Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lymphoid cells were purified from the spleens of 15 woodchucks and examined for the presence of woodchuck hepatitis virus (WHV). Lymphoid cells from the spleens of eight of eight chronically infected animals contained high levels of WHV RNA and DNA. A 100-fold lower level of WHV DNA was found in the spleen from one of five animals that had recovered from acute WHV infections 2 years before this analysis. No WHV nucleic acids were observed in either of two uninfected animals. WHV DNA patterns in the lymphoid cells from the spleens of the chronically infected animals, which included the presence of single-stranded DNA and RNA-DNA hybrid molecules, were identical to those observed in WHV-infected liver. WHV DNA in these cells was present in intact, 27-nm core particles which also contained the endogenous DNA polymerase activity. These results indicate that the spleen is a site of active WHV DNA replication and is most likely a major source of WHV-infected cells in the circulating lymphoid cell population.
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PMID:Lymphoid cells in the spleens of woodchuck hepatitis virus-infected woodchucks are a site of active viral replication. 357 41

Measurement of the activity of the enzyme DNA polymerase alpha has been investigated with regard to its potential usefulness as a method for the detection and quantification of lymphocyte activation in vivo. A modified enzyme assay was developed in order to optimise measurement of activity in crude homogenates of cells or tissues, thus allowing the convenient handling of multiple samples. Specificity of the assay for polymerase alpha was ensured by the inclusion in the assay mixture of dideoxythymidine triphosphate, an inhibitor of the other eukaryotic DNA polymerases. The activity of DNA polymerase alpha was found to be closely correlated with [3H]thymidine incorporation in a mitogen-stimulated in vitro system. The usefulness of the polymerase alpha method for the quantification of lymphocyte activation was validated in 3 different in vivo systems of either immune-mediated or drug-induced lymphoid cell response.
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PMID:Quantification of lymphocyte activation by measurement of DNA polymerase alpha activity. 393 83

Herpes simplex virus was grown in a 6-liter suspended culture of an atypical permanent human lymphoid cell line, Roswell Park Memorial Institute no. 8226. The kinetics of virus replication were determined by counting viruses by electron microscopy, plaque formation, and tissue culture infectivity. Deoxyribonucleic acid-dependent deoxyribonucleic acid polymerase activity was determined during the course of infection. Electron microscopy studies substantiated the kinetics of the virus infection in lymphoid cells.
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PMID:Characterization of the growth of herpes simplex virus in human lymphoid cells. 411 Apr 23

Treatment of lymphoid 594S/F9 cells with 12-o-tetradecanoylphorbol-13-acetate (TPA), cycloheximide (CH) has no effect on cell proliferation. A reversible blocking of the cellular DNA and RNA synthesis is observed. Repeated treatment with TPA, iododeoxyuridine (IDU) or sodium butyrate (SB) causes more pronounced changes in cell metabolism, which sharply decreases the salt sensitive DNA polymerase activity. Simultaneously the activity of the virus-induced ammonium sulphate resistant DNA polymerase increases. The combined effect of TPA and CH stimulates the synthesis of viral antigens in certain latently infected cells. The number of productively infected cells remains approximately at the same level for 96 h. IDU has a highest effect on viral antigens expression at repeated induction.
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PMID:[Induction of baboon herpes virus antigens in producing lymphoblastoid cells]. 621 Jan 92

The ubiquitous trace metal zinc has been discovered since a long time as an intrinsic element in all biological systems. However, its role other than structural or catalytic in enzymes is poorly defined. Zinc plays a determinative role both in primary and secondary T lymphocyte production. Experimental data support the notion that during intrathymic maturation, non-autoreactive, immunocompetent T cell clones are selected from the excess of immature thymocytes as a result of expansion of bone marrow derived prothymocytes in response to pleiotropically acting alarmon (s) and a subsequent escape via the thymic stroma cells from nucleotide-mediated "biochemical suicide". The activity of alarmon (Ap4A), nucleotide metabolizing enzymes (TdT, DNA polymerase, thymidine kinase, 5'-nucleotidase) and some of the soluble stromal cell products (FTS) require constitutive zinc. In the peripheral lymphoid organs the magnitude and duration of antigen induced, T cell mediated immunoreactions are regulated by T-cell growth factor (IL-2). Using receptor specific monoclonal antibody probes, it has been established recently that the intracellular role of IL-2 is probably to induce the phenotypic expression of high affinity transferrin receptors, known to be the main zinc transporter system in T-lymphocytes. The coordinative role of zinc in T lymphocyte development via the inducible metallothionein system is emphasized. Some clinical aspects of zinc metabolism are discussed.
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PMID:Zinc and immunity. 623 34

