• Korean Journal of Microbiology
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• v.46 no.1
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• pp.15-20
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• 2010

Xenotransplantation of pig organs is complicated by the existence of polytropic replication-competent porcine endogenous retroviruses (PERV) capable of infecting human cells. Two classes of infectious human-tropic replication-competent PERVs (PERV-A and PERV-B) and one class of ecotropic PERV-C are known. The potential for recombination between ecotropic PERV-C and human-tropic PERVs adds another level of infectious risk. A recombinant PERV-A/C (PERV-A14/220) virus is 500-fold more infectious than PERV-A. Two determinants of this high infectivity was identified; one was isoleucine-to-valine substitution at position 140 in RBD (receptor binding domain), and the other lies within the PRR (proline rich region) of the envelope protein. To examine whether the effects of the cytoplasmic tail of the PERV-C Env on fusogenesity also influences infectivity, we constructed a pseudotype retroviral vectors containing MoMLV core protein and PERV envelopes. Pseudotyping experiments with the PERV envelope glycoproteins indicated that recombinant PERV-A/C virus is 10-fold more infectious than PERV-A by lacZ staining. This result supports the suggestion that viral transduction of PERV-A/C is enhanced by a membrane-proximal cytoplasmic amphiphilic ${\alpha}$-helix in PERV-C Env tail.

• Tuberculosis and Respiratory Diseases
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• v.49 no.3
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• pp.298-309
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• 2000

Background : The antitumor effects of herpes simplex virus thymidine kinase (HSV-tk) and ganciclovir (GCV) strategies for cancer gene therapy have a the following advantages : 1) a direct cytotoxicity to HSV-tk modified cancer cells by GCV 2) a cell death by the local transfer of toxic metabolites from the HSV-tk modified cells to nearby unmodified tumor cells (bystander effect), and 3) in vivo bystander effect such as antitumor-immunity. Retroviral and adenoviral sequences can silence transgene expression in cells and mice. In this study, we investigated the above described advantages of HSV-tk/GCV strategy in Lewis lung cell and mouse lung cancer model using retroviral vector and adenoviral vector. Also, we observed whether the expression of a silenced gene can be reactivated by treating cells with butyrate. Methods : Retrovirus-HSV-tk and adenovirus-HSV-tk vectors were used for the transduction of Lewis lung carcinoma (LLC) cells. The change of HSV-tk expression by butyrate was measured by Western blol The antitumor activities containing bystander effect were observed in vivo (by MTT assay) and in vivo tumor models of various combinations of LLC and LLC-tk. Results : 1. Butyrate induced the enhancement of HSV-tk expression from adenovirally transduced cells but not from retrovirally transduced cells. 2. Both retrovirus-HSV-tk and adenovirus-HSV-tk vectors with GCV treatment were effective for killing of tumor cell in vitro and suppression of LLC tumorigenicity. Bystander effect was responsible for killing of mixture of LLC-tk and LLC in vitro and in vivo-tumorigenicity model. Conclusion : Butyrate could augment adenovirus-mediated HSV -tk gene expression. Cancer gene therapy with HSV-tk suicide gene by retroviral and adenoviral vector seems to be an effective approach for lung cancer therapy.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.405-414
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• 2007

Pigs have been considered as an ideal source of donor organs because of their plentiful supply and their numerous anatomical and physiological similarities to the human in xenotransplantation. However, for the public health risks associated with the potential for porcine endogenous retrovirus(PERV) infection through xenograft from pig to human, the investigation of methods for elimination and/or control of PERV has been required. In this study we developed the detection and classification methods for PERV based on PCR using specific primers. PERV-A and PERV-B were found in all pigs including Berkshire, Duroc, Landrace, Yorkshire, miniature pig, and Korean native black pig from Jeju by PCR with type-specific primers for PERV. However, PERV-C was detected only from Duroc, miniature pig, and Korean native black pig from Jeju. PERV-A and PERV-B could be distinguished by PCR-RFLP with BamHI. These methods for PERV will be useful in rapid screening of safe organ for xenograft, furthermore, helpful in monitoring of PERV during and after xenotransplantation.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.829-834
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• 2006

