B lymphoma Moloney murine leukemia virus insertion region 1: An oncogenic mediator in prostate cancer / 亚洲男科学杂志(英文版)

B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1), a core member of polycomb repressive complex 1 (PRC1), has been intensely investigated in the field of cancer epigenetics for decades. Widely known as a critical regulator in cellular physiology, BMI1 is essential in self-renewal and differentiation in different lineages of stem cells. BMI1 also plays a significant role in cancer etiology for its involvement in pathological progress such as epithelial-mesenchymal transition (EMT) and cancer stem cell maintenance, propagation, and differentiation. Importantly, overexpression of BMI1 is predictive for drug resistance, tumor recurrence, and eventual therapy failure of various cancer subtypes, which renders the pharmacological targeting at BMI1 as a novel and promising therapeutic approach. The study on prostate cancer, a prevalent hormone-related cancer among men, has promoted enormous research advancements in cancer genetics and epigenetics. This review summarizes the role of BMI1 as an oncogenic and epigenetic regulator in tumor initiation, progression, and relapse of prostate cancer.

Host factor Moloney leukemia virus 10 (MOV10) protein inhibits replication of the xenotropic murine leukemia virus-related virus (XMRV) / 病毒学报

We investigated inhibition of Moloney leukemia virus 10 (MOV10) upon xenotropic murine leukemia virus-related virus (XMRV) and made a preliminary study of the mechanism of action. Using transfection, infection, western blotting and real-time polymerase chain reaction, we found that MOV10 inhibited XMRV replication. Using MOV10 overexpressed in viral producer cells, MOV10 was shown to reduce the infectivity of XMRV. MOV10 could be incorporated into XMRV, suggesting that MOV10 could undergo encapsidation by XMRV during viral assembly. MOV10 could also restrict the DNA production of XMRV in target cells. We found that the putative RNA-helicase domain of MOV10 maintained most of its XMRV inhibition. These results suggest that MOV10 could be required during the retroviral lifecycle. Perturbation of MOV10 disrupts the generation of infectious viral particles, suggesting that MOV10 has broad antiretroviral activity. Hence, MOV10 could be actively involved in host defense against retroviral infection.

Prokaryotic expression and purification of moloney murine leukemia virus reverse transcriptase and verification of the activity / 生物工程学报

To produce the reverse transcriptase of moloney murine leukemia virus (MMLV-RT) through gene recombination, MMLV-rt gene was amplified by polymerase chain reaction (PCR) with specifically designed primers bearing restriction enzyme sites. Five mutation sites increasing the solution of the target protein were introduced through Site-directed mutation. After verification by sequencing, the gene was cloned into the expression vector pET15b to construct the recombinant plasmid pET15b-MMLV-rt. Purified MMLV-RT was obtained by affinity chromatography (Ni3+-NTA beads). Molecular weight and purity of MMLV-RT were analyzed with SDS-PAGE. Enzyme activity was characterized with RT-PCR. We successfully constructed the recombinant plasmid pET15b-MMLV-rt and obtained the MMLV-RT fusion protein with 6His on the N-terminus. Recombinant protein was purified through Ni3+-NTA beads based affinity chromatography, the purity of which was 96%. The Activity of the enzyme was high. MMLV-RT of 96% purity was obtained with the prokaryotic expression technique, which serves as the basis for mass production of this enzyme.

Characterization of the long-terminal repeat single-strand tail-binding site of Moloney-MuLV integrase by crosslinking

Processing of viral DNA by retroviral integrase leaves a dinucleotide single-strand overhang in the unprocessed strand. Previous studies have stressed the importance of the 5' single-stranded (ss) tail in the integration process. To characterize the ss-tail binding site on M-MuLV integrase, we carried out crosslinking studies utilizing a disintegration substrate that mimics the covalent intermediate formed during integration. This substrate carried reactive groups at the 5' ss tail. A bromoacetyl derivative with a side chain of 6 A was crosslinked to the mutant IN 106-404, which lacks the N-terminal domain, yielding a crosslinked complex of 50 kDa. Treatment of IN 106-404 with N-ethylmaleimide (NEM) prevented crosslinking, suggesting that Cys209 was involved in the reaction. The reactivity of Cys209 was confirmed by crosslinking of a more specific derivative carrying maleimide groups that spans 8A approximately. In contrast, WT IN was not reactive, suggesting that the N-terminal domain modifies the reactivity of the Cys209 or the positioning of the crosslinker side chain. A similar oligonucleotide-carrying iodouridine at the 5'ss tail reacted with both IN 106-404 and WT IN upon UV irradiation. This reaction was also prevented by NEM, suggesting that the ss-tail positions near a peptide region that includes Cys209.

Study on cephalopod's ink for anti-retroviral activity.

Aqueous extracts of ink from four cephalopods, adult and young Sepiella inermis and Loligo duvaucelli were tested against Moloney murine leukaemia virus reverse transcriptase (MMLV RT). Ink from young cephalopods, S. intermis and L. duvaucelli showed strong inhibition of MMLV RT.

