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

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

A 200-fold inhibition in the titer of infectious vesicular stomatitis virus (VSV) was produced in cultures of Ly cells treated with 30 reference units of interferon per milliliter. Virus particle production, as measured by VSV particle-associated transcriptase, or nucleocapsid protein was inhibited by a maximum of tenfold. The glycoprotein and membrane protein content was reduced in VSV derived from interferon-treated cells. Thus interferon-treated cells may have produced VSV particles with low infectivity, which may be related to the reduced amount of glycoprotein incorporated into such particles. These findings resemble those reported in interferon-treated cells infected with murine leukemia viruses.
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PMID:Selective inhibition of glycoprotein and membrane protein of vesicular stomatitis virus from interferon-treated cells. 624 16

A systematic and comparative study was performed on the polypeptide composition and the RNA polymerase activity associated with virions of various strains of influenza A virus, including four human and two avian viruses. Significant differences were found in the molecular weights of not only hemagglutinin (HA) but also both nucleoprotein (NP) and membrane protein (M), as determined by polyacrylamide gel electrophoresis under denaturing conditions. The results indicate that, among viruses sharing the same serotype determined by the surface proteins HA and NA (neuraminidase), considerable variations exist in the structure of viral proteins, including inner proteins. The relative contents of viral proteins also varied among these strains grown under similar conditions. The total content of three P proteins, the putative RNA polymerase subunits, was within the range between 1.1 and 2.2% of total viral proteins and roughly paralleled the virion-associated RNA polymerase activity. The virion-associated RNA polymerase of all the strains tested were stimulated by the same dinucleotide primers, ApG or GpG, indicating that the specificity of transcription initiation is conserved among wide varieties of influenza virus.
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PMID:RNA polymerase of influenza virus. I. Comparison of the virion-associated RNA polymerase activity of various strains of influenza virus. 627 72

The ompA protein, an outer membrane protein required for conjugation, is one of the most abundant proteins in Escherichia coli. The structural gene for the ompA protein cloned in a plasmid vector, pMF21, conferred sensitivity to ompA protein-specific phages. We have determined the DNA sequence of a fragment of 533 base pairs encompassing the regulatory region of the ompA gene: the promoter region, the 5'-untranslated region, and the region corresponding to the signal peptide for this secretory protein. The promoter region has a sequence that is remarkably homologous with the lac and gal promoters. Particularly, both the ompA and gal promoters have the same octanucleotide sequence, T-C-A-C-A-C-T-T, in their RNA polymerase recognition site, which has been shown to be involved in the binding of cyclic AMP receptor protein to the gal promoter. Analogous with the observations in the gal operon, a specific RNA transcript was produced only when glycerol, a DNA-destabilizing agent, was added to a cell-free system directed by a DNA fragment of the ompA gene. These data indicate that the ompA mRNA has an untranslated region at the 5' end of about 140 nucleotides. In this region there are two additional initiation codons (II and III) besides the initiation codon (I) for the pro-ompA protein. AUG-III is located 30 bases upstream from AUG-I and accompanies a ribosome-binding site. Therefore, AUG-III is likely to begin the synthesis of a pentapeptide. The termination codon for the peptide overlaps with AUG-II, so that the ribosomes could reinitiate from AUG-II without being released from the mRNA. This reinitiation leads to the synthesis of a heptapeptide. The termination codon for this peptide also overlaps with AUG-I, which initiates the production of the pro-ompA protein. Because AUG-I also has an adjacent ribosome-binding site, the tandem repeat of initiation codons and ribosome-binding sites may be an important mechanism for facilitating the rate of initiation of translation. Extensive secondary structures exist in the 5' end as well as in the coding region of the ompA mRNA, which may also play a role in the function of the mRNA.
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PMID:Regulatory region of the gene for the ompA protein, a major outer membrane protein of Escherichia coli. 700 45

