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Archive - May 5, 2009

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Primordial Gene Might Permit Bypass of Mitochondrial Defects

Researchers have shown that by providing Parkinson-disease-model fruit flies with a gene they don’t normally possess, they can rescue the flies from their Parkinson-like symptoms, including movement defects and excess free radicals produced in mitochondria. The key gene (single-subunit alternative oxidase or AOX) essentially acts as a bypass for blockages in the so-called oxidative phosphorylation (OXPHOS) cytochrome chain in mitochondria. Dr. Howard Jacobs, who led the study at the University of Tampere in Finland, likens that chain to a series of waterfalls in a hydroelectric power station. Only, in the case of mitochondria, it is electrons that flow to release energy that is captured in molecular form. Defects in mitochondrial OXPHOS are associated with diverse and mostly intractable human disorders, the researchers said. Therefore, there's a chance that the strategy might also prove beneficial in mammals, including humans, which, like insects, have also lost the AOX gene over the course of evolution. On the other hand, most plants, animals, and fungi do possess an alternative mitochondrial respiratory chain, which can bypass the OXPHOS system under specific physiological conditions. Their findings led the researchers to conclude that “AOX appears to offer promise as a wide-spectrum therapeutic tool in OXPHOS disorders.” “OXPHOS dysfunction is not just a problem in some rare genetic disorders or in degenerative diseases,” Dr. Jacobs added. It's an issue in a very large number of pathologies—and a major cause of tissue damage after heart attack and stroke.

Next-Gen Sequencing Speeds Mutation Mapping in Fruit Flies

A novel whole-genome sequencing approach using Illumina next-generation sequencing technology has been developed and used for mapping single-base mutations in the fruit fly. The novel methodology promises to reduce the time and effort required to identify mutations of biological interest. “This approach will change the way fruit fly genetics is done,” said Scott Hawley, Ph.D., a co-equal senior author on the publication. “Traditional mapping approaches to identify mutations are inefficient procedures. Our whole-genome sequencing approach is fast and cost-effective. Among other potential uses, it also carries the potential to pinpoint inheritable molecular characteristics that are controlled by several genes at once.” Model organisms like fruit flies are used in research for studying both normal biological processes and human disease. Fruit fly genes can be inserted, deleted, or modified, and large numbers of flies can be randomly mutated to generate interesting phenotypes relevant to human disease. Finding the mutated gene responsible for an interesting phenotype is currently labor-intensive and time-consuming, and many mutations that cause medically relevant phenotypes are not discovered. The new approach lowers the barrier to finding mutations and may greatly accelerate the discovery of genes important for human health, the researchers suggest. The study was published in the May issue of Genetics. [Stowers Institute release] [Genetics abstract]