Armed with a grant from the U.S. Department of Energy, the scientists are using the rapidly developing zebrafish embryo to study the effects of low doses of radiation - the type of radiation many of us encounter daily - during the earliest and most delicate stage of life.

Ionizing radiation - which has shorter, more powerful wavelengths than visible or ultraviolet light - undoubtedly is strong enough to break apart chemical bonds in the body, including DNA, says Dr. William S. Dynan, biochemist and chief of the Program in Gene Regulation at the Medical College of Georgia Institute of Molecular Medicine and Genetics.

Dr. Dynan, principal investigator on the new $750,000, three-year grant, has been studying how cells respond to radiation that can break one or both strands of the double-stranded DNA, leading to cell death, successful cell repair or misrepair that may result in cancer.

But key issues still unexplored are whether the low levels of radiation all around us - even inside us in unstable forms of common elements such as potassium and hydrogen - cause problems and exactly what genes and proteins in the body help repair and, more importantly, prevent damage.

"The reason to do this in fish is to look at mechanisms of injury and innate mechanisms for repair and protection," Dr. Dynan says. "We want to know what goes wrong first. What is the most sensitive tissue? Is there a threshold for damage? We don't know the answer to either question. We might come up with some reassuring answers here. We could find there is a threshold. We could find that the damage is completely self-healing below a certain amount."

The researchers are exposing zebrafish embryos - which grow outside the mother and have developed, functioning organs within three days - to levels of radiation that mimic what humans routi
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Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
4-Nov-2003