• Journal of Life Science
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• v.25 no.4
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• pp.481-485
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• 2015

Retroviruses genes have been inserted into the human genome for millions of years. These retroviruses are now inactive due to mutations such as deletions or nonsense mutations. After mutation, retroviruses eventually became fixed in the genome in their endogenous forms and existed as traces of ancient viruses. These retroviruses are called endogenous retroviruses (ERVs), with the human form known as human endogenous retrovirus. HERV cannot become a fully active virus, but a number of viral proteins or even virus particles are expressed under various conditions. Compared to endogenous retroviruses, some exogenous retroviruses are still infectious and can threaten human life. Among these, human immunodeficiency virus (HIV) is one of the most well-known and best-studied. Recent studies have shown some elements of HERV were activated by HIV infection and interact with HIV-derived proteins. In addition, many studies have attempted to use HERV as vaccination against HIV infection. This review will describe the regulation and interaction between HERV and HIV infection and mention the development of vaccines and therapeutic agents against HIV infection by using HERV elements.

• RED RIBBON
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• s.70
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• pp.10-11
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• 2006

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1572-1575
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• 2008

The xenotransplantation of pig organs and cells can be related with a risk of transmission of infectious diseases to human. Previous findings indicate that the regulatory region of PERV for retroviral transcription, replication and integration into the cellular DNA is located on the 5' Long Terminal Repeat (LTR). The objective of this study is the investigation of methylation and deletion status of the PERV 5' LTR region which can be used for regulating PERV expression. We compared the sequences of genomic DNA and bisulfite-treated genomic DNA from PK-15 cells expressing PERV to observe the methylation status of the 5' LTR. Our results showed that the CpG sites of U3 were methylated and methylation was inconsistent in the R and U5 regions. Also, variable numbers of 18 bp repeats and 21 bp repeats were detected on 5' LTR by sequencing analysis. The consistent U3 methylation might be indicative of host suppression of expression of the retroviruses.

• Molecules and Cells
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• v.44 no.12
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• pp.861-878
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• 2021

The human genome contains many retroviral elements called human endogenous retroviruses (HERVs), resulting from the integration of retroviruses throughout evolution. HERVs once were considered inactive junk because they are not replication-competent, primarily localized in the heterochromatin, and silenced by methylation. But HERVs are now clearly shown to actively regulate gene expression in various physiological and pathological conditions such as developmental processes, immune regulation, cancers, autoimmune diseases, and neurological disorders. Recent studies report that HERVs are activated in patients suffering from coronavirus disease 2019 (COVID-19), the current pandemic caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. In this review, we describe internal and external factors that influence HERV activities. We also present evidence showing the gene regulatory activity of HERV LTRs (long terminal repeats) in model organisms such as mice, rats, zebrafish, and invertebrate models of worms and flies. Finally, we discuss several molecular and cellular pathways involving various transcription factors and receptors, through which HERVs affect downstream cellular and physiological events such as epigenetic modifications, calcium influx, protein phosphorylation, and cytokine release. Understanding how HERVs participate in various physiological and pathological processes will help develop a strategy to generate effective therapeutic approaches targeting HERVs.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.226.4-226
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• 2005

• Proceedings of the Korean Society of Life Science Conference
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• 2000.12a
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• pp.3-11
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• 2000

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.111-112
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• 2000

• Proceedings of the Microbiological Society of Korea Conference
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• 2008.05a
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• pp.72-73
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• 2008

• Korean Journal of Agricultural Science
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• v.30 no.1
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• pp.59-65
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• 2003

To investigate the relationship of endogenous retroviruses in peccaries and pigs, a set of degenerate primers was used in this study to amplify peccary retroviral sequences. The sequences of two putative retroviral clones showed close homology to mouse and pig retroviral sequences. The peccary endogenous retroviral sequences are significant in that they are the first such sequences reported in peccary species and repudiate old claims in the literature that peccaries do not have C-type retroviral sequences.

• BMB Reports
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• v.45 no.4
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• pp.207-212
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• 2012

Retroviruses have often been used for gene therapy because of their capacity for the long-term expression of transgenes via stable integration into the host genome. However, retroviral integration can also result in the transformation of normal cells into cancer cells, as demonstrated by the incidence of leukemia in a recent retroviral gene therapy trial in Europe. This unfortunate outcome has led to the rapid initiation of studies examining various biological and pathological aspects of retroviral integration. This review summarizes recent findings from these studies, including the global integration patterns of various types of retroviruses, viral and cellular determinants of integration, implications of integration for gene therapy and retrovirus-mediated infectious diseases, and strategies to shift integration to safe host genomic loci. A more comprehensive and mechanistic understanding of retroviral integration processes will eventually make it possible to generate safer retroviral vector platforms in the near future.