Analysis of a temperature-sensitive mutation affecting the integration protein of Moloney murine leukemia virus.

We have previously described a series of mutations in the 3' terminus of the pol gene of Moloney murine leukemia virus which adversely affect the establishment of an integrated provirus (Roth, M. J., Schwartzberg, P., Tanese, N., and Goff, S. P., J. Virol. 64, 4709-4717, 1990). While most of the mutations were unconditionally lethal for virus replication, we now demonstrate that one mutation, in6161-12, a 12-base pair linker insertion into the 3' end of the pol gene, causes a temperature-sensitive phenotype. This mutant virus is temperature-sensitive for IN protein function as well as viral replication.