Physics of Living Systems

Cell-cycle and Age-Related Modulations in Mouse Chromosome Stiffness

Ning Liu
Wenan Qiang
Philip Jordan
John Marko author has email address
Huanyu Qiao author has email address

Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
Center for Developmental Therapeutics, Northwestern University, Evanston, IL, USA
Biochemistry and Molecular Biology Departments, Johns Hopkins University, Baltimore, MD, USA
School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA

https://doi.org/10.7554/eLife.97403.1

Open access
Copyright information

Figures and data

Chromosome isolation from oocytes.
(A) Oocytes after zona pellucida removal. Left panel: MI oocyte. Right panel: MII oocyte with polar body. Scale bar = 10 μm. (B) Spindle isolation process. Left panel: Spindle flowing out of the oocyte after oocyte lysis. Middle panel: isolate a chromosome from a spindle-chromosome complex. Right panel: chromosome captured by two pipettes. Scale bar = 10 μm.

Chromosome stiffness measurement.
(A) Example images of chromosome isolation. Left: a MII oocyte chromosome. Right: a MI oocyte chromosome. Scale bar = 10 μm. (B) Chromosome stiffness comparison between mitotic cells (n=8), MI oocytes(n=8), MII oocytes (n=8) and WT spermatocytes at prophase I stage (n=8).

Chromosome stiffness measurement from meiosis-specific cohesin mutant.
(A) Chromosomes isolation images of Stag3^-/- spermatocytes. Scale bar = 10 μm. (B) Chromosome stiffness comparison between WT spermatocytes at prophase I stage (n=8), Rec8^-/- spermatocytes at prophase I stage (n=8), Stag3^-/- spermatocytes at prophase I stage (n=9) and Rad21l^-/- spermatocytes (n=10).

Aged chromosomes have higher chromosome stiffness.
(A) Chromosomes isolation images of an old MI oocyte. Left: old MI oocyte images. Middle: a spindle isolated from the old MI oocyte. Right: a chromosome isolated from the spindle-chromosome complex. Scale bar = 10 μm. (B) Chromosome stiffness comparison between the 3-4 weeks old MI oocytes (n=8) and 48 weeks old MI oocytes (n=5).

Etoposide treatment reduces chromosome stiffness.
(A) Chromosomes isolation images of a MI oocyte treated with 50μg/ml etoposide. Left: a spindle after cell lysis. Middle: a spindle captured with pipettes. Right: chromosome isolation. Scale bar = 10 μm. (B)Staining of control and 50μg/ml etoposide-treated MI oocytes. Scale bar = 10 μm. (C) Chromosome stiffness comparison between mitotic cells (n=8), MI oocyte control (n=8) and 50μg/ml etoposide-treated MI oocyte (n=8).

Chromosomes stiffness of different types of cells.
Chromosome doubling force comparison between mitotic cells (n=8), MI oocytes (n=8), MII oocytes (n=8) and WT spermatocytes at prophase I stage (n=8).

Chromosomes isolation images of Rec8^-/- spermatocytes.
Chromosomes were isolated from Rec8^-/- spermatocytes and captured with two pipettes. Scale bars = 10 μm.

Chromosomes isolation images of Rad21l^-/- spermatocytes.
Chromosomes were isolated from Rad21l^-/-spermatocytes and captured with two pipettes. Scale bars = 10 μm.

Sign up for email alerts