Related Experiment Video

Updated: May 16, 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

Anthrax toxin receptor 2a controls mitotic spindle positioning

I Castanon1, L Abrami, L Holtzer

  • 1Departments of Biochemistry and Molecular Biology, Sciences II, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.

Nature Cell Biology
|December 4, 2012
PubMed

Insights

Oriented cell division guides tissue development. This study reveals how anthrax toxin receptor 2a (Antxr2a) and actin filaments align cell division planes along the animal-vegetal axis during zebrafish gastrulation.

Area of Science:

  • Developmental Biology
  • Cell Biology
  • Molecular Biology

Background:

  • Oriented cell division is crucial for tissue morphogenesis.
  • The Wnt/planar cell polarity (Wnt/PCP) pathway is known to orient mitosis in various developmental systems.
  • The precise mechanism by which Wnt signaling controls mitotic orientation remains unclear.

Purpose of the Study:

  • To elucidate the molecular mechanism by which Wnt signaling orients the mitotic plane in dorsal epiblast cells during zebrafish gastrulation.
  • To identify key proteins involved in the Wnt-dependent orientation of cell division.

Main Methods:

  • Confocal microscopy to visualize protein localization and F-actin dynamics.
  • Biochemical assays to study protein-protein interactions.
  • Genetic manipulation to assess the function of key proteins in vivo.

Main Results:

  • Anthrax toxin receptor 2a (Antxr2a) accumulates in a polarized cortical cap aligned with the animal-vegetal (A-V) axis, predicting the division plane.
  • Filamentous actin (F-actin) also forms an A-V polarized cap, dependent on Wnt/PCP, RhoA, and Rock2.
  • Antxr2a interacts with actin and RhoA, activating zDia2 and exerting torque on the spindle to align it with the A-V axis.

Conclusions:

  • Antxr2a acts as a Wnt-dependent polarized determinant that orients cell division.
  • The Wnt/PCP pathway, through Antxr2a, RhoA, and zDia2, provides a mechanism for aligning mitotic spindles with the embryonic A-V axis.
  • This provides critical insights into the regulation of oriented cell division during tissue development.

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

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations07:14

Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations

Published on: September 20, 2019

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...
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...
The Spindle Assembly Checkpoint02:19

The Spindle Assembly Checkpoint

The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Anaphase A and B01:39

Anaphase A and B

Microtubules form through the end-to-end polymerization of tubulin heterodimers. Kinetochore microtubules originate from the spindle poles, and their plus-ends connect with the kinetochores on sister-chromatids. Ndc80 protein complexes, present on the kinetochore, form low-affinity links with the plus end of these kinetochore microtubules.
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
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...