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

Host-range variants of mouse mammary tumor virus (MMTV) have been isolated that have the ability to productively infect cells in vitro with high efficiency (at multiplicities of infection </=1) and with extremely short latent periods to the production of de novo virus (as short as 4 days after infection). These variants of the highly oncogenic MMTV of RIII, C3H, and GR mice were obtained by serial virus passage in feline cells. The resultant variant stocks react in group-specific radioimmunoassays for the MMTV major external glycoprotein (gp52) and major internal protein (p28), possess a protein profile similar to that of wild-type MMTV, and contain a virion-associated DNA polymerase with a magnesium cation preference. Addition of dexamethasone and insulin to culture media enhances the titer of de novo MMTV to levels of approximately 10(10) particles per 75-cm(2) flask (containing 5 x 10(6) cells) per 24 hr. Variant stocks exhibit no evidence of contamination with either murine or feline type C retroviruses, as assayed by various techniques. The variants of MMTV derived from C3H and RIII mice exhibit differential host ranges that include the ability to productively infect feline, canine, bat, mink, murine, and human cells. Use of these MMTV host-range variants now facilitates the study of the complete replicative cycle of MMTV as well as an elucidation of the interaction of MMTV with various hormones, physical or chemical carcinogens, and tumor promoters in the initiation and promotion of mammary neoplasia.
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PMID:Isolation of host-range variants of mouse mammary tumor viruses that efficiently infect cells in vitro. 21 96

Human breast cyst fluids were shown to contain low concentrations of IgA (15-78 micrograms/ml) and IgG (33-145 micrograms/ml). The IgA:IgG ratios in individual breast cyst fluids ranged from 1:0.6 to 1:4. These levels are considerably higher than their ratio in serum (1:7). IgA from 33% of the 40 fluids examined, and IgG from 10% of the fluids, reacted with the murine mammary tumor virus (MuMTV). The reactivity was detected by an enzyme-linked immunosorbent assay that measures antibody binding to both the envelope glycoprotein and core protein of the virus. In a second series of experiments. IgA from 28% of 40 breast cyst fluids reacted only with MuMTV while IgA from 30% of the fluids was reactive with both MuMTV and the Rauscher murine leukemia virus. Antigen reactive with antiserum to the 28,000-dalton MuMTV core protein (p28), was also identified in a 165,000-g pellet fraction from breast cyst fluids. In individual fluids, the extent of IgA binding to MuMTV was positively correlated (P less than or equal to 0.01) with the binding of anti-p28 antibody to the pellet of the breast cyst fluid. Fractions with the buoyant density of retroviruses (1.16-1.18 g/ml) or their cores (1.21-1.25 g/ml) were isolated from breast cyst fluids. These fractions contained a DNA polymerase capable of utilizing the reverse transcriptase-specific template, dG12-18 x poly rCm. In addition, they reacted with antiserum to MuMTV p 28 but not with antiserum to the 30,000-dalton Rauscher murine leukemia virus core protein.
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PMID:Antigens and antibodies cross-reactive to the murine mammary tumor virus in human breast cyst fluids. 625 13

Short-term cultures of cells from human rain tumours have been reported to synthesise RNA particles of density in the range characteristic of C type RNA retroviruses, with associated DNA polymerase activity. Fresh tumour cells obtained from 6 children with astrocytoma and 7 children with medulloblastoma, together with one sample of normal brain tissue and normal leukocytes from brain tumour patients were assayed by several characteristics for the primate retrovirus. 1 or 6 (17%) astrocytomas and 4 of 7 (57%) medulloblastomas released RNA particles which banded in sucrose gradients at a density of 1.16-1.18 g/cm3 together with a short segment of DNA, which was eliminated by prior ribonuclease treatment and two proteins of 28k and 16k daltons. These findings were compatible with the presence of a primate retrovirus. Immune coprecipitation of 125I-labelled proteins from the 1.16-1.18 g/cm3 gradient region failed to show any reactivity with antisera to p28 core antigens or the p70 reverse transcriptase antigens of simian sarcoma virus, baboon endogenous virus or Mason Pfizer virus. Assays for DNA polymerase activity in culture supernatant fluid showed only a low amount of activity with template preferences not characteristic of the retroviral reverse transcriptase enzyme.
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PMID:Children's brain tumour cells produce RNA particles with incomplete retrovirus characteristics. 628 9

Macrophages are an important defense against in vivo herpes simplex virus (HSV) infection by early cytokine secretion; however, they can be infected by HSV-1 and they may be compromised in their ability to produce cytokines. In this paper, we studied the expression of two Th1 cytokines, interleukin (IL)-12 and IL-27, upon HSV-1 infection of human macrophages, and how it is regulated by treatment with two antiviral drugs exerting their anti-HSV-1 activity through different mechanisms of action. We found that infection does not alter intra-macrophage thiol content, while it induces mRNA expression of IL-12 p35 and IL-12 p40 as well as of IL-27 p28 and IL-27 EBI3, as revealed by RT-PCR. The increased expression of mRNA is accompanied by increased production of IL-12 p40 and IL-27 p28 protein, as detected in the culture supernatants by ELISA. The two antiviral drugs tested were acyclovir (ACV), commonly used to treat herpes virus infections, and an N-butanoyl glutathione (GSH) derivative, GSH-C4. While ACV inhibits viral DNA polymerase, GSH-C4 inhibits virus replication by interfering with protein folding and maturation of viral particles. Indeed, GSH-C4, altering the intracellular redox state, may modulate the Th1/Th2 balance favoring Th1-type response. Our data show that both drugs inhibit HSV-1 replication in macrophages, without significantly affecting cytokine mRNA levels. Nonetheless, lower levels of IL-12 p40 and IL-27 p28 proteins were found in the supernatants of macrophages treated with either GSH-C4 or ACV, likely as an indirect consequence of inhibited HSV-1 replication.
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PMID:Effect of the N-butanoyl glutathione (GSH) derivative and acyclovir on HSV-1 replication and Th1 cytokine expression in human macrophages. 2468 16