DNSN-1 recruits GINS for CMG helicase assembly during DNA replication initiation in C. elegans

Assembly of the DNA helicase known as CMG (CDC45-MCM-GINS) is the key regulated step during DNA replication initiation in eukaryotes. Using the Caenorhabditis elegans embryo as a model system, we identify a new CMG assembly factor called DNSN-1, which associates with the BRCT-domain protein MUS-101. We show that DNSN-1 is required to recruit the GINS complex to chromatin and find that DNSN-1 positions GINS on the MCM-2-7 helicase motor, by direct binding of DNSN-1 to GINS and MCM-3, on interfaces that are important for initiation and essential for viability.