Mar. 5, 2008 Exposed skin cells weather conditions harsh enough
to mutate DNA. To keep these mutations from spreading, evolution
has found a way to keep these cells from proliferating.
Rockefeller University and HHMI researchers have now discovered
evolution's solution: a tiny strand of RNA. But the research's
implications go deeper, and may also suggest how healthy cells
elsewhere in the body can turn cancerous. Every minute, 30,000
of our outermost skin cells die so that we can live. When they
do, new cells migrate from the inner layer of the skin to the
surface of it, where they form a tough protective barrier. In a
series of elegant experiments in mice, researchers at
Rockefeller University have now discovered a tiny RNA molecule
that helps create this barrier. The results not only yield new
insight into how skin first evolved, but also suggest how
healthy cells can turn cancerous. Hundreds of these tiny RNA
molecules, called microRNAs, are expressed in skin, "But there
was something curious about one in