The development of the brain in the embryo is a highly complex process. In its course, countless cells migrate from their place of origin to the place where they will later be needed. How exactly this works has only been understood in rudimentary form. Scientists at the University of Bonn have now identified a possible mechanism. According to this, a bundle of nerve fibers could function as a kind of “railway” along which the cells reach their target. The study which is already available online, will soon appear in the journal “Development”.
In their study, the researchers examined the brain development of mouse embryos. They concentrated on a pool of neuronal precursor cells that develops in the hindbrain about ten days after fertilization.
These mature into nerve cells and then migrate to other regions in the developing hindbrain. Similar complex cell migrations also occur in humans during early brain development.
“However, there is still little understanding of how the whole process works,” explains Prof. Dr. Sandra Blaess from the Institute of Reconstructive Neurobiology at the University of Bonn.
It is known that a protein called GLI3 plays a role in the organization of the nascent brain. But what exactly is its function in hindbrain development? This question was investigated by Erick Martinez-Chavez, PhD student of Prof. Blaess, together with his colleague Claudia Scheerer and Dr. Andrea Wizenmann from the University of Tübingen.
For this purpose, the scientists first switched off GLI3 production in mice completely. As a result, the migration of these nerve cells was severely disturbed in the embryos.
The researchers then repeated their experiment, but only stopped GLI3 production in the developing nerve cells. These were surprisingly unperturbed by this: They started their journey to their target regions as normal. GLI3 is therefore not directly needed to get them going. “Its function must be somewhere else,” emphasizes Martinez-Chavez. But where?
Does a nerve path function as a “railroad”?
Outside of the brain and spinal cord (the central nervous system), there are countless other nerve pathways and nerve cells in animals, which in their entirety are referred to as the peripheral nervous system. They are for instance responsible for transmitting electrical impulses to the muscles.
Although peripheral nerve cells are located outside the brain, they form projections that extend into the brain. They do not do this individually, but in the form of bundles - similar to a cable harness in a computer. Brain researchers then speak of nerve tracts.
The Bonn scientists have now been able to show that some of the neurons seem to orient themselves along one of these tracts when migrating to their target region: The cells move along the tract almost like on a rail. But this only worked in mouse embryos that produced GLI3.
In embryos lacking GLI3, the bundling of nerve processes was much looser than normal: The paths frayed, so to speak a feature that was clearly visible under the microscope.
“We assume that the fraying of the nerve tracts leads to the loss of their rail function,” says Prof. Blaess. The function of GLI3 in the formation of the tract and the mechanisms regulating the interaction between nerve cells and the tract still need to be clarified in further studies.
In the long run, the results could help to improve the understanding of certain developmental disorders of the brain. Above all, however, they provide a fascinating insight into the organization of our brain, and into the complex processes that have to be tightly coordinated for correct brain development.
Prof. Dr. Sandra Blaess
Heisenberg Professorship for Developmental Neurobiology
Institute for Reconstructive Neurobiology
University of Bonn
Erick Martinez-Chavez, Claudia Scheerer, Andrea Wizenmann and Sandra Blaess: The zinc-finger transcription factor GLI3 is a regulator of precerebellar neuronal migration; Development; dx.doi.org/10.1242/dev.166033
Dr. Andreas Archut | idw - Informationsdienst Wissenschaft
How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin
Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
18.01.2019 | Materials Sciences
18.01.2019 | Life Sciences
18.01.2019 | Health and Medicine