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Three scientists who helped figure out why all life doesn’t simply collapse in a pile of broken DNA won the Nobel Prize in Chemistry Wednesday. Their findings underlie research into treatments for cancer and aging.
The three -- Tomas Lindahl of the Francis Crick Institute and Clare Hall Laboratory in Britain, Paul Modrich, a Howard Hughes Medical Institute researcher at Duke University School of Medicine and Aziz Sancar of the University of North Carolina – each found a different way that cells use to fix broken DNA.
“The reason our genetic material does not disintegrate into complete chemical chaos is that a host of molecular systems continuously monitor and repair DNA,” the Nobel Committee said in a statement.
The Swedish-born Lindahl discovered frightening evidence that DNA breaks down so quickly that life should not be possible. “His insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA,” the committee said.
“The reason our genetic material does not disintegrate into complete chemical chaos is that a host of molecular systems continuously monitor and repair DNA."
This system fixes the damage done by radiation, alcohol, smoking and other threats.
“DNA repair enzymes are analogous to proofreaders of a text, continually searching for errors in the DNA alphabet of four letters (A, T, G and C), and probably succeeding in 99 percent of cases,” Malcolm Alison, a professor of stem cell biology at Queen Mary University of London, said in a statement.
New Mexico-born Paul Modrich figured out a process called mismatch repair that cells use to fix mistakes made when they divide.
“Defects in DNA mismatch repair increase the risk of developing hereditary colon cancer, for instance. In fact, in many forms of cancer, one or more of these repair systems have been entirely or partially switched off,” the Nobel committee said. “This makes the cancer cells’ DNA unstable, which is one reason why cancer cells often mutate and become resistant to chemotherapy.”
It’s a process that constantly prevents cancer. “Today we know that all but one out of a thousand errors that occur when the human genome is copied, are corrected by mismatch repair,” the committee said.
The Turkish-born Aziz Sancar found a mechanism called nucleotide excision repair that the body uses to repair ultraviolet light’s damage to DNA.
'Today we know that all but one out of a thousand errors that occur when the human genome is copied, are corrected by mismatch repair."
“His interest was piqued by one phenomenon in particular: when bacteria are exposed to deadly doses of UV radiation, they can suddenly recover if they are illuminated with visible blue light. Sancar was curious about this almost magical effect; how did it function chemically?” the Nobel committee said.
His work didn’t impress employers but Sancar persisted, the committee noted.
The Nobel prize in medicine went to pioneers in drugs drawn from nature on Monday and the prize in physics went for research into subatomic particles called neutrinos on Tuesday. The Nobel announcements continue with literature on Thursday, the Nobel Peace Prize on Friday and the economics award on Monday.