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)

Reverse transcriptase activity was measured by incorporation of dUMP linked to digoxigenin into a suitable template-primer molecule. Incorporation was monitored by using peroxidase-conjugated Fab fragments directed against digoxigenin. The standard assay measuring incorporation of radiolabeled nucleotides into acid-precipitable material was compared with this new immunochemical assay with regard to its usefulness for testing inhibitors of reverse transcriptase.
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PMID:Measurement of HIV-1 reverse transcriptase by a nonradioactive assay system. 128 11

We have developed general methods for joining together, via cleavable disulfide bonds, either two unprotected polynucleotides or a polynucleotide and a peptide or protein. To join two oligonucleotides, each is first converted to an adduct in which cystamine is joined to the 5'-terminal phosphate of the oligonucleotide by a phosphoramidate bond. The adducts are mixed and reduced with dithiothreitol. The dithiothreitol is then removed by dialysis. Oxidation by atmospheric oxygen occurs to yield the required dimer. To join an oligonucleotide to a cysteine-containing peptide or protein, the 5'-cystamine oligomer is first converted to a 2'-pyridyldisulfide adduct and then reacted with an excess of the peptide or protein. If the peptide does not contain a free cysteine residue, it is first treated with iminothiolane to introduce one or more sulfhydryl groups. We have used these procedures to join a 16 mer deoxynucleotide probe and MDV-1 RNA, a substrate of Q beta RNA polymerase. This adduct hybridizes with a complementary target DNA. We have also joined a 16mer probe to peroxidase and MDV-1 RNA to human IgG. The probe-peroxidase adduct maintains enzymatic activity and the MDV-1 RNA-IgG adduct binds to a complementary anti-IgG.
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PMID:Ligation of oligonucleotides to nucleic acids or proteins via disulfide bonds. 337 70

The localization of foot-and-mouth disease viral-induced RNA polymerase has been determined in situ and in partially fractionated cell components by using polymerase antisera tagged with either peroxidase or ferritin. Electron microscopic examination revealed the polymerase to be heavily concentrated on membranes of the smooth membranous vacuoles (SMV) which are newly formed during infection and which were previously shown to be the site where newly synthesized viral RNA appeared. Polymerase antigen was also seen to be associated with the endoplasmic reticulum (ER), the assumed site of original synthesis, and to a lesser extent with mitochondria and the Golgi apparatus. There was no significant polymerase attachment to nuclear and plasma membranes.
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PMID:Association of foot-and-mouth disease virus induced RNA polymerase with host cell organelles. 631 90

A simple multiplex riboprobe system for detection of virulent Yersinia enterocolitica was developed using a pool of RNA probes specific for various chromosomal and plasmid-borne virulence gene sequences (yadA, virC, ail and yst). Riboprobes were synthesized by a rapid, simple and efficient technique involving in vitro transcription of polymerase chain reaction-generated templates incorporating bacteriophage T7 RNA polymerase promoter sequences in one of the priming oligonucleotides. After dot blotting target DNA samples on nitrocellulose and hybridization with the riboprobes, the RNA: DNA hybrids formed were detected by a simple immunoenzymic assay involving sequential reactions with an anti-RNA : DNA hybrid monoclonal antibody, anti-mouse Ig-peroxidase conjugate and chromogenic or chemiluminescent enzyme substrate solution. This multiplex riboprobe system targeting both chromosomal and plasma-borne sequences permitted detection of virulent Y. enterocolitica, regardless of plasmid loss during handling of cultures, and was unreactive with a virulent Y. enterocolitica, other Yersinia and other bacteria. This system resulted in a significant improvement in the limit of detection in comparison to that obtained with individual probes.
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PMID:Multiplex riboprobes for the detection of virulent Yersinia enterocolitica and simple methods for their preparation. 759 16

