Nucleosome breathing and remodeling constrain CRISPR‐Cas9 function
The CRISPR-Cas9 bacterial surveillance system has become a versatile tool for genome editing and gene regulation in eukaryotic cells, yet how CRISPR-Cas9 contends with the barriers presented by eukaryotic chromatin is poorly understood. Here we investigate how the smallest unit of chromatin, a nucleosome, constrains the activity of the CRISPR-Cas9 system. We find that nucleosomes assembled on native DNA sequences are permissive to Cas9 action. However, the accessibility of nucleosomal DNA to Cas9 is variable over several orders of magnitude depending on dynamic properties of the DNA sequence and the distance of the PAM site from the nucleosome dyad. We further find that chromatin remodeling enzymes stimulate Cas9 activity on nucleosomal templates. Our findings imply that the spontaneous breathing of nucleosomal DNA together with the action of chromatin remodelers allows Cas9 to effectively act on chromatin in vivo.
Article and author information
- Karen Adelman, National Institute of Environmental Health Sciences, United States
- Received: December 2, 2015
- Accepted: April 16, 2016
- Accepted Manuscript published: April 28, 2016 (version 1)
- Version of Record published: May 25, 2016 (version 2)
© 2016, Isaac et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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