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

CpG methylation increases DNA stiffness, weakens nucleosome wrapping, and enhances chromatin condensate density, promoting heterochromatin organization across multiple scales.

• Why it matters: Understanding how DNA methylation influences chromatin structure beyond protein recruitment is crucial for revealing mechanisms of gene regulation and heterochromatin formation.
• What they did: Using single-molecule force spectroscopy, FRAP, and nanorheology, the study examined the effects of CpG methylation on DNA mechanics, nucleosome stability, and chromatin condensate properties across different scales.
• The result: Methylation-induced changes lead to denser, more viscoelastic chromatin condensates that facilitate heterochromatin formation, primarily through modifications in physical properties rather than direct protein recognition.