Using the T7 RNA polymerase expression system, a modified plasmid vector has been developed which gives reliable, high level expression in Escherichia coli of the gene encoding streptococcal NADH peroxidase. The recombinant enzyme has been purified to homogeneity using a revised protocol which yields over 35 mg of pure protein per liter of culture. Recombinant NADH peroxidase is fully active and exhibits spectroscopic and redox properties identical to those for the enzyme purified from Streptococcus faecalis 10C1. Reductive titrations and thiol analyses confirm the presence of the unusual cysteine-sulfenic acid (Cys-SOH) redox center identified previously. N-terminal sequence analysis, analytical gel filtration, and preliminary x-ray diffraction data all confirm the structural identity of the recombinant and S. faecalis enzymes. Steady-state kinetic analysis of the peroxidase, coupled with results from static titration experiments is consistent with a limiting type of ternary complex mechanism and allows the determination of many of the corresponding kinetic constants. In addition, preliminary 1H NMR spectra of the enzyme at millimolar concentrations show good dispersion in the amide region and indicate that the recombinant peroxidase is suitable for one-dimensional NMR work with labeled amino acids.
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PMID:Purification and analysis of streptococcal NADH peroxidase expressed in Escherichia coli. 842 93

There is evidence suggesting the importance of the interleukin-1 receptor type I (IL-1Rtl) and interleukin-1 beta (IL-1 beta) as mediator in local intercellular interactions in endometrial tissue and embryonic implantation. To complete our understanding of the entire endometrial IL-1 system in humans, we have investigated the immunohistochemical distribution of IL-1 receptor antagonist (IL-1ra) in the human endometrium throughout the menstrual cycle. We have also identified the forms of IL-1ra present in human endometrial cells. Immunoreactive IL-1ra was found in both cryostat and paraffin-embedded sections of human endometrium using the alkaline phosphatase-peroxidase (A-P) method with two different IL-1ra antibodies. IL-1ra was present throughout the entire menstrual cycle, located primarily in the endometrial epithelium. However, IL-1ra staining was significantly higher during follicular phase in comparison with early and mid-late luteal phases. Reverse transcriptase polymerase chain reaction of cultured stromal and glandular cells showed that these cells express the intracellular form of IL-1ra mRNA (icIL-1ra). Our results demonstrate the regulated presence of the icIL-1ra in the human endometrium. This finding supports a possible autocrine-paracrine role for the IL-1 system in the human endometrium and embryonic implantation.
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PMID:Immunohistochemical localization, identification and regulation of the interleukin-1 receptor antagonist in the human endometrium. 853 Jun 93

Using a one-step reaction, a bifunctional compound was synthesized for detecting histidine-tagged proteins immobilized on nitrocellulose. This compound has a biotin as one functional group and a nitrilotriacetic acid as the other. The nitrilotriacetic acid is used to chelate a Ni(II) ion at four of its six coordination sites. The remaining two sites are available for binding to a histidine tag. The biotin functional group can then be detected using a streptavidin-horseradish peroxidase conjugate and chemiluminescence. Using this biotinylated nitrilotriacetic acid, it is possible to detect less than 0.11 pmol of histidine-tagged Escherichia coli RNA polymerase sigma70 subunit. This reagent is also able to specifically detect His-tagged sigma70 from a whole cell lysate following SDS-PAGE and transfer to nitrocellulose. The reagent can be dissociated from the His-tagged protein at pH 4.8 and the blot can be reprobed with a monoclonal antibody for detection of different proteins on the same blot.
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PMID:Single-step synthesis and characterization of biotinylated nitrilotriacetic acid, a unique reagent for the detection of histidine-tagged proteins immobilized on nitrocellulose. 861 73

