Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure.
Saved in:
| Title: | Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure. |
|---|---|
| Authors: | Premi, Sanjay, Wallisch, Silvia, Mano, Camila M., Weiner, Adam B., Bacchiocchi, Antonella, Wakamatsu, Kazumasa, Bechara, Etelvino J. H., Halaban, Ruth, Douki, Thierry, Brash, Douglas E. |
| Source: | Science (pre-March 2025). 2/20/2015, Vol. 347 Issue 6224, p842-847. 6p. |
| Subjects: | Chemiexcitation, Melanins, Physiological effects of ultraviolet radiation, Reactive oxygen species, Dimers, Cyclobutane, Pyrimidines, Melanoma, Genetics |
| Abstract: | Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPDs), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. We found that in melanocytes, CPDs are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These "dark CPDs" constitute the majority of CPDs and include the cytosine-containing CPDs that initiate UV-signature C→T mutations. Dark CPDs arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but induces CPDs by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically generated excited electronic states are relevant to mammalian biology. [ABSTRACT FROM AUTHOR] |
| Copyright of Science (pre-March 2025) is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
Be the first to leave a comment!
