Generation of diversity in retroviruses.

Publisher: Annual Reviews Country of Publication: United States NLM ID: 0117605 Publication Model: Print Cited Medium: Print ISSN: 0066-4197 (Print) Linking ISSN: 00664197 NLM ISO Abbreviation: Annu Rev Genet Subsets: MEDLINE

Publication: Palo Alto Ca : Annual Reviews
Original Publication: Palo Alto, Calif., Annual Reviews, inc.

Genetic Variation*; Retroviridae/*genetics; Animals ; Biological Evolution ; Gene Rearrangement ; Humans ; Mutation ; RNA-Directed DNA Polymerase/genetics ; RNA-Directed DNA Polymerase/metabolism ; Recombination, Genetic ; Retroviridae/enzymology ; Retroviridae/physiology ; Virus Replication

Retroviruses are unique in that their propagation includes transfer of genetic information from RNA to DNA. Two enzymes (RT and RNA polymerase II) that participate in their replication process do not encode editing functions and are thus "error prone." Current estimates indicate that up to one nucleotide substitution per genome occurs per retrovirus replication cycle. In addition, rearrangements can occur during reverse transcription. These mutations result in viral populations in which the wild-type sequence can only be defined by consensus. Retroviruses are also unusual among viruses in their high recombination frequency, which is the result of the copackaging, and then reverse transcribing of two different RNA genomes in the same particle. Recombinants are formed during copying of RNA templates into DNA. With the ability to mutate and recombine genetic information at a higher rate, retroviral populations are poised to respond to selective forces, which may increase or decrease replication of particular genotypes. Interspecies transmission of retroviruses or retroviral genes also likely plays a role in generating diversity. Endogenous proviruses exist in the germline of many vertebrates; pedigrees indicate that recent infections of the germline have also occurred. Thus, the selective forces that mold the retroviral genome may be opposing: selection for efficient replication as exogenous viruses versus selection for passive replication as endogenous proviruses. The latter may be more advantageous over the course of evolution since the survival of the retrovirus is ensured by survival of the host organism. Segments of endogenous viruses may reappear in exogenous viruses through recombination and thus these endogenous sequences are perpetuated.

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CA-06927 United States CA NCI NIH HHS; CA-48703 United States CA NCI NIH HHS; RR-05539 United States RR NCRR NIH HHS

EC 2.7.7.49 (RNA-Directed DNA Polymerase)

Date Created: 19900101 Date Completed: 19910520 Latest Revision: 20101118

20221213

10.1146/annurev.ge.24.120190.002205

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