We have investigated the induction of Fc receptor (FcR) in different types of lymphoid cell lines (LCL) infected with herpes simplex virus (HSV). Subpopulations of certain of these LCL normally express FcR unrelated to herpetic infection. Differentiation of virus-induced FcR from that related to normal cell function was therefore possible. FcR detection was carried out by means of a rosette assay using ox erythrocytes coated with 7S immunoglobulin G (EA rosettes). Both HSV types 1 and 2 were found to induce FcR in B, T, and "null" (i.e., non-B, non-T) type LCL; however, in all the LCL tested, this HSV-induced FcR expression appeared to be more restricted in the responding T LCL than in responding B and null type LCL. In addition, kinetic experiments revealed that the time course of HSV-induced FcR expression differed among these LCL types tested. Interestingly, a number of LCL were resistant to HSV infection or restricted HSV gene expression, including expression of the viral products responsible for FcR induction. In all the responding HSV-infected LCL, induction of FcR always paralleled the expression of HSV antigens. Synthesis of HSV-induced FcR was shown to be inhibited by phosphonoacetic acid, an inhibitor of herpesvirus DNA polymerase activity, whereas FcR of non-HSV origin was found to be resistant to inhibitor. This would infer that HSV codes for an FcR which can be differentiated from that of cellular origin by using phosphonoacetic acid. Therefore, two different mechanisms of FcR synthesis may be suggested, one virus mediated and the second probably under cellular control. In addition, the data obtained using Epstein-Barr virus producer as well as isogeneic monoclonal cell lines, with and without the Epstein-Barr virus genome, indicated that the resident Epstein-Barr virus genome in the target cell did not have a detectable effect in the induction of FcR by HSV.
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PMID:Herpesvirus-lymphoid cell interactions: comparative studies on the biology of herpes simplex virus-induced Fc receptors in B, T, and "null" lymphoid cell lines. 624 24

1-beta-D-Arabinofuranosylthymine (araT) is a selective inhibitor of Epstein-Barr virus replication induced in both thymidine kinase (TK)-negative (TK-) and TK+ variants of the lymphoid cell line P3HR-I. This analog has no effect on the growth of noninduced cells (T. Ooka and A. Calender, Virology 104:219-223, 1980). The synthesis of early antigens is not affected by the analog, whereas that of late viral capsid antigens is completely inhibited, as demonstrated by the indirect immunofluorescence technique; kinetic reassociation experiments have also shown that araT strongly inhibits replication of viral DNA. Phosphorylation of the tritiated form of the analog ([3H]araT) was analyzed by thin-layer chromatography in cultures of control and induced cells, and the results demonstrated that only induced cells can convert the analog to the triphosphate form. These results indicate that the selective effect of araT in induced cells is probably related to a new virally induced TK activity. Preliminary characterization of this new activity has shown that it is able to phosphorylate the analog specifically, whereas cellular TKs cannot. araTTP, a final phosphorylation product of araT, is a potent inhibitor of Epstein-Barr virus-specific DNA polymerase, suggesting a possible inhibitory action of this product on Epstein-Barr virus replication.
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PMID:Effect of arabinofuranosylthymine on the replication of Epstein-Barr virus and relationship with a new induced thymidine kinase activity. 629 56

