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)

Transcriptionally amplified DNA probes are valuable tools in the development of sensitive nucleic acid-based diagnostic assays. Here we describe a model assay using a novel oligonucleotide hairpin probe that encodes a T7 RNA polymerase promoter. The hairpin probe and an adjacently hybridizing biotinylated capture probe were hybridized to target DNA and the duplex was captured onto streptavidin-coated magnetic particles. After ligation of the immobilized probes, which served to maintain specificity, the hairpin probe was transcribed by T7 RNA polymerase. The amplified RNA product was hybridized to the capture probe and bound to the streptavidin-coated magnetic particles. The immobilized heteroduplex was detected with an antibody-alkaline phosphatase conjugate specific for DNA:RNA hybrids, and the chemiluminescent substrate adamantyl-1,2-dioxetane phenyl phosphate. Ten attomoles of target DNA could be detected in a background of 5 micrograms of unrelated DNA. The chemiluminescent immunoassay was as sensitive as radioactive detection of specific product after gel electrophoresis.
...
PMID:A transcriptionally amplified DNA probe assay with ligatable probes and immunochemical detection. 837 77

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.
...
PMID:Immunohistochemical localization, identification and regulation of the interleukin-1 receptor antagonist in the human endometrium. 853 Jun 93

DNA templates suitable for direct synthesis of RNA probes are produced by the polymerase chain reaction. The nucleic acid sequence of interest is amplified using a downstream primer carrying the T7 RNA polymerase promoter sequence. The modified primer is incorporated into the amplified DNA, which is subsequently used for RNA probe synthesis in the presence of T7 RNA polymerase and a hapten-labeled ribonucleotide (digoxigenin-UTP). As a model, we prepared RNA probes specific for the BCR-ABL mRNA characteristic of chronic myelogenous leukemia. The probes are used in time-resolved fluorometric hybridization assays. Mixtures of BCR-ABL positive and negative cells, as well as whole blood samples, are analyzed. The sample mRNA is amplified using a biotinylated upstream primer. The amplified product (target DNA) is captured onto streptavidin-coated wells and hybridized to the RNA probe. The hybrids are detected with an alkaline phosphatase (ALP)-labeled antibody. ALP hydrolyzes the phosphate ester of fluorosalicylic acid, and the fluorosalicylate produced forms highly fluorescent ternary complexes with Tb(3+)-EDTA, which can be quantified by measuring the Tb3+ fluorescence in a time-resolved mode. As low as 0.4 fmol of target DNA can be detected. Also, a single leukemic cell may be detected in the presence of 0.5 million "normal" cells.
...
PMID:Time-resolved fluorometric hybridization assays with RNA probes synthesized from polymerase chain reaction-generated DNA templates. 884 29

Three clonally related T-cell lymphoma lines (PB-1, 2A, and 2B) were examined for expression of IL-2, IL-4, and their receptors. All three lines were derived from a single patient who had an atypical, progressive T-cell lymphoproliferative disorder involving primarily skin (Davis, T.H. et al. 1992, N. Engl. J. Med. 326:1115). The PB-1 cell line was obtained from a relatively early, clinically indolent stage of the cutaneous lymphoma, whereas the 2A and 2B lines were established from a late, aggressive stage of the lymphoma. Reverse-transcriptase PCR performed with primer pairs specific for IL-2 and IL-4 showed that no mRNA coding for these cytokines was present in any of the lines with the exception of IL-4 mRNA in the 2A line. No IL-4 protein, however, was found in any of the cell lines including 2A by immunocytochemical staining with anti-IL-4 mAb. Accordingly, no bioactive IL-4 was present in the supernatants of these lines. In contrast, all three T-cell lymphoma lines contained mRNA for IL-2R alpha, IL-2R beta, IL-4R and common gamma chain. Immunocytochemical analysis revealed that only the PB-1 line stained strongly with mAbs specific for IL-2R alpha, IL-2R beta, and IL-4R whereas the 2A and 2B lines showed only limited staining with these mAbs. In contrast to expression of IL-2R alpha and IL-4R primarily on the cell surface, IL-2R beta was localized mainly in the cell cytoplasm. Testing supernatants of the cell lines by ELISA for the presence of soluble alpha chain of the IL-2R (sIL-2R) has shown that only PB-1 secreted a large amount of sIL-2R, whereas the 2A and 2B lines secreted lesser amounts. Furthermore, the PB-1 cells expressed a relatively large number of IL-4R as determined by IL-4 binding studies using an IL-4-alkaline phosphatase fusion protein. The remaining two lines displayed only limited binding of IL-4. Addition of IL-2 and/or IL-4 to the culture medium did not modulate growth of PB-1 and the other two lines. These findings may indicate that at least some types of T-cell lymphoma evolve from cells which lose the capacity to synthesize T-cell autocrine growth factors such as IL-2 and IL-4, and show progressive loss of receptors for these cytokines.
...
PMID:Analysis of IL-2, IL-4 and their receptors in clonally-related cell lines derived from a patient with a progressive cutaneous T-cell lymphoproliferative disorder. 902 95

