Format

Send to

Choose Destination
Chromosome Res. 2018 Dec;26(4):277-295. doi: 10.1007/s10577-018-9584-1. Epub 2018 Aug 24.

Condensin controls mitotic chromosome stiffness and stability without forming a structurally contiguous scaffold.

Author information

1
Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA.
2
Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA.
3
Department of Molecular Biosciences, Northwestern University, Evanston, IL, 60208, USA. john-marko@northwestern.edu.
4
Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208, USA. john-marko@northwestern.edu.
5
Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, IL, 60208-3500, USA. john-marko@northwestern.edu.

Abstract

During cell division, chromosomes must be folded into their compact mitotic form to ensure their segregation. This process is thought to be largely controlled by the action of condensin SMC protein complexes on chromatin fibers. However, how condensins organize metaphase chromosomes is not understood. We have combined micromanipulation of single human mitotic chromosomes, sub-nanonewton force measurement, siRNA interference of condensin subunit expression, and fluorescence microscopy, to analyze the role of condensin in large-scale chromosome organization. Condensin depletion leads to a dramatic (~ 10-fold) reduction in chromosome elastic stiffness relative to the native, non-depleted case. We also find that prolonged metaphase stalling of cells leads to overloading of chromosomes with condensin, with abnormally high chromosome stiffness. These results demonstrate that condensin is a main element controlling the stiffness of mitotic chromosomes. Isolated, slightly stretched chromosomes display a discontinuous condensing staining pattern, suggesting that condensins organize mitotic chromosomes by forming isolated compaction centers that do not form a continuous scaffold.

KEYWORDS:

cell division; chromosome compaction; chromosome mechanics; chromosome stretching; colchicine; condensin; mechanobiology; metaphase chromosome; mitosis; non-histone proteins; structural maintenance of chromosome protein

PMID:
30143891
PMCID:
PMC6370136
DOI:
10.1007/s10577-018-9584-1
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Springer Icon for PubMed Central
Loading ...
Support Center