Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Figuring out the ups and downs—and sideways—of neural development

23.11.2005


One of the key controllers of neural development seems to depend on a simple cellular decision--whether to divide perpendicularly or in parallel to the embryonic structure called the neuroepithelium. Nevertheless, such orientation is critical, and understanding its machinery could help neuroscientists learn to control the division of adult neural stem cells to regenerate neural tissues.



Researchers know that during the earliest embryonic brain development, neural stem cells divide "symmetrically," producing identical immature progenitor cells that continue to proliferate. A bit later, however, when neural tissues need to begin to differentiate, the cells divide "asymmetrically," producing one proliferating progenitor and another that stops proliferating and differentiates into an adult neural cell. And during final brain development, the cells return to symmetric cell division, creating differentiated adult cells.

The two types of cell division seem to be governed by the orientation of the tiny bundles of fiber-like microtubules called spindles inside the dividing cell--whether the spindles are oriented parallel or perpendicular to the neuroepithelium. These spindles attach to the dividing chromosomes in the nucleus and drag the two copies apart, ensuring that each daughter cell has its fair share.


In an article in the November 23, 2005, issue of Neuron, Mihaela Žigman and colleagues have pinpointed a key regulator of spindle orientation in mammals. They drew on discoveries made in the fruit fly Drosophila, in which other researchers had found a gene called Inscuteable to be a central controller of spindle orientation. Analyzing genetic databases, Žigman and colleagues determined that versions of the Inscuteable gene could be found in higher animals, including mice, rats, and humans. Also, they found in their experiments, the mammalian version of Inscuteable (mInsc) appeared in regions of the cell and activated itself at times during cell division that was consistent with a role in spindle orientation.

Studying developing retinal tissue of embryonic rats, they observed that the protein produced by the mInsc gene concentrated at places in the developing cell that suggested a role in controlling spindle orientation.

And in key experiments, when they knocked-out activity of mInsc in the rat retina, they found abnormal spindle orientation. And importantly, in the rats lacking mInsc activity, they also observed abnormal retinal development, apparently because of a continued division that favors proliferating progenitor cells. In that tissue, the number of normal photoreceptor cells was reduced and the number of another type of neuron increased.

"We show that mInsc depletion ablates vertical mitotic spindle orientation in retinal progenitors and leads to defects in cell-fate specification and proliferation," concluded Žigman and colleagues. "Our results demonstrate that spindle orientation not only predicts but actually determines the fate of the two daughter cells.

"This identification of mInsc provides a unique tool to analyze the importance of oriented divisions in various other vertebrate tissues," they wrote. "For example, it was proposed that adult mammalian neural stem cells divide asymmetrically along the apical basal axis. It will be interesting to test whether spindle orientation is essential for asymmetric stem cell divisions as well. If so, this will be an important factor in exploring the regenerative capacity of these cells."

Heidi Hardman | EurekAlert!
Further information:
http://www.neuron.org
http://www.cell.com

More articles from Life Sciences:

nachricht Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)

nachricht CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>