Jumpstarting DNA Repair. (Genetic Research)
Spivey, Angela, Environmental Health Perspectives
Every day, your DNA suffers damage--ultraviolet radiation, pollution, and cigarette smoke all take their toll. If unchecked, this damage can produce more extensive DNA lesions that result in tumors. Fortunately, DNA continuously repairs this damage. Now, for the first time, scientists have identified a protein that senses DNA damage from ultraviolet radiation and may trigger the repair process, known as the DNA damage checkpoint system.
A team from the University of North Carolina at Chapel Hill have found that a protein named ATR directly binds to DNA. Their study, published in the 14 May 2002 issue of Proceedings of the National Academy of Sciences, adds to scientists' broad knowledge about cancer and how cells protect themselves from DNA damage. "The DNA damage checkpoint system is really what determines cell death or survival, in both normal cells and cancerous cells," says principal investigator Aziz Sancar, a professor of biophysics and biochemistry. "ATR is a key protein in understanding this system."
Scientists already knew that ATR was somehow involved in the damage checkpoint system, but some had speculated that an intermediary protein actually sensed the damage. "We demonstrated that, without an intermediary, ATR binds to DNA, and when there is DNA damage [ATR] binds with higher affinity," says Sancar. "It is the first biochemistry paper showing that this protein has affinity for damaged DNA and can sense the damage directly. …