Genus Simplexvirus: Life cycle

The two same-name members of the subfamily Alphaherpesvirinae, the human herpesviruses Herpes simplex virus-1 (HSV-1) and Herpes simplex virus-2 (HSV-2), use human epithelial cells to establish their lytic phase, and neuronal cells to establish a lysogenic (latent) phase. Once the herpes simplex virus has infected the target cell, the viral genome enters the nucleus, where it is transcribed in a specific sequence: immediate-early (IE), early (E), and late viral genes (L). This cascade of gene expression, which largely determines viral genome transcription, is strictly initiated by the tegument protein VP16. Immediately af¬ter the virus is endocytosed through the host cell membrane, VP16 is released by the virions and together with two cell factors, HCF-1 and Oct-1, forms a transcriptional regulatory complex that aims to initiate the transcription of IE genes.