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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Among the prokaryotae, the nucleotide ppGpp is a second messenger of physiological stress and starvation. The target of ppGpp is RNA polymerase, where it putatively binds and alters the enzyme's activity. Previous data had implicated the beta-subunit of Escherichia coli RNA polymerase as containing a single ppGpp binding site. In this study, a photocross-linkable derivative of ppGpp, 6-thioguanosine-3',5'-(bis)pyrophosphate (6-thio-ppGpp), was used to localize the ppGpp binding site. In in vitro transcription assays, 6-thio-ppGpp inhibited transcription from the argT promoter identically to bona fide ppGpp. The thio group of 6-thio-ppGpp is directly photoactivatable and is thus a zero-length cross-linker. Cross-linking of RNA polymerase was directed primarily to the beta'-subunit and could be competed efficiently by native ppGpp but not by GTP or GDP. Cyanogen bromide digestion analysis of the cross-linked beta'-subunit was consistent with an extreme N-terminal cross-link. To assess allosteric consequences of ppGpp binding to RNA polymerase, high level trypsin resistance in the presence and absence of ppGpp was monitored. Trypsin digestion of RNA polymerase bound to ppGpp leads to protection of an N-terminal fragment of the beta'-subunit and a C-terminal fragment of the beta-subunit. We propose that the N terminus of beta' together with the C terminus of beta constitute a modular ppGpp binding site.
...
PMID:Binding of the transcription effector ppGpp to Escherichia coli RNA polymerase is allosteric, modular, and occurs near the N terminus of the beta'-subunit. 1103 17

The isolation of infectious salmon anaemia virus (ISAV) from asymptomatic wild fish species including wild salmon, sea trout and eel established that wild fish can be a reservoir of ISAV for farmed Atlantic salmon. This report characterizes the biological properties of ISAV isolated from a disease outbreak in farmed Coho salmon in Chile and compares it with ISAV isolated from farmed Atlantic salmon in Canada and Europe. The virus that was isolated from Coho salmon tissues was initially detected with ISAV-specific RT-PCR (reverse transcription-polymerase chain reaction). The ability of the virus to grow in cell culture was poor, as cytopathology was not always conspicuous and isolation required passage in the presence of trypsin. Virus replication in cell culture was detected by RT-PCR and IFAT (indirect fluorescent antibody test), and the virus morphology was confirmed by positive staining electron microscopy. Further analysis of the Chilean virus revealed similarities to Canadian ISAV isolates in their ability to grow in the CHSE-214 cell line and in viral protein profile. Sequence analysis of genome segment 2, which encodes the viral RNA polymerase PB1, and segment 8, which encodes the nonstructural proteins NS1 and NS2, showed the Chilean virus to be very similar to Canadian strains of ISAV. This high sequence similarity of ISAV strains of geographically distinct origins illustrates the highly conserved nature of ISAV proteins PB1, NS1 and NS2 of ISAV. It is noteworthy that ISAV was associated with disease outbreaks in farmed Coho salmon in Chile without corresponding clinical disease in farmed Atlantic salmon. This outbreak, which produced high mortality in Coho salmon due to ISAV, is unique and may represent the introduction of the virus to a native wild fish population or a new strain of ISAV.
...
PMID:Isolation and identification of infectious salmon anaemia virus (ISAV) from Coho salmon in Chile. 1141 49

