Dynamics of nucleosomes and chromatin fibers revealed by single-molecule measurements

BMB Rep. 2025 Jan;58(1):24-32. doi: 10.5483/BMBRep.2024-0191.

Abstract

The nucleosome is the fundamental structural unit of chromosome fibers. DNA wraps around a histone octamer to form a nucleosome while neighboring nucleosomes interact to form higher-order structures and fit gigabase-long DNAs into a small volume of the nucleus. Nucleosomes interrupt the access of transcription factors to a genomic region and provide regulatory controls of gene expression. Biochemical and physical cues stimulate wrapping-unwrapping and condensation-decondensation dynamics of nucleosomes and nucleosome arrays. Nucleosome dynamics and chromatin fiber organization are influenced by changes in the ionic background within the nucleus, post-translational modifications of histone proteins, and DNA sequence characteristics, such as histone-binding motifs and nucleosome spacing. Biochemical and biophysical measurements, along with in silico simulations, have been extensively used to study the regulatory effects on chromatin dynamics. In particular, single-molecule measurements have revealed novel mechanistic details of nucleosome and chromatin dynamics. This minireview elucidates recent findings on chromatin dynamics from these approaches. [BMB Reports 2025; 58(1): 24-32].

Publication types

  • Review

MeSH terms

  • Animals
  • Chromatin Assembly and Disassembly / physiology
  • Chromatin* / metabolism
  • DNA / chemistry
  • DNA / metabolism
  • Histones* / metabolism
  • Humans
  • Nucleosomes* / metabolism
  • Single Molecule Imaging / methods

Substances

  • Nucleosomes
  • Chromatin
  • Histones
  • DNA