Involvement of HIV-I nucleocapsid protein in the recruitment of reverse transcriptase into nucleoprotein complexes formed in vitro.

Retroviral reverse transcription takes place within the virion core, where nucleocapsid (NC) protein (NCp) molecules cover the dimeric RNA genome. NCp thus has structural roles in the virion core but is also extensively involved in viral DNA synthesis and virion assembly. To further characterize the role of human immunodeficiency virus type 1 NCp7 during replication of the viral genome, we investigated the relationship between NCp7 and reverse transcriptase (RT) either directly or within nucleoprotein complexes in vitro. We show that NCp7 interacts directly with RT and enhances synthesis of full-length cDNA by increasing RT processivity. Using NCp7 mutants, we show that the complete amino acid sequence of NCp7 is required for functional interactions with RT. Our results suggest that NCp7 plays a role in recruitment of RT into stable and functional nucleoprotein complexes during viral DNA synthesis.