Benign mesenchymal neoplasms associated with rearrangements of the DNA architectural factor gene HMGIC on chromosome 12 include lipomas, uterine leiomyomata, pulmonary chondroid hamartomas, endometrial polyps, salivary gland pleomorphic adenomas, and breast fibroadenomas. Although HMGIC also has been implicated in the pathobiology of aggressive angiomyxoma of the vulva, the molecular mechanisms pertaining to this neoplasm are unclear. Tissue from a recurrent aggressive angiomyxoma was investigated by cytogenetic and expression analysis for HMGIC and HMGIY. The trypsin-Giemsa-banded karyotype showed a clonal translocation between chromosomes 8 and 12 [46,XX,t(8;12)(p12;q15)]. Fluorescence in situ hybridization (FISH) analysis with whole chromosome paint probes for chromosomes 8 and 12 excluded cryptic involvement of other chromosomes. The chromosome 12 breakpoint was mapped with two-color FISH analysis using cosmid probes at the 5' and 3' termini of HMGIC. Both cosmid probes showed hybridization to the normal chromosome 12 and the der(12) chromosome, indicating that the breakpoint was 3' (telomeric) to the gene. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed HMGIC expression in the tumor, and immunohistochemistry localized HMGIC expression to the tumor's spindle cells. Like numerous benign mesenchymal tumors, this locally aggressive tumor is associated with rearrangements near or within HMGIC, but chimeric gene formation was not required for tumorigenesis. Inappropriate expression of this DNA binding protein, however, may be important in the pathobiology of this tumor. Understanding the pathogenetic mechanism may also be helpful in developing new diagnostic tools for identifying residual disease.
...
PMID:Chromosomal translocation t(8;12) induces aberrant HMGIC expression in aggressive angiomyxoma of the vulva. 1155 Feb 85

The heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) functions in the packaging of nascent RNA polymerase II transcripts and participates in a variety of nuclear and cytoplasmic processes that modulate gene expression. The RNA binding characteristics of hnRNP A1 suggest that it can modulate the expression of specific genes, but little is known about its possible targets in vivo. In this article, we show that hnRNP A1 interacts with the transcript of a cytochrome P450 gene, Cyp2a5, induced by xenobiotics and during liver damage. Binding of the hnRNP A1 to CYP2A5 mRNA was demonstrated by immunoprecipitation of the xenobiotic-stimulated (37/39 kDa) CYP2A5 mRNA-protein complex with a monoclonal anti-hnRNP A1 antibody, by partial trypsin digestion of the complex, and by showing that the RNA-protein complex is not formed with protein extracts from cells lacking the hnRNP A1. We also show that a specific hepatotoxic inducer of the Cyp2a5 gene, pyrazole, increases the cytoplasmic levels of hnRNP A1 in vivo. Finally, we show that hnRNP A1 can be overexpressed in mouse primary hepatocytes, leading to an accumulation of the CYP2A5 mRNA. Collectively, these results indicate that the hnRNP A1 is an important regulator of the Cyp2a5 gene.
...
PMID:Heterogeneous nuclear ribonucleoprotein A1 and regulation of the xenobiotic-inducible gene Cyp2a5. 1190 Dec 18

We have used synthetic oligomers of DNA and RNA to assemble nucleic acid scaffolds that, when mixed with T7 RNA polymerase, allow the formation of functional transcription complexes. Manipulation of the scaffold structure allows the contribution of each element in the scaffold to transcription activity to be independently determined. The minimal scaffold that allows efficient extension after challenge with 200 mm NaCl consists of an 8-nt RNA primer hybridized to a DNA template (T strand) that extends 5-10 nt downstream. Constructs in which the RNA-DNA hybrid is less than or greater than 8 bp are less salt-resistant, and the hybrid cannot be extended beyond 12-13 bp. Although the presence of a complementary nontemplate strand downstream of the primer does not affect salt resistance, the presence of DNA upstream decreases resistance. The addition of a 4-nt unpaired "tail" to the 5' end of the primer increases salt resistance, as does the presence of an unpaired nontemplate strand in the region that contains the 8-bp hybrid (thereby generating an artificial transcription "bubble"). Scaffold complexes having these features remain active for over 1 week in the absence of salt and exhibit many of the properties of halted elongation complexes, including resistance to salt challenge, a similar trypsin cleavage pattern, and a similar pattern of RNA-RNA polymerase cross-linking.
...
PMID:Characterization of T7 RNA polymerase transcription complexes assembled on nucleic acid scaffolds. 1235 56

