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)

EBNA 1 is the only antigen expressed in both Epstein-Barr virus (EBV)-infected nasopharyngeal carcinoma (NPC) and Burkitt's lymphoma cells. Previous studies showed that the mRNA of EBNA 1 in these two tumor tissues was initiated from a promoter located in the Bam HI F fragment (Fp) on the viral genome. Two regulatory elements located in the downstream Bam HI Q region include an EBNA 1 binding site and a positive regulatory region between the Fp and the EBNA1 binding site. This data strongly suggested that a cellular factor(s) may modulate the usage of the Fp. To locate the shortest responsible viral sequence, we constructed a series of luciferase gene and chloramphenicol acetyltransferase (CAT) gene plasmids that contained various portions of the Bam HI F/Q region. Plasmid DNA was then introduced into cells to examine the promoter activity of each construct. By this method, we identified a 186-bp fragment within the Bam HI Q region that possessed the highest activity. This promoter was designated as Qp and found to be orientation-dependent and down-regulated by EBNA 1 in both the type I BL cells and human epithelial cells. Furthermore, RNase protection assay showed that a transcription initiation site was located at nucleotide 62,416 of the EBV genome. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis further confirmed that the transcript was initiated from the Qp, and not the Fp. Therefore, our data suggested that a novel promoter, Qp, located within the Bam HI Q existed for the EBNA 1 expression in the latently infected type 1 BL cells. The biological significance of the selection of the Qp needs further investigation.
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PMID:Identification of a novel promoter located within the Bam HI Q region of the Epstein-Barr virus genome for the EBNA 1 gene. 766 54

Reverse transcriptase (RT)-PCR with primers specific for surfactant protein A (SP-A), B (SP-B), C (SP-C), and D (SP-D) genes was applied to detect metastatic non-small cell lung carcinomas. Forty-one paratracheal and subcarinal lymph nodes obtained from 41 patients with non-small cell lung carcinomas, 11 lymph nodes from 11 patients with extrapulmonary adenocarcinomas, and eight control lymph nodes from patients without cancer were analyzed using RT-PCR. PCR products corresponding to SP-B gene products were found in all eight control lymph nodes, offering evidence of SP-B gene expression in cells of lymphatic tissue. SP-A, SP-C, and/or SP-D transcripts were detected in 11 (84.6%) of 13 lymph nodes with histologically identifiable metastases of pulmonary adenocarcinomas and in 10 (55.5%) of 18 lymph nodes that were tumor free on routine histological examination. These findings provide evidence of micrometastatic nodal involvement which remains undetectable by conventional light microscopy but can be evaluated by surfactant RT-PCR. Gene expression of SP-A and SP-C was restricted to metastatic pulmonary adenocarcinomas but SP-D gene activity has been also detected in two of four metastases of pulmonary large cell carcinomas, one adenosquamous carcinoma, and nine extrapulmonary adenocarcinomas as well.
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PMID:Surfactant protein gene expression in metastatic and micrometastatic pulmonary adenocarcinomas and other non-small cell lung carcinomas: detection by reverse transcriptase-polymerase chain reaction. 767 Dec 36

It is currently under debate whether the low serum cholesterol levels that are frequently observed in cancer patients represent a risk factor for/or, rather, are a consequence of the tumour. We postulate that malignant tumours are directly involved in an increased catabolism of cholesterol-rich low-density lipoprotein (LDL) particles. In a prospective study of 25 patients with colorectal carcinoma, we measured intraindividual shifts in serum cholesterol levels after surgery, and the expression of LDL-receptor mRNA in surgically removed specimens. A significant rise in plasma cholesterol levels was observed in patients 3 and 12 months after curative surgery, but not after non-curative surgery. In human colon carcinoma tissues LDL receptor mRNA expression, as determined by competitive reverse-transcriptase-polymerase-chain reaction, was found to be significantly increased when compared to tissues from the tumour-free margin (median values, 1.2 x 10(6) vs. 2.0 x 10(5) molecules/micrograms total cellular RNA, respectively, n = 17). The extent of LDL-receptor mRNA expression positively correlated to the percentage rise of plasma cholesterol levels 3 months (n = 7, r = 0.8763) and 12 months (n = 6, r = 0.9181) after curative surgery. This finding provides in vivo evidence that the tumour tissue itself contributes to decreased plasma cholesterol levels in patients suffering from colorectal carcinomas. It supports the hypothesis that low cholesterol levels in cancer patients are a consequence, and not the cause, of the malignancy.
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PMID:Increased LDL receptor mRNA expression in colon cancer is correlated with a rise in plasma cholesterol levels after curative surgery. 775 50

