UMMS Affiliation

Program in Molecular Medicine

Date

3-21-2017

Document Type

Article

Disciplines

Biochemistry, Biophysics, and Structural Biology | Cell and Developmental Biology | Genetics and Genomics

Abstract

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.

Rights and Permissions

Copyright © 2017, Azmi et al.

DOI of Published Version

10.7554/eLife.22512

Source

Elife. 2017 Mar 21;6. pii: e22512. doi: 10.7554/eLife.22512. Link to article on publisher's site

Related Resources

Link to Article in PubMed

Keywords

DNA Replication, eukaryotic, helicase, S. cerevisiae, biochemistry, chromatin remodeling enzyme, chromosomes, genes, nucleosome, origin licensing

Journal Title

eLife

PubMed ID

28322723

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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