The nucleotide sequence relatedness between the chromosome of Salmonella typhi and the virulence plasmid of Salmonella enteritidis was investigated using short DNA probes of < 2 kb covering the whole virulence plasmid sequence. Only one homologous region was detected. This region was subsequently cloned and partially sequenced. Sequences closely related to the pefl gene and the ORFs orf7, orf8 and orf9, which are located downstream of the fimbrial pef operon of the Salmonella typhimurium virulence plasmid, were detected. Sequencing of the cloned S. typhi DNA fragment also revealed identity with genes of the fimbrial sef operon characterized in the chromosome of S. enteritidis. These nucleotide sequences mapped upstream of the S. typhi chromosomal region homologous to the S. enteritidis virulence plasmid. The general organization of the cloned S. typhi chromosomal fragment was similar to the fimbriae-encoding region of the S. typhimurium virulence plasmid. The deduced product of orf8 in the S. typhimurium virulence plasmid, as well as those of the corresponding ORFs in the homologous region of the S. typhi chromosome and in the S. enteritidis virulence plasmid (designated dlt and dlp, respectively), appeared to be related to the thioredoxin family of thiol: disulphide oxidoreductases. The dlp gene was able to complement the DTT-sensitive phenotype, the inability to metabolize glucose 1-phosphate and the low alkaline phosphatase activity of a dsbA mutant of Escherichia coli. The dlt gene partially complemented the lack of alkaline phosphatase activity, but not the other mutant phenotypes. The products of both genes could be detected using the T7 RNA polymerase promoter expression system. The estimated molecular masses of the products of the dlt and dlp genes by SDS-PAGE were 26 and 23 kDa, respectively, the first being in agreement with the deduced amino acid sequence and the latter, somewhat smaller. The processing of a possible leader peptide in the Dlp protein, but not in the Dlt protein, could be responsible for this difference. The Dlp protein appeared as a doublet band on SDS-PAGE, which is characteristic of the oxidized and reduced states of this kind of protein.
...
PMID:Homologous regions of the Salmonella enteritidis virulence plasmid and the chromosome of Salmonella typhi encode thiol: disulphide oxidoreductases belonging to the DsbA thioredoxin family. 914 3

p64 is a protein identified as a chloride channel by biochemical purification from kidney microsomes. We expressed p64 in HeLa cells using a recombinant vaccinia virus/T7 RNA polymerase driven system. Total cell membranes were prepared from infected/transfected cells and fused to a planar lipid bilayer. A novel chloride channel activity was found in cells expressing p64 and not in control cells. The p64-associated activity shows strong anion over cation selectivity. Single channels show prominent outward rectification with single channel conductance at positive potentials of 42 pS. The chloride channel activity is activated by treatment of the membranes with alkaline phosphatase and inhibited by DNDS and by TS-TM calix(4)arene. Whole membrane anion permeability was determined by a chloride efflux assay, revealing that membranes from cells expressing p64 showed a small but highly significant increase in chloride permeability, consistent with expression of a novel chloride channel activity.
...
PMID:Functional expression of p64, an intracellular chloride channel protein. 959 76

The RNA polymerase VP1 of IPNV (a bisegmented dsRNA containing virus) is present in the virion both as a free polypeptide and as a genome-linked protein (VPg). Virion VP1 primes viral RNA synthesis in vitro (P. Dobos, 1995, Virology 208, 19-25), and here we present data which suggest that protein-primed RNA synthesis may also take place in infectious pancreatic necrosis virus (IPNV)-infected cells. Anti-VP1 serum immunoprecipitated several polypeptides larger than the 94-kDa VP1 of IPNV from [35S]methionine-labeled infected cell lysates. During denaturing, SDS-polyacrylamide gel electrophoresis these polypeptides formed a characteristic "ladder" which was resistant to alkaline phosphatase but sensitive to RNases, indicating that it consisted of VP1 polypeptides with oligoribonucleotides of various lengths attached to them. Probing the ladder with 5' and 3' end-specific, as well as plus-, or minus-strand-specific oligonucleotides revealed that they represent VP1 linked to 5' terminal sequences of genome segment A- and B-specific plus strands. Pulse-chase experiments in combination with two-dimensional polyacrylamide gel electrophoresis revealed that labeled VP1 could be chased to replicative intermediate, to ssRNA, to dsRNA, and eventually to virion VPg-dsRNA and that VP1 could be released from all these structures by RNase treatment. We suggest that these results are most compatible with the model where a VP1-pN structure acts as a primer for viral RNA synthesis in vivo, a mechanism that has been shown to occur in vitro.
...
PMID:Conversion of VP1 to VPg in cells infected by infectious pancreatic necrosis virus. 961 75

