Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phospholipase C (PLC), which hydrolyzes phosphoinositides, has been implicated as a key enzyme in signal transduction. We examined the expression of an isozyme of PLC, PLC-delta, in rat colon neoplasms induced by methylazoxymethanol (MAM) acetate. Large-bowel neoplasms were observed in five of 10 rats given MAM acetate (25 mg/kg body weight, by interperitoneal injection at 6 and 7 wk of age) 40 wk after treatment. Expression of PLC-delta in the neoplasms was not detected by northern blot analysis, and a low level of expression was detected by immunoblot analysis, although PLC-delta expression was apparent in the non-neoplastic colon mucosae of MAM acetate-treated rats as well as in the colon mucosae of control rats. Furthermore, analysis by reverse transcriptase-polymerase chain reaction revealed that the ratio of the expression of PLC-delta to that of beta-actin in the neoplasms was significantly lower than the ratios in the non-neoplastic colon mucosae of carcinogen-treated and control rats (P < 0.01). However, the ornithine decarboxylase (ODC) activity in the neoplasms was significantly greater than that of the non-neoplastic and control mucosae (P < 0.001). The differences in the levels of PLC-delta expression in neoplastic and non-neoplastic tissues and the inverse correlation of PLC-delta expression with ODC activity may suggest that PLC-delta has little effect on the PLC-mediated mitogenic signaling system, at least in MAM acetate-induced colon neoplasms in rats.
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PMID:Reduced expression of phospholipase C-delta, a signal-transducing enzyme, in rat colon neoplasms induced by methylazoxymethanol acetate. 752 22

HIV-1 reverse transcriptase is a dimeric enzyme mainly involved in the replication of the viral genome. A filamentous phage cDNA expression library from human lymphocytes was used to select cellular proteins interacting with HIV-1 reverse transcriptase Affinity selections using the bacterially expressed monomeric large subunit of reverse transcriptase (p66) yielded host beta-actin. This clone was expressed as glutathione-S-transferase fusion protein which was identified by using a specific antibody against beta-actin. Furthermore we show that also the eukaryotic beta-actin binds to either the large subunit of reverse transcriptase or to the Pol precursor polyprotein in vitro. The reverse transcriptase/beta-actin interaction might be important for the secretion of HIV-1 virions.
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PMID:The large subunit of HIV-1 reverse transcriptase interacts with beta-actin. 753 22

Little is known about the molecular mechanisms governing the development of human oocyte and pre-embryo. We characterized the expression pattern of c-mos, cyclin B1 and beta-actin mRNA in oocytes and granulosa cells from human and monkey, and in human early embryos, using both qualitative and semi-quantitative reverse transcriptase polymerase chain reaction. The proto-oncogene c-mos was expressed in an oocyte-specific manner and no mRNA for c-mos could be detected in the granulosa cells. Similarly, strong expression of cyclin-B1 was seen in the oocytes. In human pre-embryos, the expression of cyclin-B1 and beta-actin increased from the 6-cell stage onwards, indicating active transcription and thus activation of embryonic genome either at or before the 6-cell stage. The expression of c-mos was transient and very little c-mos mRNA could be detected in the human embryos beyond the 6-cell stage. Thus, both its time-specific and site-specific expression suggest meiosis-specific functions for the proto-oncogene c-mos in human oocytes. As judged by the disappearance of c-mos, the maternal pool of mRNA seems to be degraded towards the 6- to 8-cell stage. The transient expression of c-mos and high levels of cyclin-B1 mRNA suggest that mechanisms similar to those found in lower organisms govern the growth and development of the human oocyte and preimplantation embryo.
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PMID:Cell cycle genes c-mos and cyclin-B1 are expressed in a specific pattern in human oocytes and preimplantation embryos. 754 Jan 81

We describe here the development, optimization, and use of a non-radioactive, quantitative, multiplex reverse transcriptase-PCR technique to measure, in a single reaction, the relative levels of the transcripts of four DNA repair genes (XPCC, hMSH2, XRCC1, and ERCC1) and the beta-actin gene in lymphoblastoid cell lines and frozen peripheral blood lymphocytes. Expression of defective DNA repair genes was not detected in DNA repair-deficient human cell lines, whereas the intact genes were detected in repair-proficient cell lines and in lymphocytes from a normal donor. The assay was reproducible, and repeated determinations of the same samples generated highly consistent results for each target gene. This approach should facilitate molecular epidemiological studies that incorporate screening for germline alterations that may affect gene expression and for changes in the levels of gene expression.
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PMID:Simultaneous amplification of four DNA repair genes and beta-actin in human lymphocytes by multiplex reverse transcriptase-PCR. 758 46