We have analyzed the molecular mechanism of regulation of the ferric dicitrate transport system in Escherichia coli (Ec), by studying the transcription of the regulatory and structural genes under various environmental conditions, and by determining the location of their transcriptional start points and promoter regions. We report here that the main species observed in Northern hybridization analyses were a 2.5-kb mRNA, encoded by the outer membrane protein receptor gene fecA, and a 1.5-kb mRNA encoded by a region including the fecIR genes. The synthesis of the 2.5-kb fecA mRNA is regulated by both citrate and iron. Furthermore, transcription of fecA is dependent on the presence of FecI. The promoter region for the fecA mRNA, a likely site of action for FecI, is not related to the consensus promoter region for sigma 70 RNA polymerase in Ec K-12. However, it shows greatest similarity with promoters of genes regulated by a new sub-family of sigma factors, i.e., the extracytoplasmic function (ECF) sigma factors, which are associated with the expression of genes involved in extracytoplasmic functions, suggesting that FecI may act as a specialized sigma factor. We also show that the fecB,C,D,E transport genes are linked in operon fashion to fecA. Since the levels of the fecB,C,D,E RNAs are extremely low, as compared to the level of fecA mRNA, it is likely that processing from the 3' end must occur and stop near the end of fecA where a hairpin structure is located.
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PMID:Transcription of the region encoding the ferric dicitrate-transport system in Escherichia coli: similarity between promoters for fecA and for extracytoplasmic function sigma factors. 755 62

Osmoregulated porin gene expression in Escherichia coli is controlled by the two-component regulatory system EnvZ and OmpR. EnvZ, the osmosensor, is an inner membrane protein and a histidine kinase. EnvZ phosphorylates OmpR, a cytoplasmic DNA-binding protein, on an aspartyl residue. Phospho-OmpR binds to the promoters of the porin genes to regulate the expression of ompF and ompC. We describe the use of limited proteolysis by trypsin and ion spray mass spectrometry to characterize phospho-OmpR and the conformational changes that occur upon phosphorylation. Our results are consistent with a two-domain structure for OmpR, an N-terminal phosphorylation domain joined to a C-terminal DNA-binding domain by a flexible linker region. In the presence of acetyl phosphate, OmpR is phosphorylated at only one site. Phosphorylation induces a conformational change that is transmitted to the C-terminal domain via the central linker. Previous genetic analysis identified a region in the C-terminal domain that is required for transcriptional activation. Our results indicate that this region is within a surface-exposed loop. We propose that this loop contacts the alpha subunit of RNA polymerase to activate transcription. Mass spectrometry also reveals an unusual dephosphorylated form of OmpR, the potential significance of which is discussed.
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PMID:Phosphorylation-dependent conformational changes in OmpR, an osmoregulatory DNA-binding protein of Escherichia coli. 756 33

In a mucB (algN) genetic background, insertion of an omega element approximately 200 bp downstream of glpD, encoding sn-glycerol-3-phosphate dehydrogenase from Pseudomonas aeruginosa, had an adverse effect on alginate biosynthesis from various carbon sources. The insertion inactivated glpM, a gene encoding a 12,040-M(r) hydrophobic protein containing 109 amino acids. This protein, which was expressed in a T7 RNA polymerase expression system, appears to be a cytoplasmic membrane protein.
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PMID:Identification of Pseudomonas aeruginosa glpM, whose gene product is required for efficient alginate biosynthesis from various carbon sources. 764 8

cDNA species encoding either the long or the short isoforms of the rat thyrotropin-releasing-hormone (TRH) receptor were expressed stably in Rat 1 fibroblasts, and clones expressing specific binding of [3H]TRH were detected and expanded. Clones expressing each of these receptors at levels up to 1 pmol/mg of membrane protein were selected for analysis. Reverse-transcriptase PCR on RNA isolated from these clones confirmed that each clone expressed only mRNA corresponding to the expected splice variant. Both receptor splice variants bound [3H]TRH with a Kd of some 80 nM when binding assays were performed in the presence of guanosine 5'-[beta gamma-imido]-triphosphate. In the presence of TRH, both receptor subtypes were able to cause stimulation of inositol phosphate generation in a pertussis-toxin-insensitive manner with similar EC50 values and to stimulate the mobilization of intracellular Ca2+, but, despite reports that TRH receptors can also interact with the G-proteins Gs and Gi2, neither receptor splice variant was able to modulate adenylate cyclase activity in either a positive or a negative manner. These data indicate that the long and short isoforms of the rat TRH receptor have similar affinities for TRH and display similar abilities to interact with the Gq-like G-proteins, but show no ability to regulate adenylate cyclase, at least when expressed in this genetic background.
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PMID:Comparison of the signalling properties of the long and short isoforms of the rat thyrotropin-releasing-hormone receptor following expression in rat 1 fibroblasts. 764 58

