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

• 成果类型: Article
• 署名作者: Xia, Yisui; Sonneville, Remi; Jenkyn-Bedford, Michael; Ji, Liqin; Alabert, Constance; Hong, Ye; Yeeles, Joseph T. P.; Labib, Karim P. M.
• 署名单位: University of Dundee; MRC Laboratory Molecular Biology; Shandong University; University of Dundee; Shenzhen University; Rockefeller University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12293
• DOI: 10.1126/science.adi4932
• 发表日期: 2023-09-22
• 页码: 1302-+
• 关键词: cryo-em; pol-epsilon; complex; fork; sld3; phosphorylation; binding; Visualization; activation; mechanisms

摘要

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.