Insights from the fruit fly on human susceptibility to arsenic poisoning.
Ortiz, JGM, R Opoka, D Kane and IL Cartwright. 2008. Investigating arsenic susceptibility from a genetic perspective in Drosophila reveals a key role for glutathione synthetase. Toxicological Sciences online September 8, 2008.
New data from a study on fruit flies provides clues as to why some humans are more susceptible to arsenic poisoning than others. The researchers found that some flies have genes that can change the element arsenic from harmful to safe. Human exposure to arsenic via drinking water remains a critical health issue for many countries, such as Bangladesh and some industrialized nations like China and the U.S. Chronic exposure to arsenic can cause disease, including several types of cancer, diabetes, vascular disease and skin lesions. There is evidence that some people may be more or less sensitive to arsenic poisoning compared to the population at large. This may be due to differences in the genetic code among people; slight differences in DNA sequences can lead to significance changes in the way our bodies fight off disease or handle toxic exposures. In this study, Dr. Ortiz and his colleagues used fruit flies to understand how gene variation might impact human susceptibility to arsenic poisoning. They identified a small region on the X chromosome that was required for the fruit flies to mount a defense against arsenic toxicity. This region turned out to be the location for a gene called glutathione synthetase (GS), which codes for a key enzyme that aids in detoxifying arsenic. GS functions much the same way in fruit flies as in humans. These data provide “genetic proof” that the GS metabolism pathway is crucial for a “robust defense” against arsenic toxicity. Moreover, individuals with a form of GS that is not fully functional may be at greater risk of arsenic poisoning.