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The Mechanism of DNA Damage by UV Radiation

  News Medical Life Sciences, By Supriya Subramanian, PhD, 10 Apr 18

Solar ultraviolet radiation (UV) exposure triggers DNA damage, a preliminary step in the process of carcinogenesis. 

The stability of DNA is extremely important for the proper functioning of all cellular processes. Exposure to UV radiation alters the structure of DNA, affecting the physiological processes of all living systems ranging from bacteria to humans.

Ultraviolet Radiation

Natural sunlight stimulates the production of vitamin D, an important nutrient for the formation of healthy bones. However, sunlight is also a major source of UV radiation. Individuals who get excessive UV exposure are at a great risk of developing skin cancers. There are three types of UV rays: UVA, UVB and UVC.

• UVC rays (100-280 nm) are the most energetic and damaging of the three rays. Fortunately, UVC is absorbed by the ozone layer before reaching the earth’s surface.
• UVA rays (315-400 nm) possess the lowest energy and is able to penetrate deep into the skin. Prolonged exposure has been linked to ageing and wrinkling of the skin. UVA is also the main cause of melanomas.
• UVB rays (280-315 nm) possess higher energy than UVA rays and affect the outer layer of the skin leading to sunburns and tans. Basal cell carcinoma and squamous cell carcinoma are caused by UVB radiation.

DNA Damage by UV Radiation

DNA is composed of two complementary strands that are wound into a double helix. The hereditary message is chemically coded and made up of the four nucleotides adenine (A), thymine (T), guanine (G) and cytosine (C).  UVB light interferes directly with the bonding between the nucleotides in the DNA. ……….

https://www.news-medical.net/life-sciences/The-Mechanism-of-DNA-Damage-by-UV-Radiation.aspx

April 11, 2018 - Posted by Christina Macpherson | radiation, Reference