An endogenous virus that replicates with the genome of the host and is benign but that will produce infective virus particles if it infects cells of a different species. Murine endogenous leukaemia viruses fall into three categories: ecotropic, that will replicate only in mouse cells; xenotropic, that will replicate only in nonmouse cells; and amphotropic or polytropic, that will replicate in a wide range of mammalian cells including murine cells. The differences arise largely due to envelope proteins that determine binding and infectivity. The xenotropic virus receptor (xenotropic and polytropic retrovirus receptor, XPR1) has multiple membrane-spanning domains and may play a role in G-protein-coupled signal transduction.
Subjects: Medicine and Health.