Retroviruses and primate evolution
ABSTRACT Human endogenous retroviruses (HERVs), probably representing footprints of ancient germ-cell retroviral infections, occupy about 1% of the human genome. HERVs can influence genome regulation through expression of retroviral genes, either via genomic rearrangements following HERV integrations or through the involvement of HERV LTRs in the regulation of gene expression. Some HERVs emerged in the genome over 30 MYr ago, while others have appeared rather recently, at about the time of hominid and ape lineages divergence. HERVs might have conferred antiviral resistance on early human ancestors, thus helping them to survive. Furthermore, newly integrated HERVs could have changed the pattern of gene expression and therefore played a significant role in the evolution and divergence of Hominoidea superfamily. Comparative analysis of HERVs, HERV LTRs, neighboring genes, and their regulatory interplay in the human and ape genomes will help us to understand the possible impact of HERVs on evolution and genome regulation in the primates. BioEssays 22:161-171, 2000.
- SourceAvailable from: Anton Buzdin
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- "Retroelements constitute more than 42% of human DNA and are at present the only class of transs posable elements in mammals capable of transposition (Sverdlov, 2000; Buzdin, 2004). They also play an active role in a multitude of processes of functioning of the human genome (Wessler, 1998; Sverdlov, 1998, 2000; Deininger et al., 2003; Buzdin, 2004). "
ABSTRACT: Mobile elements are DNA fragments that are able to self-replicate within the genome of a host organism. Usually, mobile elements comprise about 40-50% of mammalian genome. In the present review, evolutionary recent insertions of mobile elements are considered which have occurred after divergence of human and chimpanzee ancestral forms, i.e. later than about 6 million years. Human-specific transposable elements are represented by relatively small number of copies that can be subdivided into four groups: HERV-K (HML-2), L1, Alu, and SVA. The number of human-specific copies of HERV-K (HML-2), L1, Alu, and SVA representatives amounts roughly to 150, 1200, 5500, and 860 copies per genome respectively. Furthermore, we succeeded in describing a new family of human-specific mobile elements that are present only in human genome and are absent in other primates. Insertions of human-specific mobile elements can be regarded as important candidates for the role of molecular-genetic agents of anthropogenesis--each new insertion of such a mobile element supplies the acceptor gene locus with the set of new functional sites for binding transcription factors that can make significant alterations to adjacent genes functioning. On the basis of known evidences confirming the influence of human-specific mobile elements on adjacent genes expression, total number of human genes regulated by them can be estimated like hundreds.Zhurnal obshcheĭ biologii 09/2012; 73(1):3-20. DOI:10.1134/S2079086412050027 · 0.12 Impact Factor
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- "Such integrated proviruses are known as endogenous retroviruses (ERVs) (Gifford & Tristem, 2003; Weiss, 2006) and can occur in either expressed or silent forms, and as complete or partial (defective) genomes. ERVs can influence host evolution, either via genomic rearrangements (Hughes & Coffin, 2001) or through the regulation of gene expression (Sverdlov, 2000; Jern & Coffin, 2008). "
ABSTRACT: A previous phylogenetic study suggested that mammalian gammaretroviruses may have originated in bats. Here we report the discovery of RNA transcripts from two putative endogenous gammaretroviruses in frugivorous (Rousettus leschenaultii retrovirus, RlRV) and insectivorous (Megaderma lyra retrovirus, MlRV) bat species. Both genomes possess a large deletion in pol, indicating that they are defective retroviruses. Phylogenetic analysis places RlRV and MlRV within the diversity of mammalian gammaretroviruses, with the former falling closer to porcine endogenous retroviruses and the latter to Mus dunni endogenous virus, koala retrovirus and gibbon ape leukemia virus. Additional genomic mining suggests that both microbat (Myotis lucifugus) and megabat (Pteropus vampyrus) genomes harbour many copies of endogenous retroviral forms related to RlRV and MlRV. Furthermore, phylogenetic analysis reveals the presence of three genetically diverse groups of endogenous gammaretroviruses in bat genomes, with M. lucifugus possessing members of all three groups. Taken together, this study indicates that bats harbour distinct gammaretroviruses and may have played an important role as reservoir hosts during the diversification of mammalian gammaretroviruses.Journal of General Virology 06/2012; 93(Pt 9):2037-45. DOI:10.1099/vir.0.043760-0 · 3.53 Impact Factor
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- "there are 22 independent retroviral families identified (Bannert and Kurth, 2004; Bromham, 1 2002; Buzdin et al, 2002; Hughes and Coffin, 2001; Khodosevich et al, 2002; Sverdlov, 2000, 2 Villarreal, 2004, 2005; Ryan, 2006; Griffith and Voisset, 2008). A quantity of remaining 3 former viral gene embedding repetitive elements embracing an enormous genetic diversity 4 originally accompanied the protein coding sequences as control-and/or identification 5 segments. "
ABSTRACT: In contrast with former definitions of life limited to membrane-bound cellular life forms which feed, grow, metabolise and replicate (i) a role of viruses as genetic symbionts, (ii) along with peripheral phenomena such as cryptobiosis and (iii) the horizontal nature of genetic information acquisition and processing broaden our view of the tree of life. Some researchers insist on the traditional textbook conviction of what is part of the community of life. In a recent review [Moreira, D., Lopez-Garcia, P., 2009. Ten reasons to exclude viruses from the tree of life. Nat. Rev. Microbiol. 7, 306-311.] they assemble four main arguments which should exclude viruses from the tree of life because of their inability to self-sustain and self-replicate, their polyphyly, the cellular origin of their cell-like genes and the volatility of their genomes. In this article we will show that these features are not coherent with current knowledge about viruses but that viral agents play key roles within the roots and stem of the tree of life.Journal of Theoretical Biology 10/2009; 262(4):698-710. DOI:10.1016/j.jtbi.2009.10.014 · 2.30 Impact Factor