Figure 1.

Replication cycle of HIV: graphical depiction of the major events of the HIV replication cycle. Viral entry is mediated by binding of Env to CD4 and a co-receptor (CXCR4 or CCR5). After the viral membrane fuses with the plasma membrane the capsid and RNA genome are transported into the nucleus. The viral genome is reversed transcribed by Pol and integrates into the host genome. The host RNA polymerase transcribes RNA copies of the genome, which are exported in an unspliced form to produce Gag and Gag–Pol or various spliced forms to produce the other viral proteins. Unspliced RNA genomes are also packaged into newly formed virions. Most viral protein translation occurs in the cytoplasm, but Env gp160 is translated into the lumen of the rough ER and transported through the secretory pathway, where it is glycosylated and cleaved by furin into gp120 and gp41.