Human papillomavirus type 11 (HPV-11), produced from the athymic mouse xenograft system, was shown to infect cultured neonatal human foreskin keratinocytes and the HaCaT keratinocyte cell line in vitro. Infection was documented by the appearance of HPV-11-specific spliced mRNA, detected by reverse transcriptase-polymerase chain reaction. Purified HPV-11 virions at concentrations of approximately 10(7) particles/ml could successfully evoke infection in this system. Infection was completely abrogated by preincubation of the HPV-11 inoculum with mouse anti-HPV-11 monoclonal antibodies, experimentally immunized animal sera, or sera of human patients with HPV infection. Concurrent detection of cellular mRNA for the beta-actin gene, also by reverse transcriptase-polymerase chain reaction, provided an internal control confirming RNA recovery and successful reverse transcriptase-polymerase chain reaction. Using this approach, it was possible to determine semiquantitative titers for test solutions of HPV-11-neutralizing antibodies. The in vitro system for HPV-11 infectivity and neutralization may be useful in the study of the immune response to HPV-11 infection or immunization in patients.
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PMID:Titration of HPV-11 infectivity and antibody neutralization can be measured in vitro. 766 26

Recent studies have shown that two different voltage-dependent Ca2+ channels are expressed in pancreatic islets, the beta-cell/neuroendocrine-brain and the cardiac subtypes. The effects of chronic hyperglycemia on the levels in pancreatic islets of the mRNAs encoding the alpha 1-subunits of the beta-cell and cardiac subtype Ca2+ channels were studied in rats made hyperglycemic by infusion of glucose for 48 h. A competitive reverse transcriptase-polymerase chain reaction procedure was used to obtain quantitative data on the levels of these two transcripts in islets obtained from individual rats. The quantitative polymerase chain reaction data indicate that the levels of mRNA encoding the alpha 1-subunit of the beta-cell Ca2+ channel are 2.5-fold greater than those for the cardiac subtype. The levels of beta-cell Ca2+ channel mRNA were 72.9% lower in the glucose-infused animals when compared with the saline-infused animals (P < 0.005) and those of the cardiac channel were 72.1% lower in the animals infused with glucose (P < 0.02). In contrast, glucose infusion resulted in a twofold increase in insulin mRNA levels and did not significantly alter levels of beta-actin mRNA. In situ hybridization studies revealed that the mRNAs for these two Ca2+ channels are expressed at higher levels in normal rat islets than in the surrounding acinar tissue, which suggests that the observed changes in mRNA levels occur within cells of the pancreatic islet. To assess the possible functional consequences of this reduction in expression of mRNA for the Ca2+ channels, the insulin secretory responses of perfused pancreases to the Ca2+ channel agonist Bay K8644 were studied.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression of calcium channel mRNAs in rat pancreatic islets and downregulation after glucose infusion. 768 20

Perforin and granzyme B are 2 cytolytic proteins specific to activated killer cells, particularly CTL. We have studied the mRNA expression of these 2 proteins by a reverse transcriptase polymerase chain reaction method in a unidirectional model of rat small intestine transplant rejection. The allograft group consisted of Lewis x Brown Norway F1 donors into Lewis recipients. The isograft controls were Lewis donors into Lewis recipients. Grafts were placed heterotopically and no immunosuppression was given. Five animals in each group were killed at postoperative days (POD) 3, 5, 7, 8, 9, 10, 12, and 14. mRNA was extracted and a semiquantitative reverse transcriptase polymerase chain reaction was performed. For the semiquantitative analysis, we compared scintillation counts from excised bands. Results were expressed as a percent activity compared with beta-actin. From the same tissue samples, a histologic evaluation was made and rejection was graded according to severity. The isograft controls showed no evidence of histologic rejection and a very low expression of mRNA for perforin and granzyme B from POD 3-14. In contrast, the allograft group began to show histologic evidence of mild rejection on POD 5. By day 7, rejection was moderately severe and associated with a significant up-regulation of perforin and granzyme B in the allografts compared with the controls (P < 0.01), which persisted through POD 14. Peak expression for perforin and granzyme B was on POD 10 and 8, respectively. We conclude that the up-regulation of perforin and granzyme B in rat small intestine transplant allografts is a useful marker of clinically important rejection.
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PMID:Perforin and granzyme B. Cytolytic proteins up-regulated during rejection of rat small intestine allografts. 788 5

