Herpes simplex virus protein UL12.5 (UL12.5)

Herpes simplex virus protein UL12.5 (UL12.5) is a viral protein that serves as a critical molecular trigger for the reactivation of herpes simplex virus (HSV-1 and HSV-2) from latency in the nervous system. Identified as a truncated isoform of the UL12 alkaline nuclease, UL12.5 does not primarily function in DNA replication but instead highjacks host neuronal sensing pathways to initiate the transition from dormancy to lytic infection. By detecting cellular stress signals—such as those from fever, UV exposure, or concurrent infections—UL12.5 activates the viral replication machinery, leading to recurrent outbreaks of cold sores or genital herpes. As the first viral protein identified to be essential for the reactivation process, it has emerged as a promising therapeutic target for preventing viral flare-ups. Current drug development efforts are focused on identifying small-molecule inhibitors that can block UL12.5 function, potentially maintaining the virus in a permanent latent state and reducing the risk of transmission and associated complications like encephalitis or Alzheimer's disease.

Other names

UL12.5HSV reactivation triggerViral alkaline nuclease isoform UL12.5

Inhibition of UL12.5 function prevents the virus from sensing cellular stress signals and initiating the transition from latency to lytic replication.