What happens to skin cells when exposed to UV radiation?

What happens to skin cells when exposed to UV radiation?

• A. They die immediately.
• B. They stop dividing.
• C. They produce new mitochondria.
• D. They activate transcription factors that increase melanin production.

Answer: (D)

When skin is exposed to UV radiation, the body’s first protective response is to increase melanin production in the epidermis. Melanin, the pigment that gives skin its color, absorbs and dissipates UV light, helping to shield skin cell DNA from damage. This adjustment happens through signaling that activates transcription factors—especially MITF—that turn on the genes for melanogenic enzymes like tyrosinase. Tyrosinase drives the chemical steps that make melanin, and the pigment is then transferred from melanocytes to nearby keratinocytes, darkening the skin in a process we call tanning. This change takes hours to days because it relies on new gene expression rather than an immediate structural shift. While UV damage can also trigger cell cycle arrest or apoptosis in severely damaged cells, the described effect specifically highlights the transcription-factor–controlled increase in melanin production as the protective response.

When skin is exposed to UV radiation, the body’s first protective response is to increase melanin production in the epidermis. Melanin, the pigment that gives skin its color, absorbs and dissipates UV light, helping to shield skin cell DNA from damage. This adjustment happens through signaling that activates transcription factors—especially MITF—that turn on the genes for melanogenic enzymes like tyrosinase. Tyrosinase drives the chemical steps that make melanin, and the pigment is then transferred from melanocytes to nearby keratinocytes, darkening the skin in a process we call tanning. This change takes hours to days because it relies on new gene expression rather than an immediate structural shift. While UV damage can also trigger cell cycle arrest or apoptosis in severely damaged cells, the described effect specifically highlights the transcription-factor–controlled increase in melanin production as the protective response.