Transcription of the ferric citrate transport system of Escherichia coli K-12 is mediated by the extracytoplasmic-function (ECF) sigma factor FecI, which is activated by ferric citrate in the growth medium. By using a bacterial two-hybrid system, it was shown in vivo that FecI binds to the beta' subunit of RNA polymerase. The inactive mutant protein FecI(K155E) displayed reduced binding to beta', and small deletions along the entire FecI protein led to total impairment of beta' binding. In vitro, FecI was retained on Ni(2+)-nitrilotriacetic acid agarose loaded with a His-tagged beta'(1-313) fragment and coeluted with beta'(1-313). Binding of FecI to beta' and beta'(1-313) was enhanced by FecR(1-85), which represents the cytoplasmic portion of the FecR protein that transmits the inducing signal across the cytoplasmic membrane. Interaction of FecR with FecI was demonstrated by showing that isolated FecR inhibited degradation of FecI by trypsin. This is the first demonstration of binding of an ECF sigma factor of the FecI type to the beta' subunit of RNA polymerase and of binding being enhanced by the protein that activates the ECF sigma factor.
...
PMID:The FecI extracytoplasmic-function sigma factor of Escherichia coli interacts with the beta' subunit of RNA polymerase. 1261 42

Trypsin and its specific inhibitor, TATI (tumour-associated trypsin inhibitor), are expressed in normal human pancreas and in a variety of tumours. The aim of the present study was to assess the parallel expression of trypsin and TATI in colorectal cancer, in comparison with their expression in normal epithelial tissue, since proteases and their inhibitors are thought to be co-expressed in malignant neoplasms. We also assessed the possible significance of their expression as a means of differentiation between normal and malignant tissue. We examined qualitatively and semi-quantitatively the immunohistochemical expression of trypsin and TATI on paraffin-embedded serial tissue sections from 91 colorectal adenocarcinomas. The reverse-transcriptase-polymerase-chain reaction (RT-PCR) was also performed on fresh malignant tissue from 55 of the above adenocarcinomas. Normal and non-malignant tissues adjacent to the tumours were also evaluated. Cytoplasmic expression of trypsin (more than 25% of the cancer cells positive) was found in 67 (73.6%) adenocarcinomas, whereas TATI was expressed in the cytoplasm of 59 (64.8%) cases studied. Statistical analysis using Spearman's test has demonstrated a significant correlation between trypsin and TATI immunohistochemical expression (p<0.01). RT-PCR showed co-expression of trypsin and TATI mRNA in all carcinomas studied. Distinct patterns of trypsin and TATI immunohistochemical expression were observed in adjacent, non-malignant tissues, where both trypsin and TATI mRNA were also detected. Normal tissues were negative by immunohistochemistry. Our results indicate co-expression of trypsin and TATI in colorectal tumours both at the mRNA and protein level. We conclude that in colorectal neoplasms, high levels of trypsin and TATI may be important for malignant tumour formation and/or metastatic process.
...
PMID:Co-expression of trypsin and tumour-associated trypsin inhibitor (TATI) in colorectal adenocarcinomas. 1297 86

A microbead-based affinity chromatography chip (micro-BACC) controlling hundreds of nanoliters of reaction volume was developed to separate and analyze hepatitis C virus (HCV) RNA polymerase protein by immobilization of an RNA aptamer on beads. A photocleavable linker was conjugated in between the beads and the aptamer to elute the bound RNA polymerase from the RNA aptamer in one step by UV irradiation, resulting in an efficient method to elute and identify the target molecule bound on RNA using a mass spectrometer. This linker showed a cleavage activity over 70% upon UV irradiation at 1050 mW/cm2 for more than 5 min. The photoelution method could prevent the target molecule from contaminations in affinity chromatography caused by elution solutions of high salt concentration, extreme pH and detergent, respectively. In this chip, sample reagents up to 800 nL could be metered quantitatively into the bead chamber using a nanoliter dispenser working, based on surface-guided flow control and pneumatic control by external air pressure on the chip. RNA polymerase eluted after UV irradiation was successfully analyzed by trypsin treatment without additional purification. As a result, using the aptamer, we could detect RNA polymerase from 800 nL hepatitis C patient serum containing 96 fmol HCV RNA polymerase. The detection limit of this system was estimated to be 9.6 fmol HCV RNA polymerase.
...
PMID:Microbead-based affinity chromatography chip using RNA aptamer modified with photocleavable linker. 1556 96

