G-Quadruplexes and DNA Replication Origins.

DNA replication ensures the accurate duplication of the genome at each cell cycle. During S phase, tens of thousands of replication origins throughout the vertebrate genome are activated according to a spatiotemporal program. The genome-wide mapping of origins in several model systems has identified G-quadruplexes-higher-order DNA structures formed from G-rich sequences-as potential key regulators of origin activity. Here, I describe genetic experiments demonstrating the role of G-quadruplexes in origin function. I discuss the different means by which G-quadruplexes might regulate origin function. Finally, comparisons of replicon organization in the three domains of life suggest that G-quadruplexes may have retained a conserved role in origin function during evolution.