PASSAGE THROUGH MITOSIS IS REQUIRED FOR ONCORETROVIRUSES BUT NOT FOR THE HUMAN-IMMUNODEFICIENCY-VIRUS

The human immunodeficiency virus productively infects and integrates i nto cells that have been arrested in the cell cycle with either gamma irradiation or aphidicolin. Integration by oncoretroviruses such as th e murine leukemia virus (MuLV), on the other hand, depends on cell pro liferation. Although the entire cell cycle is not necessary for MuLV i nfection, it is essential that the infected cells pass through mitosis . The long terminal repeat circle junction, a marker for nuclear entry , is first observed in MuLV-infected cells immediately after mitosis. These results suggest that mitosis is necessary for nuclear entry of M uLV, but not human immunodeficiency virus, unintegrated proviral DNA.