We have developed a method to monitor mRNA expression that is based upon the reverse transcriptase-polymerase chain reaction (RT-PCR) and includes multiple sets of primer pairs in coamplification reactions. To observe relative changes in mRNA steady-state levels, each target in a multiplex reaction was amplified to within a predetermined range by using PCR cycle numbers specific for each target. Optimal PCR cycle numbers for target templates were determined by preliminary titration experiments performed using the "primer-dropping" method. By employing this method, the overall amplification reaction was limited, permitting the PCR products to remain within the exponential range of the amplification curve and yet be detectable on ethidium bromide-stained gels. We demonstrated the utility of this method by monitoring the expression kinetics of cyclins A, B1, D1, and E, and of the immediate-early genes c-fos, c-myc, and beta-actin. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was included in the multiplex reactions as an endogenous internal standard to control for variations in product abundances due to differences in individual RT and PCR reaction efficiencies. Changes in gene expression of less than twofold to greater than 75-fold were readily distinguished.
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PMID:Monitoring mRNA expression by polymerase chain reaction: the "primer-dropping" method. 788 71

Rejection continues to be a major cause of graft loss in small intestine transplantation (SIT). We have studied, by semiquantitative reverse transcriptase PCR (rtPCR), the intragraft expression of cytokines relevant to rejection in a rat model. Heterotopic SIT grafts were performed from Lewis x Brown Norway F1 donors into Lewis recipients. The isograft control was Lewis into Lewis. Five animals in each isograft and allograft group were sacrificed on POD 3, 5, 7, 8, 9, 10, 12, and 14. mRNA was isolated from portions of the terminal ileum and rtPCR performed to amplify message for interleukin-2 (IL-2), IL-2 receptor (IL-2R), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma). Semiquantitative analysis was performed using 32P radionuclide incorporation and scintillation counting. The results were expressed as percent activity compared with beta-actin. Histologic correlation with cytokine expression was made. On POD 3 after SIT there was no evidence of rejection by histology and all cytokines studied showed no difference between the isograft and the allograft. On POD 5 the first evidence of mild rejection was seen on histology and IL-6, IFN-gamma, TNF-alpha showed a significant up regulation in the allograft that persisted through POD 14. mRNA for IL-2 was not significantly upregulated until POD 7 and persisted until POD 14. IL-2R was constitutively expressed in both isograft and allograft and was not a reliable predictor of rejection. Histologic rejection was moderately severe by POD 7 and severe between POD 8 and 14 correlating with the increasing expression of IL-6, IFN-gamma, and TNF-alpha. In summary, we have shown that increasing expression of mRNA for IL-6, IFN-gamma, and TNF-alpha not only correlated with severity of rejection but that upregulation began early when histologic evidence of rejection first occurred.
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PMID:The correlation of intragraft cytokine expression with rejection in rat small intestine transplantation. 794 Jun 88

We determined T-cell cytokine profiles in the epidermis, dermis, and blood of cutaneous T-cell lymphoma to differentiate whether unique cytokine profiles were associated with mycosis fungoides (MF) versus Sezary syndrome. Punch biopsy specimens from plaque stage MF (n = 7) were compared to Sezary skin (n = 3) after undergoing rapid heat-saline separation of epidermis from dermis. Normal adult skin (n = 11), neonatal foreskin (n = 4), untreated psoriatic plaques (n = 6), and normal donor peripheral blood leukocytes (n = 3) were studied as controls. Total RNA was extracted from all skin specimens, as well as peripheral blood leukocytes from MF (n = 3) and Sezary patients (n = 7), and was converted to cDNA by reverse transcriptase. Polymerase chain reaction amplification of cDNAs using interleukin 2 (IL-2), IL-4, IL-5, IL-10, and interferon gamma-specific primers was used to differentiate Th1-type responses (IL-2+ and interferon gamma +) from Th2-type responses (IL-4+, IL-5+, and IL-10+). beta-actin specific primers were included as a positive control for mRNA integrity. All MF specimens contained mRNAs for IL-2 and interferon gamma limited to epidermis but not IL-4, IL-5, or IL-10. In contrast, Sezary skin and blood showed a cytokine mRNA pattern dominated by IL-4, IL-5, and IL-10. MF blood showed a pattern similar to normal peripheral blood T cells with mixed detection of all T-helper cell cytokine mRNAs. All psoriasis samples contained mRNAs for IL-2 and interferon gamma in both epidermis and dermis with no IL-4 or IL-10 in either compartment. These findings demonstrate that the cutaneous lesions of MF are characterized by an epidermal Th1-type cytokine profile, whereas both the blood and skin of patients with Sezary syndrome is characterized by a Th2-type profile. This work suggests that differences in cytokine production may be related to the pathophysiology and clinical presentation in cutaneous T-cell lymphoma.
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PMID:Mycosis fungoides exhibits a Th1-type cell-mediated cytokine profile whereas Sezary syndrome expresses a Th2-type profile. 749 Apr 83


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