Cytosine Methylation Enhances DNA Condensation Revealed by Equilibrium Measurements Using Magnetic Tweezers

• DOI: 10.1021/jacs.9b11957
• Publication Date: 2020-04-24T19:32:15Z
• Authors: Ya-Jun Yang; Hai-Long Dong; Xiao-Wei Qiang; Hang Fu; Er-Chi Zhou; Chen Zhang; Lei Yin; Xue-Feng Chen; Fu-Chao Jia; Liang Dai; Zhi-Jie Tan; Xing-Hua Zhang
• Keywords: CpG site; DNA condensation; Epigenomics

CpG methylation of DNA is common in mammalian cells. In sperm, the has highest level and condensed into toroidal structures. How affects structures interactions important to understand its biological roles but largely unknown. Using an RNA–DNA–RNA structure, we observed equilibrium hopping dynamics between extended states presence polyamines or polylysine peptide as a reduced model histone tails. Combing with measured elasticities, report that each cytosine nucleotide substantially increases DNA–DNA attraction by up 0.2 kBT. For 57% GC content, relative increase caused 32% for spermine-induced 9% polylysine-induced attraction. These findings help us evaluate energetic contributions sperm development chromatin regulation.