The incorporation of ATP on poly(A) primers catalyzed by poly(A) polymerase was investigated in normal and neoplastic lymphoid cells from animal and human sources. High levels of the enzyme were found in mouse thymus, in chicken bursa and thymus, as well as in neoplastic cells from patients affected by lymphoblastic and Burkitt's lymphomas. Low or very low quantities were found in peripheral blood lymphocytes, chronic lymphocytic leukemia cells, normal lymph nodes and solid lymphoid tissues of Hodgkin's disease. In general, the enzymatic content of neoplastic lymphoid cells reflected those of their normal counterpart. No effect of fasting or cortisone treatment on poly(A) polymerase in mouse spleen, thymus or liver was found. No particular relationships with B, T or non-T, non-B lineages were observed, but some relationship with DNA polymerase alpha was found. Therefore, it may be that poly(A) polymerase levels are related to the proliferative activity of the cellular populations.
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PMID:Poly(A) polymerase distribution in normal and malignant lymphoid cells. 632 15

The activities of 5-methyltetrahydrofolate (5-CH3-THF)-related enzymes [5-CH3-THF homocysteine methyltransferase and 5,10-methylenetetrahydrofolate (5,10-CH2-THF) reductase] and DNA polymerase alpha were measured in normal and malignant hematopoietic cells. The 5-CH3-THF homocysteine methyltransferase activity was significantly correlated with 5,10-CH2-THF reductase activity, indicating that the hematopoietic cells with active biosynthesis of tetrahydrofolate from 5-CH3-THF also actively synthesize 5-CH3-THF from 5,10-CH2-THF. The activities of 5-CH3-THF-related enzymes had a tendency to be high in lymphoid cells and low in myeloid cells, and were not correlated with the percentage of blasts and immature cells in the samples examined. Fairly good correlations were observed among these three enzymes in non-malignant bone marrow cells. However, the activities of two of the enzymes correlated only weakly overall with DNA polymerase alpha activity in normal and malignant hematopoietic cells. Generally speaking, DNA polymerase alpha activity correlated well with the percentage of blasts and immature cells in the samples examined.
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PMID:5-methyltetrahydrofolate-related enzymes and DNA polymerase alpha in normal and malignant hematopoietic cells. 635 15

Enzyme activity measurements are of great relevance to the classification and biochemical characterization of the various types of leukemias, but they have been much less studied in solid lymphoid tumors. The authors report investigations in human lymphomas. The levels of the following enzymes were determined: terminal deoxynucleotidyl transferase (TdT), deoxyribonucleic acid polymerase alpha (DP alpha), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), thymidine and uridine kinases (TK and UK, respectively), and thymidine phosphorylase (ThPh). Moreover, cytochemical investigations were done in the group of Burkitt's lymphoma (BL) and lymphoblastic lymphoma (LL), and ultrastructural studies were performed in seven of the nine LL of this series. These results were obtained: (1) TdT (90 cases) was highly specific for LL; eight of nine LL were positive, and all other histologic types were negative; the only TdT-, acid esterase (AcE) positive, nonconvoluted LL was probably related to TdT- normal medullary thymocytes, and had an unfavorable clinical course with resistance to a vincristine-and-prednisone-including treatment; (2) ADA (61 cases) could distinguish clearly between the high levels of LL and the low levels found in any other group of lymphomas; among LL, the highest values were found in T-cell-derived neoplasias, and the lowest value in a periodic acid-Schiff (PAS) positive, acid phosphatase negative case that showed the presence of large nucleoli at the ultrastructural analysis, a finding that is unusual for LL and possibly related to a more immature differentiation stage; (3) PNP (39 cases) values alone were not clinically relevant, but together with ADA levels, a subset of T-LL with high ADA:PNP ratio could be selected among LL; (4) DP alpha (61 cases), and TK and UK (37 cases) were found in concentrations reflecting the malignancy of the non-Hodgkin's lymphoma, and were more elevated in the high-grade malignant lymphomas; (5) ThPh (34 cases) was always elevated in Hodgkin's disease, but low in Burkitt's lymphoma and LL; thus, they had a high TK:ThPh ratio that could be useful in predicting clinical response to thymidine treatment. The authors think that taken together, multiple enzyme determinations could be useful in the characterization of human lymphomas.
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PMID:Multienzymatic analyses of human malignant lymphomas. Correlation of enzymatic data with pathologic and ultrastructural findings in Burkitt's and lymphoblastic lymphomas. 642 36


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