Unformatted text preview: TRANSGENES I N MA M MALS KLUG pg. 543-544 & reading provided 21.5 Geneticists Advance Ou r Understanding of Molecular P rocesses by Undertaking Genetic Research in Model Organisms: Th ree Case Studies The Mouse: A Model for ALS Gene Therapy -amyotrophic lateral sclerosis (ALS): incurable neurodegenerative disease that leads to progressive destruction of motor neurons in the brain and spinal cord brain no longer controls movement and the muscles weaken and atrophy difficulties w/speech, breathing, swallowing, eventually leading to full paralysis but does not affect intellectual ability, hearing, sight, other senses -20% of familial cases of ALS are associated with dominant mutations in the Cu/Zn superoxide dismutase gene, SOD1. The SOD1 gene encodes an antioxidant enzyme (SOD) that converts superoxide radicals to hydrogen peroxide and molecular oxygen SOD protects cells from damage caused by these by-products of aerobic metabolism -geneticists created t ransgenic mice bearing a human SOD1 gene by cloning the 14.5 kilobase pair human genomic DNA fragment containing the G93A gene along w/the gene's promoter region and they injected this DNA into mouse eggs and retuned the eggs to a surrogate mother // a number of t ransgenic SOD mice were generated and these t ransmit ted the t ransgene to 50% of their progeny -conclusions from mice experiment: G93A mutation doesn't affect the activity of the SOD enzyme. M ice carrying homozygous null mutations in the SOD1 gene are normal. Therefore, loss of SOD enzyme activity is unlikely to be cause of ALS. The disease is not likely to be caused by overexpression of SOD1. However, SOD1 mutations in ALS may cause the SOD protein to become toxic. ...
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This note was uploaded on 09/02/2009 for the course BIO 315H taught by Professor Payne during the Spring '08 term at University of Texas.
- Spring '08