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Understanding DNA Repair Mechanisms and Their Implications for Aging and Cancer

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The Nobel Prize in Chemistry was awarded in 2015 to three masters of DNA repair mechanisms. Their research helps us understand how DNA maintains its integrity, allowing cells to function properly. Understanding how to repair DNA mutations is a crucial step in the fields of anti-aging and anti-cancer.

DNA is composed of four major bases – A, T, G, and C. Two base pairs can form stable hydrogen bonds: A-T and G-C. This is because of their structural complementarity; other combinations, such as A-G, T-T, lack this complementarity and cannot form stable hydrogen bonds. Environmental factors, such as UV radiation and smoking, can damage DNA.

One of the Nobel laureates, Aziz Sancar, discovered that UV radiation causes T and T to stick together inappropriately, damaging their original function. He first discovered a DNA self-repair mechanism in bacteria, then found related mechanisms in humans. An enzyme called Exinuclease in the cells can detect this T-T mismatch and remove twelve adjacent bases. After the gap is cut out, the DNA polymerase replaces the missing base, which is then sealed by DNA ligase. The entire process is like a factory robot: once it detects a defective product, it is immediately removed and replaced with a new one.

What are the consequences of lacking this repair mechanism? One rare disease – Xeoderma Pigmentosa – occurs when there is a problem with DNA repair mechanisms. When the patient’s skin is exposed to UV radiation and damaged, the DNA cannot repair itself, increasing the risk of cancer. Most patients can only live up to the age of 20.

Does having a repair mechanism mean that cells are not afraid of DNA damage? When the skin is exposed to long-term UV radiation, DNA is continuously damaged. Although this mechanism can repair it, there are still occasional mistakes. Accumulated DNA mutations can cause the skin to age and even develop into cancer cells.

In the near future, it is believed that this DNA repair mechanism can be used to treat cancer. With a little more imagination, can there be a treatment that can restore aging skin to its youthful condition? This way, most skin aging problems, such as wrinkles, blemishes, and sagging, can be treated without laser, radiofrequency, and other therapies. I wonder how long it will take to achieve this?