Cytokine-driven activation of hepatic stellate cells (HSC) in tissue injury and inflammation is a key pathogenetic event in liver fibrogenesis leading to an expanded pool of matrix producing myofibroblasts (MFB) which represent the transformed counterpart of HSC. We hypothesize that expansion of the pool of MFB might also be accomplished by modulation of apoptosis, which plays an opposite and complementary role to mitosis in the cellular homeostasis. We characterized the susceptibility of HSC in primary culture and of MFB in secondary culture to apoptosis induced by the soluble Fas ligand (sFasL) and related the effects to the expression levels of Fas (APO-1/CD95) and some major proapoptotic and contra-apoptotic protooncogenes. MFB showed a dose-dependent apoptotic reaction upon exposure to sFasL as evidenced by a strong increase of nucleosomal DNA fragments, loss of cellular DNA, positive TUNEL reaction, and annexin staining. The effect was found only if protein synthesis (cycloheximide) or RNA synthesis (actinomycin D) were arrested. HSC maintained for various times in primary culture were completely resistant to sFasL in combination with cycloheximide, but in late primary cultures (day 7 onward) an increasing susceptibility to sFasL-mediated apoptosis was developed. By semiquantitative reverse-transcriptase polymerase chain reaction (RT-PCR) analysis and alkaline phosphatase-anti-alkaline phosphatase staining Fas receptor was identified both in HSC and MFB at comparable expression levels. The expression of the contra-apoptotic protooncogenes bcl-2 and bcl-xl was found to be much stronger in early HSC than in late HSC and MFB as shown by ribonuclease protection assay. The expression of bcl-2 was additionally confirmed by semiquantitative RT-PCR and immunoblotting. Proapoptotic bax was found in comparable quantities at the RNA level in HSC and MFB but at the protein level MFB showed increased bax expression. It is concluded that transformation of HSC to MFB is paralleled by an increasing sensitivity to sFasL-mediated apoptosis, which might be related to a strong decrease of bcl-2 and bcl-xl expression, leading to a preponderance of proapoptotic gene expression in MFB. Modulation of apoptotic susceptibility of transforming HSC could be an important complementary pathway in the pathogenesis of fibrosis.
...
PMID:Transformation-dependent susceptibility of rat hepatic stellate cells to apoptosis induced by soluble Fas ligand. 969 16

We investigated the relationship between the two forms of rabies virus P protein, a non-catalytic subunit of rabies virus RNA polymerase. The two displayed different electrophoretic mobilities as 37- and 40-kDa polypeptides, hence termed as p37 and p40, respectively. Double labeling experiments with [3H]leucine and [32P]orthophosphate demonstrated that p40 was much more phosphorylated than p37. Treatment of the virion proteins with alkaline phosphatase eliminated only p40, and not 37-kDa polypeptide. The p37 was a major product of the P gene, and was accumulated in the infected cell and incorporated into the virion. On the other hand, p40 was apparently detected only in the virion, and little detected in the cells. Treatment of infected cells with okadaic acid, however, resulted in significant accumulation of p40 in the cell, suggesting that p40 was continuously produced in the cell but dephosphorylated quickly. We detected both 37- and 40-kDa products in P cDNA-transfected animal cells, while only a 37-kDa product was produced in Escherichia coli. Incubation of 37-kDa products from E. coli with the lysates of animal cells in vitro resulted in the production of a 40-kDa product, which was also shown to be suppressed by the heparin. From these results, it is suggested that p40 is produced by the hyperphosphorylation of a 37-kDa polypeptide, which depends on certain heparin-sensitive cellular enzyme(s) and occurs even in the absence of the other viral gene products, and that p40 is reverted quickly to p37 in the infected cells, probably being dependent on some virus-induced factor(s).
...
PMID:Studies on the rabies virus RNA polymerase: 2. Possible relationships between the two forms of the non-catalytic subunit (P protein). 988 49

Simian virus 40 large T antigen is a multifunctional protein which has been shown to modulate the expression of genes transcribed by RNA polymerase I (Pol I), II, and III. In all three transcription systems, a key step in the activation process is the recruitment of large T antigen to the promoter by direct protein-protein interaction with the TATA binding protein (TBP)-TAF complexes, namely, SL1, TFIID, and TFIIIB. However, our previous studies on large T antigen stimulation of Pol I transcription also revealed that the binding to the TBP-TAFI complex SL1 is not sufficient to activate transcription. To further define the molecular mechanism involved in large T antigen-mediated Pol I activation, we examined whether the high-mobility group box-containing upstream binding factor (UBF) plays any role in this process. Here, using cell labeling experiments, we showed that large T antigen expression induces an increase in UBF phosphorylation. Further biochemical analysis demonstrated that UBF is phosphorylated by a kinase activity that is strongly associated with large T antigen, and that the carboxy-terminal activation domain of UBF is required for the phosphorylation to occur. Using in vitro reconstituted transcription assays, we demonstrated that the inability of alkaline phosphatase treated UBF to efficiently activate transcription can be rescued by large T antigen. Moreover, we showed that large T antigen-induced UBF phosphorylation promotes the formation of a stable UBF-SL1 complex. Together, these results provide strong evidence for an important role for the large T antigen-associated kinase in mediating the stimulation of RNA Pol I transcription.
...
PMID:A kinase activity associated with simian virus 40 large T antigen phosphorylates upstream binding factor (UBF) and promotes formation of a stable initiation complex between UBF and SL1. 1008 45


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

---