Epstein-Barr virus (EBV) is frequently found in Hodgkin and Reed-Sternberg cells in Hodgkin's disease. Epstein-Barr virus has transforming properties in vitro and might be involved in the pathogenesis of certain types of Hodgkin's disease. One of the possible mechanisms is the upregulation of the human proto-oncogene bcl-2 by the latent membrane protein 1 of EBV in vitro. Another possibility might be the expression of the viral 'bcl-2 homologue' BHRF-1. In the present study of 64 cases of Hodgkin's disease we investigated the expression of bcl-2 at the protein level in relation to the presence of EBV. Moreover, in 10 EBV positive cases we investigated, the expression of the bcl-2 homologue, BHRF-1, by reverse-transcriptase PCR. bcl-2 was detected in 14 of 22 (64%) EBV positive and in 37 of 42 (88%) EBV negative cases. In 17 of 22 (77%) EBV positive cases Reed-Sternberg cells were negative (n = 8) or expressed the bcl-2 protein in a very low percentage ( < 5%) of cells (n = 9), whereas in 20 of 42 (43%) of the EBV negative cases the majority ( > 50%) of the neoplastic cells were bcl-2 positive. Using the reverse-transcriptase PCR with primers amplifying transcripts of BHRF-1 we were able to detect BHRF-1 transcripts in only one of the 10 tested cases of EBV positive Hodgkin's disease. Our data indicate that in EBV positive Hodgkin's disease growth advantage of Reed-Sternberg cells is not obtained by upregulation of bcl-2 or by the EBV homologue BHRF-1.
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PMID:Expression of bcl-2 protein and transcription of the Epstein-Barr virus bcl-2 homologue BHRF-1 in Hodgkin's disease: implications for different pathogenic mechanisms. 884 76

The genome of Lelystad virus (LV), a positive-strand RNA virus, is 15 kb in length and contains 8 open reading frames (ORFs) that encode putative viral proteins. ORFs 2 to 7 were cloned in plasmids downstream of the Sp6 RNA polymerase promoter, and the translation of transcripts generated in vitro yielded proteins that could be immunoprecipitated with porcine anti-LV serum. Synthetic polypeptides of 15 to 17 amino acids were selected from the amino acid sequences of ORFs 2 to 7 and antipeptide sera were raised in rabbits. Antisera that immunoprecipitated the in vitro translation products of ORFs 2 to 5 and 7 were obtained. Sera containing antibodies directed against peptides from ORFs 3 to 7 reacted positively with LV-infected alveolar lung macrophages in the immunoperoxidase monolayer assay. Using these antipeptide sera and porcine anti-LV serum, we identified three structural proteins and assigned their corresponding genes. Virions were found to contain a nucleocapsid protein of 15 kDa (N), an unglycosylated membrane protein of 18 kDa (M), and a glycosylated membrane protein of 25 kDa (E). The N protein is encoded by ORF7, the M protein is encoded by ORF6, and the E protein is encoded by ORF5. The E protein in virus particles contains one or two N-glycans that are resistant to endo-beta-N-acetyl-D-glucosaminidase H. This finding indicates that the high-mannose glycans are processed into complex glycans in the Golgi compartment. The protein composition of the LV virions further confirms that LV is evolutionarily related to equine arteritis virus, simian hemorrhagic fever virus, and lactate dehydrogenase-elevating virus.
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PMID:Characterization of proteins encoded by ORFs 2 to 7 of Lelystad virus. 783 70

Recent evidence suggests that a number of non-phagocytic cell types may contain a superoxide generating NADPH oxidase. Studies to data on cultured human fibroblasts have primarily concerned the identification of cytochrome b558, whilst expression of other NADPH oxidase components have not been addressed. In this study we have investigated the expression of NADPH oxidase with particular reference to the cytosolic factors p47-phox and p67-phox. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed that human fibroblasts express mRNA for p47-phox, p67-phox and p22-phox. Expression of the gp91-phox transcript was not detected, indicating that human fibroblasts may possess an NADPH oxidase isoenzyme. Western blot analysis of human fibroblast cytosol, using an anti-p47-phox antibody (JW-1), identified a 47 kDa protein. Cell-free reconstitution assays showed that fibroblast cytosol could initiate superoxide generation when mixed with either human fibroblast membranes (0.16 nmol superoxide/min/microgram membrane protein), or resting human neutrophil membranes (0.20 nmol superoxide/min/microgram membrane protein). These data indicate that the expression of p47-phox and p67-phox by human fibroblasts may contribute to the cells' generation of superoxide.
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PMID:The functional expression of p47-phox and p67-phox may contribute to the generation of superoxide by an NADPH oxidase-like system in human fibroblasts. 798 96


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