To determine whether common helminth infections could modify the intestinal immunopathological status of the host, the expression in the human duodenal mucosa of cytokines, eosinophil- and mast-cell-specific molecules and monosaccharide transporters of the glucose-transporter (GLUT) family was explored. The 31 subjects were all patients at the gastro-intestinal disease unit of Nongkhai Hospital, Thailand. Four of the 10 patients who presented with eosinophilia (> or = 6.0% of their leucocytes were eosinophils), and five of the other 21 patients, had intestinal infections with helminths when they presented or within the previous 3 months. Studies based on semi-quantitative, reverse-transcriptase PCR revealed that the interleukin-5/interferon-gamma ratio was significantly higher in the noneosinophilic, helminth-infected patients than in the non-eosinophilic, uninfected patients, whereas the IgE receptor type I (Fc epsilon RI)/mast-cell tryptase ratio was significantly higher in the eosinophilic, helminth-infected patients than in the eosinophilic, uninfected patients. Expression of Charcot-Leyden-crystal protein, GLUT-1 and GLUT-5, however, showed no significant inter-group differences. Principal-components analysis of the data on eosinophils, interleukin-5, interferon-gamma, Fc epsilon RI and mast-cell tryptase revealed that one principal component could discriminate the patients who had helminth infection from the non-eosinophilic, uninfected patients, but not from the eosinophilic, uninfected patients. These results indicate that, whatever the intestinal pathology, patients infected with common intestinal helminths tend to develop a mucosal immunological response of the Th2 type.
...
PMID:Immunological characteristics of patients infected with common intestinal helminths: results of a study based on reverse-transcriptase PCR. 1570 Dec 58

We sought to determine whether hepatic side population (SP) cells derived from adult human liver possess the potential of a novel candidate hepatic stem cell. Human cadaveric donor liver was subjected to collagenase perfusion and hepatocytes were separated from nonparenchymal cells by differential centrifugation. SP cells were isolated from the nonparenchymal portion after Hoechst 33342 staining. Since CD45 is a panleukocyte antigen, CD45-negative SP cells were separated from the vast majority of CD45-positive SP cells (90%), and hepatic growth medium was used to culture both groups. Both CD45-negative and CD45-positive hepatic SP cells generated colonies in the hepatic growth medium in 2-3 weeks. The colonies yielded large cells morphologically consistent with human hepatocytes, demonstrating granule-rich cytoplasm, dense, often double nuclei, and intracellular lipofuscin pigment. The cultured cells from both sources were positive for markers of human hepatocytes: HepPar, cytokeratin 8 (CK8), and human albumin. Reverse transcriptase-polymerase chain reaction (RT-PCR) performed on both groups demonstrated positivity for additional liver markers including human albumin, CK18, alpha-1 anti-trypsin, and the human cytochrome P450 enzyme CYP2B6. Double immunostaining (CD45 and HepPar) and RT-PCR confirmed that the hepatocyte-like cells derived from the CD45-negative SP cells acquired HepPar positivity but had no detectable CD45 antigen expression. In contrast, the cultured cells derived from the CD45-positive SP cells also acquired HepPar positivity, but only a minimal fraction expressed the CD45 antigen. We conclude that hepatic SP cells derived from the nonparenchymal portion of human liver are a potential source of human hepatocytes irrespective of their CD45 status, and further animal studies will be required to assess their regenerative potential.
...
PMID:Side population cells derived from adult human liver generate hepatocyte-like cells in vitro. 1618 69


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

---