CHARACTERIZATION OF HIV REPLICATION COMPLEXES EARLY AFTER CELL-TO-CELL INFECTION

In this study, we have characterized the HIV DNA-containing replicatio n complexes present in cells early after cell-to-cell infection, using sucrose gradient sedimentation and immunoprecipitation. Six hours aft er cell-to-cell infection, a cytoplasmic HIV replication complex sedim ented as a large structure (320S). This replication complex was precip itated by antisera to three virus-coded enzymes (reverse transcriptase , integrase, protease), to the matrix protein (p17), and to cellular h istones but not to the major capsid protein (p24). This replication co mplex was not associated with cell membranes and could not be dissocia ted into smaller discrete subunits, using detergents. Nuclear extracts from the same cell-to-cell infection contained a smaller (80S) comple x that lacked reverse transcriptase and matrix protein (p17). Cytoplas mic replication complexes from a cell-free virus infection sedimented as 160S structures under identical conditions, as previously reported. Our results indicate that, following cell-to-cell transmission of HIV , all the HIV pol gene products, the matrix protein p17, and cellular histones are present in cytoplasmic replication complexes that are tak ing part in or have completed reverse transcription. Transportation of the cytoplasmic replication complex to the nucleus is associated with structural changes, including a reduction in size and altered protein composition.