Multiscale physical effects of CpG methylation on DNA mechanics, nucleosome wrapping, and chromatin condensates.

CpG methylation modulates DNA mechanics and chromatin organization by increasing DNA stiffness, weakening nucleosome wrapping, and promoting heterochromatin condensates.

• Why it matters: Understanding how DNA methylation influences chromatin structure beyond protein recruitment is crucial for elucidating epigenetic regulation mechanisms and heterochromatin formation.
• What they did: The study used single-molecule force spectroscopy, FRAP, and nanorheology to analyze the effects of CpG methylation on DNA, nucleosomes, and chromatin condensates across multiple scales, involving several experimental approaches.
• The result: Findings reveal that CpG methylation enhances DNA rigidity, destabilizes nucleosome wrapping, and, together with H3K9me3, promotes HP1α-mediated chromatin condensation, shaping heterochromatin architecture.