In situ processing of a retroviral nucleocapsid protein by the viral proteinase.

The proteolytic processing pathway of the nucleocapsid protein (NC) by the viral proteinase within intact capsids of equine infectious anemia virus (EIAV) is presented. The cleavage sites are located at the carboxyl side of the first cysteine residue within the zinc-finger domains. EIAV is used as a model to predict similar NC cleavages in other retroviruses, including human immunodeficiency virus (HIV). The observed cleavages suggest a previously unrecognized function of the retroviral proteinase that may be crucial for replication during the early stages of the virus life-cycle (i.e. reverse transcription/integration).