Marrow stromal cells mediate the effect of 1alpha,25-dihydroxyvitamin D3 on formation of osteoclast-like cells from undifferentiated hematopoetic precursors in bone marrow. Induction by the vitamin D hormone of multinucleated, calcitonin receptor- and tartrate-resistant acid phosphatase-positive cells in primary mouse bone marrow culture can be modulated by other members of the steroid/thyroid hormone family, such as triiodothyronine, which has a positive effect, as well as 17beta-estradiol and 5alpha-dihydrotestosterone, which both act as inhibitors of osteoclastogenesis. In an attempt to relate these effects of the steroid/thyroid hormones to the presence of their respective nuclear receptors, we studied expression of the vitamin D receptor (VDR), estrogen receptor (ER)-alpha and -beta, thyroid hormone receptor (TR)-alpha and -beta, and androgen receptor (AR) in total bone marrow as well as primary marrow stromal cell cultures. By using reverse-transcriptase-polymerase chain reaction, in both cases amplification products were obtained, which were identified by multiple restriction fragment length analysis as transcripts from mRNA specific for the ligand-binding domains of the VDR, ER-alpha, ER-beta, TR-alpha, TR-beta, and AR. Specific immunostaining by indirect peroxidase labeling revealed that among the various cell types present in bone marrow, the steroid/ thyroid hormone receptors are abundant particularly in marrow stromal cells. In another series of experiments, we extended our survey on receptor expression also to stromal/osteoblastic cell lines. At the mRNA level, the complete repertoire of steroid/thyroid hormone receptors was present in preadipocytic ST2 cells as well as in osteoblastic MC3T3-E1 cells. By immunocytochemical staining of the latter, it became apparent that single cells exhibit wide variations in intensity of specific signals for all the receptors investigated, so that, notably in contrast to primary stromal cells and ST2 cells, MC3T3-E1 display a mosaic pattern of receptor protein expression.
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PMID:Expression of the vitamin D receptor, of estrogen and thyroid hormone receptor alpha- and beta-isoforms, and of the androgen receptor in cultures of native mouse bone marrow and of stromal/osteoblastic cells. 1032 6

A cDNA clone encoding the Prx7 peroxidase from barley (Hordeum vulgare L.) predicted a 341-amino acid protein with a molecular weight of 36,515. N- and C-terminal putative signal peptides were present, suggesting a vacuolar location of the peroxidase. Immunoblotting and reverse-transcriptase polymerase chain reaction showed that the Prx7 protein and mRNA accumulated abundantly in barley coleoptiles and in leaf epidermis inoculated with powdery mildew fungus (Blumeria graminis). Two isoperoxidases with isoelectric points of 9.3 and 7.3 (P9.3 and P7.3, respectively) were purified to homogeneity from barley coleoptiles. P9.3 and P7.3 had Reinheitszahl values of 3.31 and 2.85 and specific activities (with 2,2'-azino-di-[3-ethyl-benzothiazoline-6-sulfonic acid], pH 5.5, as the substrate) of 11 and 79 units/mg, respectively. N-terminal amino acid sequencing and matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry peptide analysis identified the P9. 3 peroxidase activity as due to Prx7. Tissue and subcellular accumulation of Prx7 was studied using activity-stained isoelectric focusing gels and immunoblotting. The peroxidase activity due to Prx7 accumulated in barley leaves 24 h after inoculation with powdery mildew spores or by wounding of epidermal cells. Prx7 accumulated predominantly in the epidermis, apparently in the vacuole, and appeared to be the only pathogen-induced vacuolar peroxidase expressed in barley tissues. The data presented here suggest that Prx7 is responsible for the biosynthesis of antifungal compounds known as hordatines, which accumulate abundantly in barley coleoptiles.
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PMID:Barley coleoptile peroxidases. Purification, molecular cloning, and induction by pathogens. 1036 1

To explore the oxygen response regulators involved in thiol peroxidase gene (tpx) expression in Escherichia coli, we constructed a single-copy tpx-lacZ operon fusion and monitored tpx-lacZ expression in various genetic backgrounds. Expression of the tpx-lacZ fusion was increased 4-fold by aerobic growth. Anaerobic expression of tpx-lacZ in either (delta)arcA or delta(fnr) strains was 2.5-fold depressed compared with that of the wild-type strain. The results of immunoblotting experiments also demonstrated that ArcA and Fnr regulatory proteins repressed thiol peroxidase gene expression during anaerobic growth. Inspection of the tpx promoter region revealed putative binding sites for ArcA and Fnr. It thus appears that ArcA and Fnr function as repressors by blocking the binding of RNA polymerase to the tpx promoter in E. coli under anaerobic growth conditions.
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PMID:Involvement of ArcA and Fnr in expression of Escherichia coli thiol peroxidase gene. 1079


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