Coordinated initiation of DNA replication is essential to ensure efficient and timely DNA synthesis. Yet the molecular determinants that confer origin selectivity in mammalian cells remain incompletely defined. Herein, we present data demonstrating a pivotal role for RNAs transcribed in the proximity of actively replicating gene loci. We show that RNAs aNChoring ORC1 (ANCORs) to the histone variant H2A.Z facilitate origin firing during DNA replication. This ANCOR-H2A.Z interaction appears to be essential for cells to duplicate their genetic material. Widespread and locus-specific perturbations of these transcripts correlate with anomalous replication patterns and a notable loss of the H2A.Z replicative marker at the origin site. Collectively, we present a previously undescribed RNA-mediated mechanism that is associated with the generation of active replication origins in mammalian cells. Our findings delineate a strategy to modulate the origins of replication in human cells at a local and global level, with potentially broad biomedical implications.
