High-Speed Atomic Force Microscopy Reveals Spatiotemporal Dynamics of Histone Protein H2A Involution by DNA Inchworming

J Phys Chem Lett. 2021 Apr 22;12(15):3837-3846. doi: 10.1021/acs.jpclett.1c00697. Epub 2021 Apr 14.

Abstract

DNA-histone interaction is always perturbed by epigenetic regulators to regulate gene expression. Direct visualization of this interaction is yet to be achieved. By using high-speed atomic force microscopy (HS-AFM), we have observed the dynamic DNA-histone H2A interaction. HS-AFM movies demonstrate the globular core and disordered tail of H2A. DNA-H2A formed the classic "beads-on-string" conformation on poly-l-lysine (PLL) and lipid substrates. Notably, a short-linearized double-stranded DNA (dsDNA), resembling an inchworm, wrapped around a single H2A protein only observed on the lipid substrate. Such a phenomenon does not occur for plasmid DNA or linearized long dsDNA on the same substrate. Strong adsorption of PLL substrate resulted in poor dynamic DNA-H2A interaction. Nonetheless, short-linearized dsDNA-H2A formed stable wrapping with a "diamond ring" topology on the PLL substrate. Reversible liquid-liquid phase separation (LLPS) of the DNA-H2A aggregate was visualized by manipulating salt concentrations. Collectively, our study suggest that HS-AFM is feasible for investigating epigenetically modified DNA-histone interactions.

MeSH terms

  • DNA / chemistry*
  • Histone Chaperones / chemistry*
  • Histones / chemistry
  • Microscopy, Atomic Force

Substances

  • Histone Chaperones
  • Histones
  • DNA