Nucleosomes influence multiple steps during replication initiation.

Published online

Journal Article

Eukaryotic replication origin licensing, activation and timing are influenced by chromatin but a mechanistic understanding is lacking. Using reconstituted nucleosomal DNA replication assays, we assessed the impact of nucleosomes on replication initiation. To generate distinct nucleosomal landscapes, different chromatin-remodeling enzymes (CREs) were used to remodel nucleosomes on origin-DNA templates. Nucleosomal organization influenced two steps of replication initiation: origin licensing and helicase activation. Origin licensing assays showed that local nucleosome positioning enhanced origin specificity and modulated helicase loading by influencing ORC DNA binding. Interestingly, SWI/SNF- and RSC-remodeled nucleosomes were permissive for origin licensing but showed reduced helicase activation. Specific CREs rescued replication of these templates if added prior to helicase activation, indicating a permissive chromatin state must be established during origin licensing to allow efficient origin activation. Our studies show nucleosomes directly modulate origin licensing and activation through distinct mechanisms and provide insights into the regulation of replication initiation by chromatin.

Full Text

Duke Authors

Cited Authors

  • Azmi, IF; Watanabe, S; Maloney, MF; Kang, S; Belsky, JA; MacAlpine, DM; Peterson, CL; Bell, SP

Published Date

  • March 21, 2017

Published In

Volume / Issue

  • 6 /

PubMed ID

  • 28322723

Pubmed Central ID

  • 28322723

Electronic International Standard Serial Number (EISSN)

  • 2050-084X

Digital Object Identifier (DOI)

  • 10.7554/eLife.22512

Language

  • eng

Conference Location

  • England