Eukaryotic DNA replication is regulated to ensure all chromosomes replicate once and only once per cell cycle. … Cell cycle regulation by protein phosphorylation ensures that pre-RC assembly can only occur in G1 phase, whereas helicase activation and loading can only occur in S phase.

How is replication initiation regulated in prokaryotes and in eukaryotes?

The initiation of chromosomal replication occurs only once during the cell cycle in both prokaryotes and eukaryotes. … Bacterial chromosome replication is initiated at a single origin, oriC , by the initiator protein DnaA, which specifically interacts with 9-bp nonpalindromic sequences (DnaA boxes) at oriC .

How is the eukaryotic cell cycle regulated?

The eukaryotic cell cycle is intricately controlled, primarily by several protein kinases, which phosphorylate other regulatory factors, such as the anaphase promoting complex (APC), and each other 1, 2. The cyclin-dependent kinases (CDKs) are thought to be the cornerstone of cell cycle control.