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Viruses 2015, 7(3), 1258-1270;

Genetic Diversity of Koala Retroviral Envelopes

Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
Author to whom correspondence should be addressed.
Academic Editor: Welkin Johnson
Received: 11 January 2015 / Revised: 4 March 2015 / Accepted: 11 March 2015 / Published: 17 March 2015
(This article belongs to the Special Issue Endogenous Viruses)
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Genetic diversity, attributable to the low fidelity of reverse transcription, recombination and mutation, is an important feature of infectious retroviruses. Under selective pressure, such as that imposed by superinfection interference, gammaretroviruses commonly adapt their envelope proteins to use alternative receptors to overcome this entry block. The first characterized koala retroviruses KoRV subgroup A (KoRV-A) were remarkable in their absence of envelope genetic variability. Once it was determined that KoRV-A was present in all koalas in US zoos, regardless of their disease status, we sought to isolate a KoRV variant whose presence correlated with neoplastic malignancies. More than a decade after the identification of KoRV-A, we isolated a second subgroup of KoRV, KoRV-B from koalas with lymphomas. The envelope proteins of KoRV-A and KoRV-B are sufficiently divergent to confer the ability to bind and employ distinct receptors for infection. We have now obtained a number of additional KoRV envelope variants. In the present studies we report these variants, and show that they differ from KoRV-A and KoRV-B envelopes in their host range and superinfection interference properties. Thus, there appears to be considerable variation among KoRVs envelope genes suggesting genetic diversity is a factor following the KoRV-A infection process. View Full-Text
Keywords: koala retrovirus (KoRV); endogenous retrovirus (ERV); exogenous retrovirus; recombination koala retrovirus (KoRV); endogenous retrovirus (ERV); exogenous retrovirus; recombination

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Xu, W.; Gorman, K.; Santiago, J.C.; Kluska, K.; Eiden, M.V. Genetic Diversity of Koala Retroviral Envelopes. Viruses 2015, 7, 1258-1270.

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