Simian Retroviruses


Simian retroviruses are enveloped viruses that contain a duplex RNA core. In general, viruses found in nonhuman primates constitute the closest relatives to human viruses, therefore a knowledge of these viruses is important for an understanding of their human counterparts, which induce significant morbidity and mortality.

Keywords: RNA virus; nonhuman primate; simian immunodeficiency virus; simian retrovirus; simian T‐cell lymphotropic virus; foamy virus

Figure 1.

Electron photomicrographs of replicating simian retroviruses in culture, showing the comparative structure of the following viruses; (a) simian immunodeficiency virus in CEMx174 cells; (b) simian T‐cell lymphotropic virus in a cell line established from a seropositive baboon; (c) simian retrovirus in Raji cells; and (4) simian foamy virus growing in a human peripheral blood mononuclear cell culture. Courtesy of Eileen Breeding of the Yerkes Regional Primate Research Center (a–c) and Tom Folks and Cynthia Goldsmith of the Centers for Disease Control and Prevention (d).

Figure 2.

Genomic structure of four simian retroviruses: simian retrovirus (SRV), simian T‐cell lymphotropic virus (STLV), simian immunodeficiency virus (SIV), and simian foamy virus (SFV), showing the known coding regions in the three different ribosomal reading frames. The scale at the bottom illustrates the varying length (kilobases, kb) of the different retroviruses.

Figure 3.

Replication strategy of simian immunodeficiency virus (SIV) as a model for simian retroviruses. Initial binding of SIV is through the CD4 receptor on the surface of the cell. This binding triggers the exposure of the chemokine receptor‐binding domain which allows entry of virus into the cell. Reverse transcription occurs inside the uncoated capsid, which then proceeds to the nucleus to deliver the double‐stranded viral DNA (proviral DNA) to the host chromosome for integration. Transcription of integrated DNA (provirus) produces RNA species for protein production and genomic RNA for capsid assembly. Nonstructural proteins play a role in regulating further transcription and translation to produce structural proteins for virion assembly. Courtesy of Terri Gibson.



Cocchi F, DeVico AL, Garzino‐Demo A et al. (1995) Identification of RANTES, MIP‐1α, and MIP‐1β as the major HIV‐suppressive factors produced by CD8+ T cells. Science 270: 1811–1815.

Feng Y, Broder CC, Kennedy PE and Berger EA (1996) HIV‐1 entry cofactor: functional cDNA cloning of a seven‐transmembrane, G protein‐coupled receptor. Science 272: 872–877.

Fletcher TM III, Brichacek B, Sharova N et al. (1996) Nuclear import and cell cycle arrest functions of the HIV‐1 Vpr protein are encoded by two separate genes in HIV‐2/SIVsm. EMBO Journal 15: 6155–6165.

Franchini G and Reitz MS Jr (1994) Phylogenesis and genetic complexity of the nonhuman primate retroviridae. AIDS Research and Human Retroviruses 10: 1047–1060.

Gao F, Balles E, Robertson DL et al. (1999) Origin of HIV‐1 in the chimpanzee Pan troglodytes troglodytes. Nature 397: 436–441.

Kestler HW, Ringler DJ, Mori K et al. (1991) Importance of the nef gene for maintenance of high virus loads and for the development of AIDS. Cell 65: 651–662.

Lowenstine LJ, Pedersen NC, Higgins J et al. (1986) Seroepidemiologic survey of captive Old‐World primates for antibodies to human and simian retroviruses, and isolation of a lentivirus from sooty mangabeys (Cercocebus atys). International Journal of Cancer 38: 563–574.

Novembre FJ, Lewis MG, Saucier MM et al. (1996) Deletion of the nef gene abrogates the ability of SIVsmmPBj to induce acutely lethal disease in pigtail macaques. AIDS Research and Human Retroviruses 12: 727–736.

Planelles V, Jowett JB, Li QX et al. (1996) Vpr‐induced cell cycle arrest is conserved among primate lentiviruses. Journal of Virology 70: 2516–2524.

Simon JH, Miller DL, Fouchier RA et al. (1998) The regulation of primate immunodeficiency virus infectivity by Vif is cell species restricted: a role for Vif in determining virus host range and cross‐species transmission. EMBO Journal 17: 1259–1267.

Further Reading

Coffin JM (1991) Retroviridae and their replication. In: Fields BN, Knipe DM, Chanock RM et al. (eds) Fundamental Virology 2nd edn, pp. 645–708. New York: Raven Press.

Franchini G and Reitz MS Jr (1994) Phylogenesis and genetic complexity of the nonhuman primate retroviridae. AIDS Research and Human Retroviruses 10: 1047–1060.

Fultz PN (1994) Simian T‐lymphotropic virus type I. In: Levy J (ed.) The Retroviridae, vol. 3, pp. 111–131. New York: Plenum.

Gardner MB (1994) The simian retroviruses. In: Levy J (ed.) The Retroviridae, vol. 3, pp. 133–176. New York: Plenum.

Neumann‐Haefelin D, Fleps U, Renne R and Schweizer M (1993) Foamy viruses. Intervirology 35: 196–207.

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How to Cite close
Novembre, Francis J(Apr 2001) Simian Retroviruses. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0001088]