RT Journal Article
SR Electronic
T1 A new class of disordered elements controls DNA replication through initiator self-assembly
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 623058
DO 10.1101/623058
A1 Matthew W. Parker
A1 Maren Bell
A1 Mustafa Mir
A1 Jonchee A. Kao
A1 Xavier Darzacq
A1 Michael R. Botchan
A1 James M. Berger
YR 2019
UL http://biorxiv.org/content/early/2019/04/29/623058.abstract
AB The initiation of DNA replication in metazoans occurs at thousands of chromosomal sites known as origins. At each origin, the Origin Recognition Complex (ORC), Cdc6, and Cdt1 co-assemble to load the Mcm2-7 replicative helicase onto chromatin. Current replication models envisage a linear arrangement of isolated origins functioning autonomously; the extent of inter-origin organization and communication is unknown. Here, we report that the replication initiation machinery of D. melanogaster unexpectedly undergoes liquid-liquid phase separation (LLPS) upon binding DNA in vitro. We find that ORC, Cdc6, and Cdt1 contain intrinsically disordered regions (IDRs) that drive LLPS and constitute a new class of phase separating elements. Initiator IDRs are shown to regulate multiple functions, including chromosome recruitment, initiator-specific co-assembly, and Mcm2-7 loading. These data help explain how CDK activity controls replication initiation and suggest that replication programs are subject to higher-order levels of inter-origin organization.