The MCM2-7 helicase complex is loaded on DNA replication origins during the G1 
phase of the cell cycle to license the origins for replication in S phase. How 
the initiator primase-polymerase complex, DNA polymerase alpha (pol alpha), is 
brought to the origins is still unclear. We show that And-1/Ctf4 (Chromosome 
transmission fidelity 4) interacts with Mcm10, which associates with MCM2-7, and 
with the p180 subunit of DNA pol alpha. And-1 is essential for DNA synthesis and 
the stability of p180 in mammalian cells. In Xenopus egg extracts And-1 is 
loaded on the chromatin after Mcm10, concurrently with DNA pol alpha, and is 
required for efficient DNA synthesis. Mcm10 is required for chromatin loading of 
And-1 and an antibody that disrupts the Mcm10-And-1 interaction interferes with 
the loading of And-1 and of pol alpha, inhibiting DNA synthesis. And-1/Ctf4 is 
therefore a new replication initiation factor that brings together the MCM2-7 
helicase and the DNA pol alpha-primase complex, analogous to the linker between 
helicase and primase or helicase and polymerase that is seen in the bacterial 
replication machinery. The discovery also adds to the connection between 
replication initiation and sister chromatid cohesion.