We know how that sounds, but do yourself a favor and read on: Just several hours after you’ve been exposed to the sun, your skin will start to change color, and with it come all the other side effects of sunburn, including pain and discomfort.
Why does this happen? If only our skin changed color immediately after excessive exposure, we might be able to reduce our time in the sun and protect ourselves from unpleasant side effects.
A new study conducted in collaboration with researchers from Tel Aviv University, Wolfson Medical Center, the Weizmann Institute of Science, the University of California and the University of Paris-Saclay, led by Prof. Carmit Levy and PhD candidate Nadav Elkoshi from the Department of Molecular Genetics and Biochemistry at the Tel Aviv University School of Medicine, reveals the reason for this counterintuitive phenomenon.
“We were able to find out why the tanning phenomenon does not occur immediately when the body is exposed to the sun, but rather after a certain delay. It turns out that the DNA repair mechanism takes precedence over all other systems in the cell and temporarily suppresses the pigmentation mechanism.”
Elkoshi explains that “we have two mechanisms designed to protect the skin from harmful UV radiation. The first mechanism repairs the DNA in skin cells that have been affected by radiation. The second mechanism is increased production of melanin, which darkens the skin to protect it from future radiation exposure – and that is essentially a tan.
“In our research, we were able to find out why the tanning phenomenon does not occur immediately when the body is exposed to the sun, but rather after a certain delay. It turns out that the DNA repair mechanism takes precedence over all other systems in the cell and temporarily suppresses the pigmentation mechanism. Only after cells have repaired the genetic information to the best of their ability, do they start producing melanin in an enhanced way.”
The professor. Levy added that “the most important thing is to protect the genetic information from mutations, which is why the DNA repair mechanism takes priority inside the cell during exposure to sun radiation. In our previous research, we have shown that a protein called MITF, which is active during exposure, is the regulator of the skin’s two protective mechanisms.
Here we demonstrate that a protein called ATM, which plays a key role in DNA repair, activates the repair mechanism and temporarily suppresses the pigmentation mechanism, in order to maximize the cell’s chances of surviving without mutations after radiation exposure. Our theory is that one system silences the other until repair reaches its peak, which is a few hours after radiation exposure, and only then does the pigment-producing mechanism kick in.”
