From M.I.T. : “Possible role for Huntington’s gene discovered”

January 16, 2013
Anne Trafton, MIT News Office

Mutant forms of the gene disrupt chemical modifications that control access to genes necessary for normal brain cell function.

About 20 years ago, scientists discovered the gene that causes Huntington’s disease, a fatal neurodegenerative disorder that affects about 30,000 Americans. The mutant form of the gene has many extra DNA repeats in the middle of the gene, but scientists have yet to determine how that extra length produces Huntington’s symptoms.

brain
The gene that causes Huntington’s disease does most of its damage in the basal ganglia, shown in pink. The basal ganglia are responsible for many functions, including voluntary motor control and habit formation. Image: U.S. Food and Drug Administration

In a new step toward answering that question, MIT biological engineers have found that the protein encoded by this mutant gene alters patterns of chemical modifications of DNA. This type of modification, known as methylation, controls whether genes are turned on or off at any given time.

The mutant form of this protein, dubbed huntingtin, appears to specifically target genes involved in brain cell function. Disruptions in the expression of these genes could account for the neurodegenerative symptoms seen in Huntington’s disease, including early changes in cognition, says Ernest Fraenkel, an associate professor of biological engineering at MIT.

Fraenkel’s lab is now investigating the details of how methylation might drive those symptoms, with an eye toward developing potential new treatments. ‘One could imagine that if we can figure out, in more mechanistic detail, what’s causing these changes in methylation, we might be able to block this process and restore normal levels of transcription early on in the patients,’ says Fraenkel, senior author of a paper describing the findings in this week’s issue of the Proceedings of the National Academy of Sciences.”

See the full article here.


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