Asymmetric unwrapping of nucleosomes under tension directed by DNA local flexibility.
Cell
; 160(6): 1135-44, 2015 Mar 12.
Article
in En
| MEDLINE
| ID: mdl-25768909
ABSTRACT
Dynamics of the nucleosome and exposure of nucleosomal DNA play key roles in many nuclear processes, but local dynamics of the nucleosome and its modulation by DNA sequence are poorly understood. Using single-molecule assays, we observed that the nucleosome can unwrap asymmetrically and directionally under force. The relative DNA flexibility of the inner quarters of nucleosomal DNA controls the unwrapping direction such that the nucleosome unwraps from the stiffer side. If the DNA flexibility is similar on two sides, it stochastically unwraps from either side. The two ends of the nucleosome are orchestrated such that the opening of one end helps to stabilize the other end, providing a mechanism to amplify even small differences in flexibility to a large asymmetry in nucleosome stability. Our discovery of DNA flexibility as a critical factor for nucleosome dynamics and mechanical stability suggests a novel mechanism of gene regulation by DNA sequence and modifications.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA
/
Nucleosomes
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Cell
Year:
2015
Type:
Article
Affiliation country:
United States