Figure 1

Domain organization of SPs of selected retroviruses. The tripartite composition of retroviral SPs was analyzed using PHOBIUS [55], SignalP [56] and TMD [57]. Characteristic domains in representative exogenous and endogenous prototypes of each Retroviridae class are shown. Betaretroviruses are further classified based on an earlier retrovirus taxonomy. See text for details on N-terminal extremity (N); central hydrophobic core (h); C-terminal extremity (c). Numbers indicate start and end positions, in aa, of each domain. RSV: Rous Sarcoma Virus; MMTV: Mouse Mammary Tumor Virus; HERV-K(HML-2): Human Endogenous Retrovirus type K subfamily HML-2; JSRV: Jaagsiekte Sheep Retrovirus; MPMV: Mason Pfizer Monkey Retrovirus; HERV-W: Human Endogenous Retrovirus type W; MLV Mo: Moloney Murine Leukemia Virus; HERV-FRD: Human Endogenous Retrovirus type FRD; HTLV-1: Human T-cell Leukemia Virus 1; HFV: Human Foamy Virus. HIV-1/HIV-2: Human Immunodeficiency Virus 1 and 2; SIVmac: Simian Immunodeficiency Virus, acaque isolate; Visna: Maedi-Visna Virus.