The Involvement of Acidic Nucleoplasmic DNA-binding Protein (And-1) in the Regulation of Prereplicative Complex (pre-RC) Assembly in Human Cells

DNA replication in all eukaryotes starts with the process of loading the replicative helicase MCM2–7 onto chromatin during late mitosis of the cell cycle. MCM2–7 is a key component of the prereplicative complex (pre-RC), which is loaded onto chromatin by the concerted action of origin recognition complex, Cdc6, and Cdt1. Here, we demonstrate that And-1 is assembled onto chromatin in late mitosis and early G1 phase before the assembly of pre-RC in human cells. And-1 forms complexes with MCM2–7 to facilitate the assembly of MCM2–7 onto chromatin at replication origins in late mitosis and G1 phase. We also present data to show that depletion of And-1 significantly reduces the interaction between Cdt1 and MCM7 in G1 phase cells. Thus, human And-1 facilitates loading of the MCM2–7 helicase onto chromatin during the assembly of pre-RC. Background: The assembly of a replicative helicase MCM2–7 onto replication origins is essential for initiation of DNA replication. Results: And-1 facilitates assembly of MCM2–7 onto replication origins. Conclusion: And-1 is proposed to be a critical regulator of prereplicative complex assembly in human cells. Significance: These studies reveal a novel role for human And-1 in the licensing of replication origins.