#sun seeking

Scientists already knew the skin tans because it has special cells called keratinocytes that produce the dark pigment melanin and give it to other cells to shield them from DNA damage by ultraviolet (UV) light. But they did not know how UV light kickstarts melanin production in the first place. Dr Cui and colleagues suspected that the whole process starts when UV light triggers the gene p53 into action. They tested this by exposing mice whose keratinocytes lacked p53 to UV light; their skin did not tan. The researchers also explored the possibility that p53 protects the skin against DNA damage in another way - by triggering sun seeking behaviour. Apparently, when people are exposed to UV light, like that of the sun, p53 triggers a process that releases a hormone, b-endorphin, that docks in opiate receptors in brain cells and is linked to feelings of pleasure. According to Dr Fisher, "The number one risk factor for melanoma is an inability to tan; people who tan easily or have dark pigmentation are far less likely to develop the disease." He said that this research shows that p53 "has a powerful role in protecting us against sun damage in the skin."