IMAGE: Ultraviolet radiation, such as sunlight, can damage cellular DNA, leading to cancer. UC San Diego researchers have described the underlying mechanism that helps explain why such damage isn’t always repaired…. view more
Credit: Image collage courtesy of Dong Wang, UC San Diego
Damage to DNA is a constant threat to cellular life, and so it is constantly monitored and detected by a family of enzymes called RNA polymerases, resulting in subsequent repair to maintain genome integrity. In a paper published this week in the journal PNAS, researchers at University of California San Diego School of Medicine, with colleagues in Spain and Finland, describe for the first time how one type of RNA polymerase gets stalled by DNA lesions caused by exposure to ultraviolet (UV) light.
Called thymine dimers, DNA lesions are damage sites to the base pairs that comprise the structure of DNA. The DNA lesions are caused by exposure to UV light, such as sunlight, which causes neighboring thymine base pairs to bond, disrupting the DNA strand. Untreated, these lesions may eventually result in cancerous growths, such as melanoma.
RNA polymerase I (Pol I) is an enzyme responsible for up to 60 percent of total transcriptional activity
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