Chromatin mechanics and regulatory protein function: insights from single-molecule force spectroscopy

Single-molecule force spectroscopy probes chromatin mechanics by resolving force-induced conformational transitions across multiple length scales. Recent studies extend these measurements beyond canonical nucleosomes to chromatin assembled on native genomic DNA, incorporating histone variants, post-translational modifications, and specialized chromatin architectures. These approaches further scale to chromatosomes, folded fibers, and intact chromosomes, demonstrating that chromatin composition and organization modulate mechanical properties across multiple length scales. Single-molecule measurements further demonstrate that regulatory proteins, including transcription factors, architectural proteins, and chromatin-associated cofactors, actively sense and reshape this mechanical landscape. Together, these observations support a unified view of chromatin as a mechanically encoded medium that can be both written and read.