Detangling knots: the intricate roles of G-quadruplexes in herpesvirus replication.

The Herpesviridae family comprises complex, double-stranded DNA viruses capable of infecting a variety of hosts, including humans. Human herpesviruses, grouped into three subfamilies (alpha, beta, and gamma), establish lifelong, latent infections in most of the global population. Despite widespread prevalence and the ability to cause disease upon reactivation, no cure exists, and current antivirals fail to eliminate latent infections. Therefore, a better understanding of herpesvirus biology is essential for therapeutic development. Recent studies highlight the importance of non-canonical nucleic acid structures, such as G-quadruplexes (G4s), in modulating herpesvirus lytic and latent infection mechanisms. Interestingly, herpesvirus genomes encode an unusually high number of putative G-quadruplex (PG4) forming sequences compared to other viruses. Although G4 biology has been studied for over two decades-initially in human systems-their dynamic nature in cells complicates mechanistic understanding and therapeutic targeting. Herein, we describe the nuances associated with working with G4s at the cellular level, the known and conserved roles of G4s across human herpesviruses, and what is needed to move the field forward. As the technology used to study G4s advances, so will our understanding of how these unique biological structures contribute to herpesvirus replication, potentially paving the way for novel antivirals, and beyond.