LP-BM5 murine leukemia retrovirus induces the immune dysfunction by imbalanced secretion of Th1 and Th2 cytokines in the murine AIDS model. In the present study, it was investigated whether pycnogenol (Pyc) administration could deactivate $NF-{\kappa}B$ to regulate the gene expression of Th1 and Th2 cytokines in C57BL/6 mice with murine AIDS. Treatment with Pyc for 12 weeks significantly inhibited the loss of body weight and enlargement of spleen and lymph node usually seen with AIDS. Moreover, Pyc increased the plasma level of Th1 cytokines, IL-2 and $IFN-{\gamma}$, while reducing the plasma level of Th2 cytokines, IL-6, IL-10, and $TNF-{\alpha}$. In primary culture of splenocytes, mRNA expression of Th2 cytokines was suppressed, but that of Th1 cytokines was not affected. The LP-BM5 retrovirus infection stimulated the cytoplasmic activation of $NF-{\kappa}B$ and nuclear translocation of $I-{\kappa}B$, whereas Pyc administration significantly reduced $NF-{\kappa}B$ activation and $I-{\kappa}B$ degradation. These results suggested that the inhibitory effect of Pyc on Th2 cytokines in mice with murine AIDS was dependent on suppression of the $NF-{\kappa}B$ signaling pathway and was not dependent on $INF-{\gamma}$ level, which regulates Th2 cytokines.

• Journal of Life Science
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• v.13 no.3
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• pp.291-297
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• 2003

A human endogenous retroviral family (HERV-W) has recently been described that is related to multiple sclerosis-associated retrovirus (MSRV) sequences that have been identified in particles recovered from monocyte cultures from patients with multiple sclerosis. Two pol fragments (HWP-FB10 and HWP-FBl2) of HERV-W family were identified and analysed by the PCR approach with cDNA library of human fetal brain. They showed 89 percent nucleotide sequence similarity with that of the HERV-W (accession no. AF009668). Deletion/insertion or point mutation in the coding region of the pol fragments from human fetal brain resulted in amino acid frameshift that induced a mutated protein. Phylogenetic analysis of the HERV-W family from GenBank database indicates that the HWP-FB10 is very closely related to the AC000064 derived from human chromosome 7q21-q22. Further studies on the genetic relationship with neighbouring genes and functional role of these new HERV-W pol sequences are indicated.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.429-437
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• 2000

This study investigated the successful introduction of genes of erythropoietin (EPO) and enhanced green fluorescent protein (EGFP) in bovine embryos following nuclear transfer of bovine fetal fibroblasts (bFF), which were transfected by retrovirus vector system. Non-starved bFF were, transferred into perivitelline space of enucleated oocytes. The bFF-oocyte units were accomplished by cell to cell fusion and activated with calcium inophore and 6-dimethylaminopurine. Reconstructed embryos were co-cultured with bovine oviduct epithelial cells in CRlaa medium for 8 days. Out of 187 (EPO) and 210 (EGFP) bovine eggs reconstructed by nuclear transfer, 149 (EPO : 80.0%) and 158 (EGFP : 75.2%) embryos were cleaved, and among them 36 (EPO : 24.2%) and 35 (EGFP : 22.2%) embryos developed to the blastocyst stage. Of these blastocysts, 100% integration of EPO gene in 36 embryos was determined by PCR, and 100% expression of EGFP gene in 35 embryos was observed under the fluorescent microscope. This result indicates that bovine oocytes reconstructed by nuclear transfer of transfected bFF can successfully develop to the blastocyst stage. Furthermore, this novel procedure may be presumably an attractive method efficiently to produce the transgenic cattles.

