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Posted by on Nov 5, 2012 in Science |

Identify the gene required for the regeneration of nerve cells

Identify the gene required for the regeneration of nerve cells

A team of researchers at Penn State University led by Professor Melissa Rolls has found the gene associated with the regeneration of damaged nerve cells . They found a mutation in a single gene that can turn the process by which the axons, the parts of the nerve cell that are responsible for sending signals to other cells grow back after a cut or injury.

Melissa Rolls explained it well after the publication of the study:

With this study we hope that the discovery opens the door to new research related to spinal cord and other neurological disorders in humans. The axons extend beyond those nerve cells, are able to survive all animal life. For this purpose, the nerve cells need to be flexible, and in the case of damage or wear, some damage can be repaired with the growth of new axons.

So far, studies have suggested that microtubules, the “highways” key intracellular in neurons that are in constant growth, they must be rebuilt as an important step in this type of repair. According Rolls:

In many ways, this idea makes sense to grow a new part of the nerve, microtubules need to be organized to make the new materials to the site of growth.

What the researchers did was to focus on the study of microtubule remodeling proteins in axonal regeneration after injury. They focused on a separate set of microtubule proteins into small pieces. On the whole, found a protein called spastin, a key protein in axon regeneration.

The fact that protein plays a critical role in the regeneration is particularly intriguing because in humans is encoded by a gene called SPG4 disease. When a copy of this gene is altered, affected individuals develop hereditary spastic paraplegia (HSP), which is characterized by progressive weakness and degeneration lower limbs of motor axons in the spinal cord. The identification of a new role for neuronal spastin can help us understand this disease.

To study the role played by the spastin, the team chose the fruit fly as a model organism. According Rolls:

At the molecular level, many of the processes associated with nerve cell growth and regeneration are the same in humans and fruit flies. Like all animals, including humans, fruit flies have two copies of each gene, one from each parent, so different combinations of each gene can lead to different observable traits.

The team went on to raise three genetically distinct groups of fruit flies in the lab to see how the different combinations of genes spastin might affect the behavior of nerve cells after injury. The first group of flies with two copies of the normal gene, the second had a normal copy and one mutant copy, and the third had two mutant copies. Finally, scientists cut into three groups axons of nerve cells and observed flies regeneration process.

What we saw was that in the group of flies with two normal copies of the gene, severed axons are re-assembled. Interestingly, in the other two groups, where the fruit flies had two or even one abnormal gene spastin simply no regrowth, indicating that what we have here is a pervasive problem.

In addition, the researchers found that the gene does not appear to play a role in the development stage when axons had met for the first time. The researchers found that, while the gene affected axons of flies, their dendrites, the parts of the neuron that receives information from other cells, continued to function normally and repaired.

Rolls finished the study explaining the meaning of progress from now:

Now we know that spastin plays an important role in axon regeneration and that this gene is dominant, we have opened a possible path to the study of human disease related to damaged nerve cells. In fact, our next step is to investigate the relationship between hereditary spastic paraplegia and axonal regeneration.

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