RNA short strand protects against bacteria

New York -- U.S. scientists have found a short RNA strand -- microRNA-203 -- helps exposed skin cells protect the body from bacteria, dehydration and cancer.

The Rockefeller University researchers said they discovered microRNA-203 helps build a tough protective barrier by repressing the activity of a molecule called p63.

Hundreds of the tiny RNA molecules are expressed in skin. "But there was something curious about one in particular, microRNA-203," said postdoctoral researcher Rui Yi, who led the study with Elaine Fuchs, head of the university's Laboratory of Mammalian Cell Biology and Development, and Professor Rebecca Lancefield.

MicroRNA, discovered in mammals in 2001, regulate genes outside of the cell's nucleus.

The researchers found during the 13th day of development, mouse skin is primarily composed of undifferentiated stem cells. Two days later, those stem cells exit the inner layer of the skin and begin to differentiate into cells that form the outermost, protective layer. MicroRNA-203's expression skyrockets precisely during that period, suggesting it plays some key role in
the barrier's development, the researchers said.

The study is reported in the journal Nature.

Copyright 2008 by United Press International.