Enhancement of thermal effect in virally infected mammalian cells in vitro and its modification by chlorpromazine.

NIH/3T3 cells chronically infected with Moloney murine leukemia virus (M-MuLV) were more thermosensitive than uninfected cells. Cells upregulated by a primary dose of heat formed giant colonies and had an altered response to a second dose of heat. Thermosensitivity depended upon the time elapsed between heat treatments. Heating the cells at either 42 degrees or 42.5 degrees C yielded biphasic survival curves, indicating a mixed population of productively infected and quiescent cells. Hyperthermia at 43 degrees C abolished this effect. Thermal sensitivity of infected cells was correlated with the expression of a viral reporter protein. Chlorpromazine (CPZ), a membrane active drug potentiated the heat effect in both uninfected and virally infected cells. The drug also abolished the biphasic effect of heat in infected cells, suggesting that heat sensitivity of both productively and quiescent cells is membrane mediated. The combined effect of heat at 42.5 degrees C and CPZ was equivalent to the effect of heat alone at 43.5 degrees C. These observations indicate that heat can selectively be lethal to productively infected cells and the membrane active drugs could further amplify this hyperthermic effect.

Effect of Retinoic Acid on Growth and Transduced Tumor Necrosis Factor-alpha Gene Expression of Human Bladder Tumor Cell Lines / 대한비뇨기과학회지

INTRODUCTION AND OBJECTIVES: Retinoic acid (RA) is known as a potent chemopreventive agent in bladder tumor. Recently, RA has gained attention for up-regulation of transduced gene expression via long terminal repeat (LTR) transcriptional promotion. In this study, we investigated the possible dual effect of RA, growth inhibition and up-regulation of transduced gene expression which contains LTR promoter in human bladder carcinoma cell lines. MATERIALS AND METHODS: Human bladder carcinoma cell lines CY-24, J-82, HT-1197, ATCC) were transduced with Moloney murine leukemia virus containing cDNA of TNF-alpha. The growth of transduced and parent cell line was measured by tetrazolium based colorimetric assay (MTF). Transduced TNF-alpha gene expression was determined by ELISA method. RESULTS: TNF-alpha production was increased approximately twofold after treatment with RA (10 uM) in all three cell lines. This increase was dependent on RA concentration. RA treatment of transduced and parent cell line resulted in dose dependent inhibition of cell proliferation(up to 80% inhibitionwith 10 uM RA) in all parental and transduced cell lines. CONCLUSIONS: These results indicate that RA shows dual effect in cytokine gene transduced bladder carcinoma cells with retroviral vector containing LTR promoter and could be a supplement to the gene therapy of bladder cancer.

Pathogenesis of age dependent paralysis by a temperature sensitive mutant (tsl) of Moloney murine leukemia virus-TB.

The tsl mutant of Moloney murine leukemia virus-TB produces neurological disease leading to fatal hind limb paralysis when inoculated in newborn BALB/c mice. The present study was under taken to assess the role of T and B lymphocytes in age dependent resistance to tsl induced paralysis in BALB/c mice. The adoptive transfer of non-immune splenic unseparated lymphoid cells, T cells and B cells and tsl immune B cells and T cells to newborn BALB/c mice infected with tsl did not prevent the development of paralysis. However, adoptive transfer of immune splenic unseparated lymphoid cells and immune T cells delayed the onset of paralysis by 5 to 10 days as compared to the mice which did not receive the immune lymphocytes. Athymic BALB/c nude mice inoculated with tsl at days 1 and 10 after birth failed to develop the paralytic disease. Transfer of tsl neutralising antibody also delayed the onset of paralysis. Mice (10 days old) treated with cyclophosphamide, cyclosporine A, cortisone acetate and anti-T cell serum when inoculated with tsl also did not develop neurological disease. The results suggest that age related resistance to neurological disease may not be associated with B cell mediated immunity.

Characterization of a continuous lymphocyte cell line derived from BALB/c mice inoculated with a recombinant Moloney murine leukemia virus-TB.

Neonatal BALB/c mice were inoculated (ip) with a recombinant Moloney murine leukemia virus-TB. Majority of the inoculated mice developed lymphoma within 5-7 months post infection. The cells from splenic lymphomas were cultured and 3 continuous cell lines (GP1, GP2 and GP3) developed. GP1 was single cell cloned and characterized. Based on Thy 1.2 (98.4%) phenotypic marker, the cell line was categorized as T cell line. The percent positivity for different cell surface markers on analysis with FACS was 98.4, 4.8, 5.5, 2.2, 1.8, 1.2 and 9.5 for Thy 1.2, mu, L3T4, Lyt2, Ia, IL2R and PNA receptor, respectively. A total of 16.5% GP1 cells was also positive for Moloney murine leukemia virus envelope protein (gp 70). Incomplete retrovirus like particles were demonstrated in the cytoplasm of GP1 cells by electron microscopy. The cell line on inoculation(ip) in neonatal BALB/c mice produced lymphomic lesions in almost all the vital organs of the mice.