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Glutamine Glut and Disease
Zoghbi To Deliver NIH Director's Lecture, Feb. 12 in Masur

By Jennifer Wenger

Spinocerebellar ataxia type 1, a hereditary disorder of the nervous system that makes it increasingly difficult for a person to move and speak, is marked by an errant protein that results when three nucleotides collectively coding for the amino acid glutamine — C, A and G — are repeated many times over. Similar neurological disorders such as Huntington's disease, spinobulbar muscular atrophy and other types of spinocerebellar ataxia are caused by repetition of the same three nucleotides in different genes.

In the upcoming NIH Director's Lecture, "Pathogenesis Studies of Polyglutamine-induced Neurodegenerative Diseases," Dr. Huda Y. Zoghbi, professor of neuroscience and genetics at Baylor College of Medicine, Houston, and investigator for the Howard Hughes Medical Institute, will discuss her recent research findings on spinocerebellar ataxia and similar neurological disorders caused by the recurring amino acid. The lecture will take place on Wednesday, Feb. 12, at 3 p.m. in Masur Auditorium, Bldg. 10.

Dr. Huda Y. Zoghbi A co-discoverer of the gene that causes spinocerebellar ataxia type 1, SCA1, Zoghbi has studied the effects of the mutant form of the ataxin-1 protein — what SCA1 encodes — in both mice and fruit flies. For example, she and collaborators have found that the expanded ataxin-1 is resistant to the normal cellular process by which healthy proteins are broken down and recycled, thus making the disease more likely to occur. How different types of cells in the brain cope with the mutant protein is another subject of interest. Cells that are able to capture the misshapen proteins early on and stash them away in the nucleus are likely to suffer less damage than those in which the protein roams free, she and her colleagues have demonstrated.

In a June 2002 article in the journal Neuron, Zoghbi and colleagues describe how, by inserting 154 repeats of the CAG trinucleotide into the mouse's Sca1 gene locus, researchers can produce a mouse that exhibits characteristics strikingly similar to the human form of the disease. Previously, the mouse's comparatively short lifespan, and hence, its inability to exhibit some of the symptoms that occur in humans in the later stages of the disease, limited researchers' ability to use the mouse as a model for understanding how the disease affects people.

What makes the repeating amino acid so toxic to a neuron, and why some regions of the brain are affected more drastically than others are two topics that Zoghbi will be addressing. She will also discuss how the study of mouse and fruit fly models will help shine new light on the cause — and possible treatment — of spinocerebellar ataxia and related neurodegenerative disorders.

Born in Beirut, Lebanon, Zoghbi earned a B.S. degree in biology from the American University of Beirut in 1975, where she also began medical school. When civil war broke out in Lebanon, she transferred to Meharry Medical College, Nashville, earning her M.D. degree in 1979. She has been a member of the Baylor faculty since 1988, and is also a pediatrician at Houston's Texas Children's Hospital and Ben Taub General Hospital. She was named investigator for the Howard Hughes Medical Institute in 1996.

Zoghbi's honors include the Sidney Carter Award from the American Academy of Neurology, the Javits Neuroscience Investigator Award from NINDS and the E. Mead Johnson Award for Research in Pediatrics from the Society for Pediatric Research. She was elected to the National Academies' Institute of Medicine in 2000 and the American Association for the Advancement of Science in 2002.

In addition to locating the gene for spinocerebellar ataxia type 1, Zoghbi discovered the gene that causes Rett syndrome and identified Math1, a gene that governs the development of hair cells in the inner ear.

The talk is part of the NIH Director's Wednesday Afternoon Lecture series. For more information or for reasonable accommodation, call Hilda Madine, 594-5595.