Related Experiment Video

Updated: Jul 24, 2026

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
10:52

Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets

Published on: August 13, 2016

Chromosome movement in mitosis requires microtubule anchorage at spindle poles

M B Gordon1, L Howard, D A Compton

  • 1Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.

The Journal of Cell Biology
|February 7, 2001
PubMed

Insights

Microtubule anchorage at spindle poles by NuMA and HSET is crucial for chromosome movement during cell division. Disrupting these proteins prevents chromosomes from moving poleward, halting mitosis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • Spindle pole organization is vital for chromosome segregation during mitosis.
  • Microtubule minus-end anchorage at spindle poles is hypothesized to manage forces for chromosome movement.
  • Nuclear mitotic apparatus protein (NuMA) and HSET are key noncentrosomal proteins in spindle pole organization.

Purpose of the Study:

  • To investigate the role of NuMA and HSET in microtubule anchorage and chromosome movement during mitosis.
  • To test the hypothesis that spindle pole anchorage bears the load of poleward forces.

Main Methods:

  • Perturbation of NuMA and HSET in animal cells.
  • Monitoring chromosome movement during mitosis using live-cell imaging.
  • Immunofluorescence and electron microscopy to analyze microtubule attachment and spindle organization.

Main Results:

  • NuMA or HSET perturbation alone caused minor defects in spindle organization and cell cycle progression.
  • Simultaneous perturbation of NuMA and HSET severely impaired directed chromosome movement.
  • Chromosomes failed to segregate, coalescing centrally on bi-oriented spindles lacking organized poles.
  • Microtubule attachment to kinetochores occurred, but failed to generate tension.

Conclusions:

  • Spindle pole anchorage, mediated by both NuMA and HSET, is essential for proper chromosome movement.
  • These proteins play overlapping roles in ensuring microtubule minus-end anchorage for mitotic forces.
  • Dysfunctional anchorage leads to failed chromosome segregation and mitotic arrest.

More Related Videos

Directly Measuring Forces Within Reconstituted Active Microtubule Bundles07:47

Directly Measuring Forces Within Reconstituted Active Microtubule Bundles

Published on: May 10, 2022

Self-Assembly of Microtubule Tactoids08:49

Self-Assembly of Microtubule Tactoids

Published on: June 23, 2022

Related Concept Videos

The Mitotic Spindle02:27

The Mitotic Spindle

The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures bipolar mitotic...
Spindle Assembly02:50

Spindle Assembly

Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a microtubule array...
Attachment of Sister Chromatids02:57

Attachment of Sister Chromatids

As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules.  Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall of a...
Forces Acting on Chromosomes02:11

Forces Acting on Chromosomes

During mitosis, chromosome movements occur through the interplay of multiple piconewton level forces. In prometaphase, these forces help in chromosome assembly or congression at the equatorial plane, eventually leading to their alignment at the metaphase plate. The forces acting on the chromosomes are space and time-dependent; therefore, they vary with the position of the chromosomes as the cell progresses through mitosis. 
Microtubules and motor proteins exert two types of forces on...
The Mitotic Spindle02:27

The Mitotic Spindle

The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures bipolar mitotic...
Attachment of Sister Chromatids02:57

Attachment of Sister Chromatids

As cells progress into mitosis, the nuclear envelope breaks down, and the condensed chromosomes are exposed to the array of bipolar microtubules of the mitotic spindle. The kinetochore, a large, disc-shaped protein complex, is present at the centromere region of the sister chromatids and acts as a binding site for the microtubules.  Usually, the plus-end of a single microtubule is embedded within the kinetochore. However, some kinetochores first establish lateral contact with the side-wall of a...