Partnership of genes affects the brain's development (w/ Video)

Feb 13, 2011
The photoreceptor nerve cells (green) of the fly's compound eye send their axons to the brain's optic ganglia. Scientists have now discovered that the axons are able to recognize their target area in the brain thanks to the interaction of two genes. Credit: Max Planck Institute of Neurobiology / Suzuki

The human brain consists of approximately one hundred billion nerve cells. Each of these cells needs to connect to specific other cells during the brain's development in order to form a fully functional organism. Yet how does a nerve cell know where it should grow and which cells to contact? Scientists of the Max Planck Institute of Neurobiology in Martinsried have now shown that growing nerve cells realise when they've reached their target area in the fly brain thanks to the interaction of two genes. Similar mechanisms are also likely to play a role during the development of the vertebrate brain and could thus be important for a better understanding of certain developmental disorders.

The is incredibly complex. Millions and even many billion are created during development. Each of these cells sets up connections to their neighbouring cells and then sends out a long connecting cable, the axon, to a different brain region. Once the axon has reached its target area it connects itself with the local nerve cells. In this way a processing chain is established which allows us, for example, to see a cup, recognize it as such, reach out and take hold of it. Had there been a misconnection between the nerve cells somewhere along the way between the eyes and the hand, it would be impossible to reach the coffee in the cup.

This video is not supported by your browser at this time.
This is a 3D-rotation through the optic lobe of a fly larva's brain. Blue are axons of the photoreceptor nerve cells, the two guidance proteins are shown in green (GoGo) and magenta (Flamingo). Credit: Max Planck Institute of Neurobiology / Suzuki

It is thus essential for nerve cells to connect to the correct partner cells. Based on this fact, scientists of the Max Planck Institute of in Martinsried and colleagues from Kyoto investigated how an axon knows where it should stop growing and start setting up connections with surrounding cells. For their investigation, the neurobiologists analyzed the function of that play a role in the development of the visual system of the fruit fly.

The scientists now report in the scientific journal that the visual system of the fruit fly is only able to develop correctly, when two genes work together – the genes, that are in charge of producing the proteins "Golden Goal" and "Flamingo". These two proteins are located at the tip of a growing axon, where they are believed to gather information about their environment from the surrounding tissue. The actions of these two proteins enable nerve cells in a number of ways to find their way in the brain and recognize their target area. The study showed that chaos results if only one of the genes is active, or if there is a mismatch in the genes' activity: the axons cease to grow somewhere along the way and never reach their target area.

"We assume that very similar mechanisms play a role also in other organisms – including humans", explains Takashi Suzuki, lead author of the study. "We are now a good way into understanding how to manipulate the cells in such a way that they are certain to reach their target area." This knowledge would be an important foundation for eventual therapies of developmental disorders based upon a misguided growth of nerve cells. The knowledge may also help in the guidance of regenerating nerve cells back to their old connection sites.

Explore further: Lou Gehrig's disease study: Renewing brain's aging support cells may help neurons survive

More information: Hakeda-Suzuki S et al., Golden Goal Collaborates with Flamingo in Conferring Synaptic-Layer Specificity in the Visual System, Nature Neuroscience, February 14 2011

Related Stories

Milestone in the regeneration of brain cells

Aug 20, 2007

The majority of cells in the human brain are not nerve cells but star-shaped glia cells, the so called “astroglia”. “Glia means “glue”, explains Götz. “As befits their name, until now these cells have been regarded ...

The dormant potential of damaged nerve cells

Jul 13, 2009

(PhysOrg.com) -- Damaged nerve cells in a finger will regrow, but those in the spinal cord do not. Why the difference? Scientists at the Max Planck Institute for Neurobiology working with an international ...

Stem cells use GPS to generate proper nerve cells

May 11, 2010

An unknown function that regulates how stem cells produce different types of cells in different parts of the nervous system has been discovered by Stefan Thor, professor of Developmental Biology, and graduate students Daniel ...

The building blocks of memory

Aug 20, 2007

Learning new things, remembering past experiences and adapting to a changing environment - these abilities carried out by the brain are essential for day-to-day survival. This unique flexibility is in part ...

Recommended for you

Fruit fly lights up brain wiring

3 hours ago

(Medical Xpress)—Fluorescent fruit flies have helped University of Queensland researchers take a critical step toward understanding the human brain's neuronal "wiring" and how it can go awry.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.