Endogenous retrovirus
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Endogenous retroviruses are retroviruses thought to be derived from ancient infections of germ cells in humans and mammals; as such their proviruses are passed on to the next generation and as such now remain in the genome. Retroviruses are viruses that reverse-transcribe their RNA into DNA for integration into the host's genome. Most retroviruses (such as HIV-1) infect somatic cells, but some can also infect germline cells and once they have done so they are termed endogenous. Endogenous retroviruses can persist in the genome of their host for long periods, tens of millions of years in some cases. However, they are generally only infectious for a short time after integration as they acquire 'knockout' mutations during host DNA replication.
Human endogenous retroviruses (HERVs) are suspected of involvement in some autoimmune diseases, in particular with multiple sclerosis. Investigations of retroviruses with respect to the HELLP syndrome and pre-eclampsia are thought to be also related. There are many thousands of endogenous retroviruses within human DNA but all are defective and cannot produce infectious virus particles. This is because most are just ancient fossils, having first integrated tens of millions of years ago. However, there is one group (or family) of viruses that have been active since the divergence of humans and chimpanzees. This family, termed HERV-K(HML2), is one of the most studied and there are indications it has even been active in the past few hundred thousand years, as some human individuals carry more copies of the virus family than others.
See also
Online HERV databases
External links
- Roswitha Löwer, Jophannes Löwer, Reinhard Kurth, (1996). ["The viruses in all of us: Characteristics and biological significance of human endogenous retrovirus sequences"] Proceedings of the National Academy of Sciences. 93:5177-5184
- Moles JP, Tesniere A, Guilhou JJ. ["A new endogenous retroviral sequence is expressed in skin of patients with psoriasis."] British Journal of Dermatology. 2005 Jul;153(1):83-9.
- Seifarth W, Frank O, Zeilfelder U, Spiess B, Greenwood AD, Hehlmann R, Leib-Mosch C. ["Comprehensive analysis of human endogenous retrovirus transcriptional activity in human tissues with a retrovirus-specific microarray."] Journal of Virology. 2005 Jan;79(1):341-352.
- Knerr I, Beinder E, Rascher W. ["Syncytin, a novel human endogenous retroviral gene in human placenta: evidence for its dysregulation in preeclampsia and HELLP syndrome."] American Journal of Obstestrics and Gynecolology. 2002 Feb;186(2):210-213.
- Gifford R, Tristem M. ["The evolution, distribution and diversity of endogenous retroviruses."] Virus Genes. 2003 May;26(3):291-315.
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