HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 2-LTR CIRCLES RESIDE IN A NUCLEOPROTEIN COMPLEX WHICH IS DIFFERENT FROM THE PREINTEGRATION COMPLEX

The preintegration complex of human immunodeficiency virus type 1 (HIV -1) is a large nucleoprotein complex containing viral nucleic acids in association with products of the viral gag and pol genes. One of thes e proteins, integrase, is absolutely required for the integration and formation of the provirus. Although HIV-1-specific 2-LTR circles from nuclei of HIV-1-infected cells were found to be associated within a hi gh-molecular-weight nucleoprotein complex, antibodies to HIV-1 integra se failed to precipitate this form of viral DNA. This result indicates that circular forms of HIV-1 DNA are not associated with integrase. T hese viral DNA forms seem to exist in a context of a nucleoprotein com plex that is different from a preintegration complex of HIV-1.