Trypsin inhibitors in serum-free conditioned media (SFCM) of various human carcinoma cell lines were analyzed by reverse zymography. Most of the cells secreted high-molecular-weight trypsin inhibitors (HMTI) larger than 100 kDa. The cell lines of colorectal carcinoma origin had a tendency to secrete HMTI whose molecular weight was a little higher than that of the other cell lines. Analysis of SFCM of subclones with different histological differentiation and metastatic/invasive potentials derived from a single pancreatic carcinoma cell line SUIT-2 showed that the HMTI activity in SFCM was correlated to the degree of histological differentiation in vivo and tended to be inversely correlated to their metastatic/invasive capabilities. Immunoblotting analysis revealed that these HMTI were protease nexin-II/amyloid beta protein precursors (PN-II/APP). Semi-quantificative reverse-transcriptase/polymerase-chain reaction study for PN-II/APP mRNAs suggested that the differences in PN-II/APP activities in SFCM between the subclones might be post-transcriptional or post-secretional events. In addition, SFCM of a highly metastatic subclone contained 43-kDa protein which reacted to anti-APP monoclonal antibody (MAb) suggesting that the subclone may have APP-degrading activity.
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PMID:Reverse-zymographic analysis of protease nexin-II/amyloid beta protein precursor of human carcinoma cell lines, with special reference to the grade of differentiation and metastatic phenotype. 781 44

The plasminogen (Plg) system on rat yolk sac carcinoma (L2) cells was characterized by zymography, Western and immunoprecipitation analysis, reverse-transcriptase polymerase chain reaction, binding, and activity assays. The L2 cells produced tissue Plg activator but not urokinase Plg activator and contained RNA for Plg activator inhibitor 1, but Plg activator inhibitor 1 was not detectable by zymography or Western analysis and contained the receptor for urokinase Plg activator. Plg bound to the cells in a saturable manner when plasmin inhibitors were present with a dissociation constant of 1.34 +/- 0.18 x 10(-6) M and 1.54 +/- 0.25 x 10(7) sites/cell. Immunoprecipitation analysis showed that Plg was binding to gp330, a known Plg receptor. Once bound to the L2 cells, Plg was activated by tissue Plg activator to plasmin in a time- and concentration-dependent manner. Under saturating Plg conditions, most of the plasmin produced was released into the medium. Inhibition of plasmin activation occurred when Plg activator inhibitor 1, anticatalytic tissue Plg activator antibody, or Heymann nephritis autoantibody was present.
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PMID:Characterization of plasminogen system on rat yolk sac carcinoma (L2) cells. 786 83

We sought to determine whether the hepatocyte growth factor/scatter factor (HGF/SF)- and keratinocyte growth factor-receptor systems were expressed in normal breast cells, breast carcinoma cell lines, normal breast tissues, and breast cancer tissues. Reverse transcriptase-polymerase chain reaction and hot blotting were used to detect HGF, HGF/SF (met) receptor, KGF, and KGF receptor mRNAs in human mammary epithelial (HME) and stromal (HMS) cells. We also examined breast carcinoma (MDA-MB-157, SCC 38, and SCC 70) and spontaneously immortalized breast epithelial (HMT 3522) cell lines, as well as normal breast and breast carcinoma tissues. PCR products were also confirmed by nucleic acid sequencing. The effects of HGF and KGF, compared to EGF and heparin-binding EGF, on the proliferation of normal human mammary epithelial cells in serum-free defined medium was determined by cell counting. HGF and KGF mRNAs were detected in HMS cells, but not HME cells. KGF receptor mRNA was detected in HME cells, but not HMS cells. HGF/SF receptor mRNA was detected in both HME and HMS cells. mRNAs were also detected in normal breast and breast carcinoma tissues, as well as breast carcinoma and transformed breast epithelial cell lines. Alternative cDNA sequences that are predicted to code for a soluble KGF receptor and a membrane bound, truncated HGF/SF receptor were detected in breast epithelial cells and breast tissues. HGF and KGF maintained viability and stimulated proliferation of HME cells.
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PMID:Hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), and their receptors in human breast cells and tissues: alternative receptors. 786 34

Transcription and replication are, like many other nuclear functions and components, concentrated in nuclear domains. Transcription domains and replication domains may play an important role in the coordination of gene expression and gene duplication in S-phase. We have investigated the spatial relationship between transcription and replication in S-phase nuclei after fluorescent labelling of nascent RNA and nascent DNA, using confocal immunofluorescence microscopy. Permeabilized human bladder carcinoma cells were labelled with 5-bromouridine 5'-triphosphate and digoxigenin-11-deoxyuridine 5'-triphosphate to visualize sites of RNA synthesis and DNA synthesis, respectively. Transcription by RNA polymerase II was localized in several hundreds of domains scattered throughout the nucleoplasm in all stages of S-phase. This distribution resembled that of nascent DNA in early S-phase. In contrast, replication patterns in late S-phase consisted of fewer, larger replication domains. In double-labelling experiments we found that transcription domains did not colocalize with replication domains in late S-phase nuclei. This is in agreement with the notion that late replicating DNA is generally not actively transcribed. Also in early S-phase nuclei, transcription domains and replication domains did not colocalize. We conclude that nuclear domains exist, large enough to be resolved by light microscopy, that are characterized by a high activity of either transcription or replication, but never both at the same time. This probably means that as soon as the DNA in a nuclear domain is being replicated, transcription of that DNA essentially stops until replication in the entire domain is completed.
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PMID:RNA polymerase II transcription is concentrated outside replication domains throughout S-phase. 796 88

