EMD-17202
Cryo-EM density map of the C. elegans complex CMG helicase/TIM-1/TIPN-1/DNSN-1 dimer on fork DNA (Multi-body Refinement MCM-2-7 NTDs)
EMD-17202
Single-particle3.2 Å
Deposition: 25/04/2023Map released: 16/08/2023
Last modified: 04/10/2023
Sample Organism:
Caenorhabditis elegans
Sample: In vitro reconstituted complex of Caenorhabditis elegans CMG helicase bound by TIM-1/TIPN-1 and a homodimer of DNSN-1, on a synthetic forked DNA substrate
Deposition Authors: Jenkyn-Bedford M
,
Yeeles JTP
Sample: In vitro reconstituted complex of Caenorhabditis elegans CMG helicase bound by TIM-1/TIPN-1 and a homodimer of DNSN-1, on a synthetic forked DNA substrate
Deposition Authors: Jenkyn-Bedford M
,
Yeeles JTP
DNSN-1 recruits GINS for CMG helicase assembly during DNA replication initiation in Caenorhabditis elegans.
Xia Y ,
Sonneville R,
Jenkyn-Bedford M ,
Ji L,
Alabert C ,
Hong Y ,
Yeeles JTP ,
Labib KPM
(2023) Science , 381 , eadi4932 - eadi4932
,
Sonneville R,
Jenkyn-Bedford M ,
Ji L,
Alabert C ,
Hong Y ,
Yeeles JTP ,
Labib KPM
(2023) Science , 381 , eadi4932 - eadi4932
Abstract:
Assembly of the CMG (CDC-45-MCM-2-7-GINS) helicase is the key regulated step during eukaryotic DNA replication initiation. Until now, it was unclear whether metazoa require additional factors that are not present in yeast. In this work, we show that Caenorhabditis elegans DNSN-1, the ortholog of human DONSON, functions during helicase assembly in a complex with MUS-101/TOPBP1. DNSN-1 is required to recruit the GINS complex to chromatin, and a cryo-electron microscopy structure indicates that DNSN-1 positions GINS on the MCM-2-7 helicase motor (comprising the six MCM-2 to MCM-7 proteins), by direct binding of DNSN-1 to GINS and MCM-3, using interfaces that we show are important for initiation and essential for viability. These findings identify DNSN-1 as a missing link in our understanding of DNA replication initiation, suggesting that initiation defects underlie the human disease syndrome that results from DONSON mutations.
Assembly of the CMG (CDC-45-MCM-2-7-GINS) helicase is the key regulated step during eukaryotic DNA replication initiation. Until now, it was unclear whether metazoa require additional factors that are not present in yeast. In this work, we show that Caenorhabditis elegans DNSN-1, the ortholog of human DONSON, functions during helicase assembly in a complex with MUS-101/TOPBP1. DNSN-1 is required to recruit the GINS complex to chromatin, and a cryo-electron microscopy structure indicates that DNSN-1 positions GINS on the MCM-2-7 helicase motor (comprising the six MCM-2 to MCM-7 proteins), by direct binding of DNSN-1 to GINS and MCM-3, using interfaces that we show are important for initiation and essential for viability. These findings identify DNSN-1 as a missing link in our understanding of DNA replication initiation, suggesting that initiation defects underlie the human disease syndrome that results from DONSON mutations.