Viral fusion and entry requires the binding of glycoprotein gp120 to CD4
receptors at the cell surface as well as to CC chemokine receptor type 5 (CCR5) or CXC chemokine receptor type 4
(CXCR4). The viral nucleocapsid enters the cytoplasm and uses cytoplasmic dynein to move toward the nuclear pore
complex (NPC). The viral RNA is retrotranscribed into proviral double‑stranded cDNA (dscDNA), which can stay in the
cytosol, where it is highly unstable and exists in a transient, reversible pre‑integration latent state, or can form a
pre‑integration complex consisting of dscDNA, viral proteins and some host cell proteins. When ATP levels are adequate,
the pre‑integration complex is transported into the nucleus through the NPC, and the dscDNA either circularizes as one or
two long terminal repeat‑containing circles or is integrated into a host cell chromosome. After integration, the provirus
remains quiescent, existing in a permanent post‑integration latent state. On activation, the viral genome is transcribed by
the synergic interaction of cellular transcription factors (nuclear factor‑κB (NF‑κB), nuclear factor of activated T cells (NFAT)
and specificity protein 1 ( SP1)) and the viral transactivator, Tat. Rev, a viral protein, regulates the splicing and cytosolic
transport of some of the viral mRNAs, which are translated into regulatory and structural viral proteins. New virions
assemble and bud through the cell membrane, maturing through the activity of the viral protease.
Nature Reviews | Microbiology