Figure 3.

Nuclear organization of replication origins. Genome organization of replication domains in (a) mammalian and (b) yeast. In both models, early replicating domains are clustered in the center region while late replicating domains are at peripheral region. (a) In metazoans, early replication domains are gene-rich, GC-rich, and enriched with regulatory elements like promoters and enhancers, the TAD boundary is insulated by CTCF. Late replicating domains are AT-rich and gene-poor. (b) In yeast, early replicating domains are mediated mainly by Fkh1/2, the late replicating domains are located at telomeric regions and mediated by Rif1.