Related Experiment Video
Updated: Jun 13, 2026
10:52
Reconstitution of Basic Mitotic Spindles in Spherical Emulsion Droplets
Published on: August 13, 2016
Cortical actin dynamics facilitate early-stage centrosome separation.
Jian Cao1, Justin Crest, Barbara Fasulo
1Sinsheimer Laboratories, Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
Current Biology : CB
|April 23, 2010
Summary
Dynamic actin rearrangements drive centrosome separation before nuclear envelope breakdown in Drosophila embryos. This process requires Arp2/3 and Formin, but not myosin II, impacting cell migration and division.
Area of Science:
- Cell Biology
- Developmental Biology
- Cytoskeleton Dynamics
Background:
- Centrosome separation is crucial for bipolar spindle formation.
- The role of actin in centrosome separation is debated, with some studies suggesting active motor involvement and others a passive role.
Purpose of the Study:
- To investigate the role of the actin cytoskeleton in centrosome separation prior to nuclear envelope breakdown (NEB) in Drosophila embryos.
- To elucidate the specific actin remodeling mechanisms and associated proteins involved in early centrosome separation.
Main Methods:
- Utilized Drosophila embryos for in vivo studies.
- Investigated the requirement for myosin II, Arp2/3, Formin, and the Apc2-Armadillo complex in centrosome separation.
- Observed actin dynamics and centrosome positioning relative to NEB.
Main Results:
- Actin rearrangements at the interphase cap edge, not myosin II, are essential for centrosome separation before NEB.
- Both Arp2/3 and Formin-mediated actin remodeling are required for this pre-NEB separation.
- The Apc2-Armadillo complex links actin cap expansion to centrosome separation.
- Post-NEB separation mechanisms are actin-independent.
Conclusions:
- Actin polymerization dynamics are the primary drivers of centrosome separation before NEB.
- These findings have implications for understanding centrosome positioning in cell migration, polarity, and asymmetric division.
Related Concept Videos
02:50Spindle 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...
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...
01:13Centrioles and Centrosomes
Most animal cells comprise a pair of centrioles together called a centrosome. The cell duplicates its centrosome and contains two centrosomes side-by-side, which begin to move apart during the prophase. As the centrosomes migrate to two different sides of the cell, microtubules start extending from each centrosome toward the other end. The mitotic spindle is composed of the centrosomes and their emerging microtubules.
Near the end of the prophase, also called late prophase or "prometaphase,"...
Near the end of the prophase, also called late prophase or "prometaphase,"...
02:25Centrosome Duplication
The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
02:25Centrosome Duplication
The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...
02:17Separation of Sister Chromatids
At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
At the onset of anaphase, separase, a proteolytic enzyme, is...