• Genomics & Informatics
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• v.20 no.4
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• pp.44.1-44.13
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• 2022

Brugada syndrome (BS) is an autosomal dominant inheritance cardiac arrhythmia disorder associated with sudden death in young adults. Thailand has the highest prevalence of BS worldwide, and over 60% of patients with BS still have unclear disease etiology. Here, we performed a new viral metagenome analysis pipeline called VIRIN and validated it with whole genome sequencing (WGS) data of HeLa cell lines and hepatocellular carcinoma. Then the VIRIN pipeline was applied to identify viral integration positions from unmapped WGS data of Thai males, including 100 BS patients (case) and 100 controls. Even though the sample preparation had no viral enrichment step, we can identify several virus genes from our analysis pipeline. The predominance of human endogenous retrovirus K (HERV-K) viruses was found in both cases and controls by blastn and blastx analysis. This study is the first report on the full-length HERV-K assembled genomes in the Thai population. Furthermore, the HERV-K integration breakpoint positions were validated and compared between the case and control datasets. Interestingly, Brugada cases contained HERV-K integration breakpoints at promoters five times more often than controls. Overall, the highlight of this study is the BS-specific HERV-K breakpoint positions that were found at the gene coding region "NBPF11" (n = 9), "NBPF12" (n = 8) and long non-coding RNA (lncRNA) "PCAT14" (n = 4) region. The genes and the lncRNA have been reported to be associated with congenital heart and arterial diseases. These findings provide another aspect of the BS etiology associated with viral genome integrations within the human genome.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.215-220
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• 2009

The prevalence of potentially xenozoonotic viruses in the reproductive tract of female pigs in Korea was investigated by polymerase chain reaction (PCR). These viruses include porcine endogenous retrovirus (PERV), porcine reproductive and respiratory syndrome virus (PRRSV), swine hepatitis E virus (SHEV), porcine lymphotropic herpesvirus (PLHV), and porcine circovirus type 2 (PCV-2). Histopathological examination and PCR analysis were conducted using the ovaries of 70 slaughtered pigs that were collected from 14 farms in Jeju. Histopathologically, infiltrations of mononuclear inflammatory cells around the thick-walled coiled vessels in the ovarian medulla were observed in 15 cases. Based on the PCR method, PERV, PLHV, PRRSV, SHEV, and PCV-2 were detected in 69 (98.6%), 35 (50%), 5 (7.1%), 4 (5.7%), and 1 sample (1.4%), respectively. These results suggest that PERV and PLHV are the major xenozoonotic viruses in the porcine ovary. This study should aid in the development of a monitoring protocol for potential xenozoonotic agents and in the production of germ-free pigs for xenotransplantation.

• Reproductive and Developmental Biology
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• v.40 no.1
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• pp.7-13
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• 2016

Effectiveness of transgene transfer into genome is crucially concerned in mass production of the bio-pharmaceuticals using genetically modified transgenic animals as a bioreactor. Recently, the mammary gland has been considered as a potential bioreactor for the mass production of the bio-pharmaceuticals, which appears to be capable of appropriate post-translational modifications of recombinant proteins. The mammary gland tissue specific vector system may be helpful in solving serious physiological disturbance problems which have been a major obstacle in successful production of transgenic animals. In this study, to minimize physiological disturbance caused by constitutive over-expression of the exogenous gene, we constructed new retrovirus vector system designed for mammary gland-specific expression of the hEPO gene. Using piggyBac vector system, we designed to express hEPO gene under the control of mammary gland tissue specific and lactogenic hormonal inducible goat ${\beta}$-casein or mouse Whey Acidic Protein (mWAP) promoter. Inducible expression of the hEPO gene was confirmed using RT-PCR and ELISA in the mouse mammary gland cells treated with lactogenic hormone. We expect the vector system may optimize production efficiency of transgenic animal and reduce the risk of global expression of transgene.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.508-513
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• 2002

Human endogenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes located nearby. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases. The HERV-W family has been identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using a cDNA library derived from a human brain, the HERV-W LTR elements were examined and five new LTR elements were identified. These elements were examined using a YAC clone panel from the Xq21.3 region linked to psychosis that was replicated on the Y chromosome after the separation of the chimpanzee and human lineages. Fourteen elements of the HERV-W LTR were identified in that region. Those LTR elements showed a high degree of sequence similarity ($91.8-99.5\%$) with previously reported HERV-W LTR. A phylogenetic tree obtained from the neighbor-joining method revealed that new HERV-W LTR elements were closely related to the AXt000960, AF072504, and AF072506 from the GenBank database. The data indicates that several copy numbers of the HERV-W LTR elements exist on the Xq21.3 region and are also expressed in the human brain. These LTR elements need to be further investigated as potential leads to neuropsychiatric diseases.