Vertebrate centromeres in mitosis are functionally bipartite structures stabilized by cohesin

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• Centromeres are essential for chromosome segregation during cell division.
• The 3D structure of vertebrate centromeres and its role in kinetochore assembly remain poorly understood.

Purpose of the Study:

• To elucidate the three-dimensional organization of vertebrate centromeres during mitosis.
• To investigate how this structure ensures faithful chromosome segregation.

Main Methods:

• Super-resolution imaging
• Capture-C technology
• Polymer modeling
• Electron tomography

Main Results:

• Vertebrate centromeres are partitioned into two subdomains by condensins during mitosis.
• This bipartite structure is conserved across human, mouse, and chicken cells.
• Bipartite centromeres assemble bipartite kinetochores that bind distinct microtubule bundles.
• Cohesin links centromere subdomains, preventing their separation and avoiding merotelic attachments.

Conclusions:

• The bipartite organization of vertebrate centromeres is a fundamental feature ensuring accurate chromosome segregation.
• Separation of these subdomains is linked to merotelic attachments observed in cancer cell divisions.
• This discovery provides insights into mechanisms maintaining genomic stability.