The use of vesicular stomatitis virus pseudotype production in the study of a temperature-sensitive murine leukemia virus

Abstract

A mutant of Moloney murine leukemia virus (MoLV), designated ts 3 was recently shown to have a temperature-sensitive defect associated with the release of mature virus particles budding from the cell membrane [Wong, P. K. Y., and McCarter, J. A., Virology 58, 396–408 (1974)] . In an attempt to determine whether the defective function resides in an envelope component of the virion, the formation of pseudotypes between VSV and ts 3 was studied under nonpermissive and permissive conditions of ts 3 infection. Whereas similar levels of phenotypic mixing were observed between VSV and wild-type MoLV at both 39 and 34°, the level of pseudotypes formed between VSV and ts 3 was found to be considerably lower at 39° (nonpermissive temperature) than at 34° (permissive temperature). The results of temperature-shift experiments indicate that two separate blocks to VSV ts 3 pseudotype production may occur depending on the length of time ts 3-infected cells are incubated at the nonpermissive temperature. Preincubation of ts 3-infected cells for 24 hr at 39°, prior to superinfection with VSV at 39°, prevents pseudotype formation. In contrast, brief incubation at 39°C, coincident with VSV infection, introduces a reversible block on the release of VSV (ts 3) pseudotypes from the cell membrane. Complementation of ts 3 through ts 3 (VSV) pseudotype production was not detected at the nonpermissive temperature.