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DNA Damage & Repair

Professor Zvi Livneh
Maxwell Ellis chair of Biomedical Research at the Weizmann Institute of Science

One research effort sponsored by the Weizmann Institute focuses on the continuing war waged against humanity by the smallest creatures on the planet - bacteria and viruses - and their increasing ability to resist antibiotics. Prof. Zvi Livneh described how information gained from studies of common E. coli has helped to isolate a crucial enzyme that seems to regulate the process of DNA repair and genetic mutation. The enzyme, called DNA polymerase V, discovered at the Weizmann Institute, seems to function specifically to allow DNA to replicate despite "errors" in the genetic code. He believes that these enzymes may be the reason why bacteria are so adept at developing resistance to antibiotics.

"It's a cops and robbers story," Prof. Livneh said. Drugs are employed to fight certain types of bacteria, but because bacteria replicate so rapidly, they can develop mutations that allow them to resist the drugs' effects. Newer drugs then need to be discovered and deployed, starting the cycle again. It has worked this way since antibiotics were first used, but with the discovery of polymerase V, Prof. Livneh explained, it may be possible to invent a drug that suppresses the enzyme, thereby prolonging antibiotic effectiveness. Prof. Livneh is also studying how DNA repair can influence a person's susceptibility to cancer. Though heredity and environmental factors play significant roles in some types of cancers, another major factor is the body's own ability - or inability - to repair DNA damage.

Prof. Livneh has developed a simple blood test to identify an individual's ability to repair DNA damage - a repair efficiency index. A person with a high DNA-repair efficiency can more readily avoid the mutations that can cause cells to become cancerous. Ongoing clinical trials have shown that some people possess exceptionally high repair efficiency, while others have a significantly lower ability. The latter group seems to be at greatest risk for cancer.

Prof. Livneh believes that such knowledge is extremely useful. "If we can measure a person's tendencies," he said, "we can help that person engage in preventive behavior, thereby decreasing their cancer risks."

Source: Weizmann Now, 130 E. 59th St., NY, NY 10022

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