HIV-1

HIV-1 is a retrovirus whose replication relies on reverse transcription of viral RNA into DNA, integrating into host genomes to produce progeny virions^[1]. Viral entry is mediated by interactions between the envelope glycoprotein gp120 and the host CD4 receptor, along with chemokine co-receptors CXCR4 or CCR5, triggering membrane fusion and infection of target cells^[2][3]. Post-entry, reverse transcription and integration involve complex protein-nucleic acid interactions, with viral integrase and nucleocapsid proteins directing efficient DNA synthesis^[4]. The viral replication cycle engages host signaling pathways, including calcium-dependent activation cascades, nitric oxide signaling, and protein kinase C isoforms, which modulate viral transcription and assembly^[5][6]. HIV-1 accessory proteins, such as Nef and Vif, interact with host factors to enhance replication and evade immune detection, establishing persistent infection^[7]. Compared with related retroviruses, HIV-1 exhibits unique isoform-specific interactions of its envelope and regulatory proteins with host pathways, enabling differential cellular tropism and pathogenicity^[1]. Small molecule inhibitors and peptide agonists targeting gp120-CD4 binding, integrase activity, or host signaling components have been employed to dissect viral replication mechanisms in vitro and in vivo, providing tools for experimental modulation of viral processes^[8][9]. Mechanistically, selective modulation of these pathways has been used to evaluate antiviral efficacy and to define host determinants of infection, highlighting the functional distinctions among viral isoforms and their cellular interactions^[10][11].