronine (T3) to late gestation rats resulted in decreased lung antioxidant enzyme (AOE) activity but increased surfactant phospholipids. In fetal rat lung explant cultures, T3 decreased the expression of surfactant proteins (SP) A and B. There have been no reported studies of the simultaneous in vivo developmental influence of T3 on both pulmonary AOE and SP gene expression. We hypothesized that antenatal T3 treatment would cause differential regulation of surfactant phospholipid, SP, and AOE genes in the late gestation fetal rat. Timed pregnant rats received intramuscular injections of either T3 (7 mg/kg) or placebo on days 19 and 20 of gestation and fetuses were delivered on day 21. Fetal lung SP-A, SP-B, SP-C, and AOE mRNA levels were studied by Northern analysis. AOE mRNA levels were further quantitated by solution hybridization. Total lung phospholipids (TPL) and disaturated phosphatidylcholine (DSPC) content were quantitated by a phosphorus assay. T3 significantly increased TPL and DSPC content, and significantly decreased the expression of SP-A, SP-C, CuZnSOD, and catalase genes. Because of a crucial interplay of these factors for normal lung function at the time of birth, the molecular mechanisms by which these apparently opposing changes are accomplished warrant further investigation.

Animals↗
PubMed1993

D2-dopaminergic agonist quinpirole and 8-bromo-cAMP have opposite effects on Go alpha GTP-binding protein mRNA without changing D2 dopamine receptor mRNA levels in striatal neurones in primary culture.

Long-term coordinated regulations (during development or by agonists and second messenger molecules) of the expression of mRNAs encoding D2-dopamine (DA) receptors and D2 receptor-linked Go alpha proteins have been studied by Northern blot analysis in mouse embryonic striatal neurones in primary culture. During the course of the cell culture, the levels of both mRNAs increased, in conjunction with the maturation of the neurones. When the preparation was treated with the D2-DA agonist quinpirole (5-15 hrs, 10(-4) M), which decreases cAMP in these neurones, the levels of Go alpha mRNAs were enhanced whereas that of the D2 mRNA remained unchanged. Conversely, the Go alpha mRNAs, but not the D2 mRNA, decreased when the neurones were exposed to 8-bromo-cAMP (16 hrs, 10(-6) M). It is concluded that, in these experimental conditions where neurones have not yet established their connexions, the longterm regulation of the membrane transmission of D2-DA signal might implicate mainly the Go alpha encoding gene.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2005

Correlative studies on bFGF mRNA and MMP-9 mRNA expressions with microvascular density, progression, and prognosis of gastric carcinomas.

AIM: To investigate the mRNA expressions of bFGF and MMP-9 in gastric carcinomas so as to reveal their correlations with tumor microvascular density (MVD), invasion, metastasis, and prognosis. METHODS: In situ hybridization and immunohistochemical techniques were used to detect the expressions of bFGFmRNA and MMP-9mRNA and the proteins of CD34 in 105 specimens of gastric carcinomas. RESULTS: In situ hybridization study showed that positive rates of bFGF mRNA and MMP-9mRNA expressions were 60.95% and 59.19%; the mean MVD was 46.09+/-11.52 and 43.75+/-13.41, respectively in piece/0.72 mm(2) in tumors with bFGFmRNA and MMP-9mRNA positive expressions, which were significantly higher than those with negative expression (29.41+/-12.47; 33.45+/-13.92 piece/0.72 mm(2), respectively). The positive expression rates of bFGFmRNA and MMP-9mRNA were correlated to the tumor invasion depth (r(s) = 0.211, P = 0.031; r(s) = 0.335, P = 0.001), growing pattern (r(s) = 0.324, P = 0.001; r(s) = 0.267, P = 0.006), vessel invasion (r(s) = 0.579, P = 0.001; r(s) = 0.209, P = 0.032), lymph node metastasis (r(s) = 0.405, P = 0.001; r(s) = 0.343, P = 0.001) and distant metastasis (r(s) = 0.474, P = 0.001; r(s) = 0.468, P = 0.001), but not correlated to tumor type (r(s) = 0.134, P = 0.173; r(s) = 0.103, P = 0.145) and differentiations (r(s) = 0.096, P = 0.332; r(s) = 0.102, P = 0.298). The mean MVD was much higher in the tumors with infiltrating growth at stage T(3)-T(4), with vessel invasion, lymph node metastasis and distant metastasis than those with expanding growth type (t = 10.105, P = 0.001) at stage T(1)-T(2) (t = 5.961, P = 0.001), with non-vessel invasion (t = 7.394, P = 0.001), non-lymph node metastasis (t = 3.819, P = 0.01) and non-distant metastasis (t = 10.578, P = 0.001). Positive correlation was observed between MVD and the expressions of bFGFmRNA and MMP-9mRNA (t = 3.207, P = 0.002; t = 7.035, P = 0.001, respectively). The mean survival time and 5-year survival rate were lower in cases with MVD over 39.5 and the positive expressions of bFGFmRNA and MMP-9mRNA than those with MVD less than 39.5 and the negative expressions of bFGFmRNA and MMP-9mRNA. CONCLUSION: bFGF and MMP-9 promote the angiogenesis of the gastric cancers. Detection of the expressions of bFGF and MMP-9 can serve as a useful index to determine the angiogenesis, invasion, metastasis, and prognosis of gastric cancers.

Adult↗