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Title: Single-molecule imaging reveals the mechanism of bidirectional replication initiation in metazoa
Metazoan genomes are copied bidirectionally from thousands of replication origins. Replication initiation entails the assembly and activation of two CMG helicases (Cdc45⋅Mcm2-7⋅GINS) at each origin. This requires several replication firing factors (including TopBP1, RecQL4, and DONSON) whose exact roles are still under debate. How two helicases are correctly assembled and activated at each origin is a long-standing question. By visualizing the recruitment of GINS, Cdc45, TopBP1, RecQL4, and DONSON in real time, we uncovered that replication initiation is surprisingly dynamic. First, TopBP1 transiently binds to the origin and dissociates before the start of DNA synthesis. Second, two Cdc45 are recruited together, even though Cdc45 alone cannot dimerize. Next, two copies of DONSON and two GINS simultaneously arrive at the origin, completing the assembly of two CMG helicases. Finally, RecQL4 is recruited to the CMG⋅DONSON⋅DONSON⋅CMG complex and promotes DONSON dissociation and CMG activation via its ATPase activity.  more » « less
Award ID(s):
2144481
PAR ID:
10570366
Author(s) / Creator(s):
; ; ; ;
Corporate Creator(s):
Editor(s):
Behie, Scott
Publisher / Repository:
Elsevier, Cell
Date Published:
Journal Name:
Cell
Volume:
187
Issue:
15
ISSN:
0092-8674
Page Range / eLocation ID:
3992 to 4009.e25
Subject(s) / Keyword(s):
Cdc45 DONSON GINS KEHRMIT RecQL4 TopBP1 origin firing replication initiation
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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