Visualization of the three-dimensional structure of the human centromere in mitotic chromosomes by superresolution microscopy

Mol Biol Cell. 2023 May 15;34(6):ar61. doi: 10.1091/mbc.E22-08-0332. Epub 2023 Mar 22.

Abstract

The human centromere comprises large arrays of repetitive α-satellite DNA at the primary constriction of mitotic chromosomes. In addition, centromeres are epigenetically specified by the centromere-specific histone H3 variant CENP-A that supports kinetochore assembly to enable chromosome segregation. Because CENP-A is bound to only a fraction of the α-satellite elements within the megabase-sized centromere DNA, correlating the three-dimensional (3D) organization of α-satellite DNA and CENP-A remains elusive. To visualize centromere organization within a single chromatid, we used a combination of the centromere chromosome orientation fluorescence in situ hybridization (Cen-CO-FISH) technique together with structured illumination microscopy. Cen-CO-FISH allows the differential labeling of the sister chromatids without the denaturation step used in conventional FISH that may affect DNA structure. Our data indicate that α-satellite DNA is arranged in a ring-like organization within prometaphase chromosomes, in the presence or absence of spindle's microtubules. Using expansion microscopy, we found that CENP-A organization within mitotic chromosomes follows a rounded pattern similar to that of α-satellite DNA, often visible as a ring thicker at the outer surface oriented toward the kinetochore-microtubule interface. Collectively, our data provide a 3D reconstruction of α-satellite DNA along with CENP-A clusters that outlines the overall architecture of the mitotic centromere.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantigens / metabolism
  • Centromere / metabolism
  • Centromere Protein A / metabolism
  • Chromosomal Proteins, Non-Histone / metabolism
  • DNA
  • DNA, Satellite*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Microscopy*

Substances

  • DNA, Satellite
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone
  • Autoantigens
  • DNA