Within the hematopoietic lineage, the monoclonal antibody (MoAb) CD66 reacts with cells of the granulocyte lineage, but not with the majority of progenitor cells from human bone marrow. Our previous studies have shown that CD66 binds specifically to at least three carcinoembryonic antigen (CEA) superfamily members, ie, CEA itself, nonspecific cross-reacting antigen (NCA), and CGM1, but not to CGM6 (NCA-95). In this report, we show that CD66 will also identify the biliary glycoproteins (BGP). A full-length cDNA for the BGPc molecule (a cytoplasmic splice variant of BGPa) was isolated by expression cloning using the CD66 MoAbs. This protein has an identical extracellular and transmembrane sequence to BGPa with one N-terminal IgV like domain, three IgC-like extracellular domains (A1, B1, and A2), plus a transmembrane domain, but the cytoplasmic domain is spliced by 53 nucleotides. Reverse transcriptase-polymerase chain reaction experiments show that this splice variant can be detected in colonic carcinoma cell lines, in primary colonic adenocarcinomas, and in myeloid and B-cell lines to varying degrees. Quantitative analyses of BGPc RNA expression by RNase protection indicate that abundant levels occur only in the colonic, but not in the hematopoietic, cell lines tested. Studies presented here show that BGPc mediates homotypic adhesion and suggest that the cytoplasmic splicing does not alter the initial homotypic adhesion properties of BGPa.
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PMID:CD66 identifies the biliary glycoprotein (BGP) adhesion molecule: cloning, expression, and adhesion functions of the BGPc splice variant. 801 19

A novel immunomodulator, imiquimod, has been shown to be an effective topical antiviral and antitumor agent in animal models. Imiquimod has been reported to induce interferon-alpha and other cytokines in animals and humans, but its precise role as an immunomodulator at skin sites has not been determined. We investigated its effect on cytokine gene expression in the human epidermal carcinoma cell line COLO-16 and human keratinocytes. COLO-16 cells were incubated with imiquimod (1 and 10 micrograms/ml) and human keratinocytes with 5 micrograms/ml for 6 or 24 h. Cytokine gene expression was analyzed by reverse-transcriptase PCR. In COLO-16 cells, imiquimod stimulated IL-6 mRNA levels 2.3- and 4.4-fold at 1 and 10 micrograms/ml after 6 h. IL-8 mRNA increased 4-fold at both 1 and 10 micrograms/ml. At 24 h, though IL-6 mRNA level at 1 micrograms/ml was further stimulated, enhanced expressions of IL-8 at 1 micrograms/ml and both IL-6 and IL-8 at 10 micrograms/ml were down-regulated. In human keratinocytes, 5 micrograms/ml of imiquimod stimulated IL-6 mRNA levels 1.4-fold at 6 h and 2.1-fold at 24 h, and IL-8 mRNA levels 1.7- and 2.0-fold at 6 and 24 h. IL-1 alpha mRNA levels in COLO-16 or keratinocytes were unchanged by either dose or incubation time. These results suggest that stimulation of IL-6 and IL-8 expression may be involved in the immunomodulating action of imiquimod.
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PMID:Effects of a novel topical immunomodulator, imiquimod, on keratinocyte cytokine gene expression. 806 Nov 17

The possibility that dietary intake of diverse naturally occurring compounds may influence the occurrence of cancer is receiving considerable scientific attention. Previously, it was reported that an extract (Crocus sativus), which contains carotenoids, had an antitumor effect and inhibited colony formation and nucleic acid synthesis by malignant human cells. Epidemiological and experimental research has indicated that carotenoids might act as antitumor agents. We have studied crocetin, a carotenoid isolated from saffron, which has been shown to have biological activity. In our experiments we utilized three malignant human cell lines: HeLa (cervical epitheloid carcinoma), A549 (lung adenocarcinoma) and VA13 (SV-40 transformed fetal lung fibroblast) cells. The effect of crocetin on colony formation and cellular DNA, RNA and protein synthesis in these cells has been examined. Incubation of these cells with crocetin for 3 h caused a dose-dependent inhibition of nucleic acid and protein synthesis. Crocetin also had a dose-dependent inhibitory effect on DNA and RNA synthesis in isolated nuclei and suppressed the activity of purified RNA polymerase II.
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PMID:Inhibitory effect of crocetin on intracellular nucleic acid and protein synthesis in malignant cells. 829 27


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