New class of small RNAs found

Piwi-interacting, or piRNAs, may play a role in developing sperm in mice

Charles Q. Choi
Jun 4, 2006
A newly revealed class of thousands of distinct small RNA molecules in mammals is common in developing mouse sperm, two research teams report in the June 4 online edition of Nature.Although the presence of these piRNAs in developing sperm suggests they play essential roles during the complex process of gamete formation, their genesis and function remain unclear. "If our experience with piRNAs is anything like that with microRNAs, you'll see a wave of discovery from a lot of people following up on these unknowns," study author Thomas Tuschl at Rockefeller University in New York told The Scientist.The researchers investigated Piwi proteins, which are important in germ cell development in invertebrates and mice. These molecules make up a subgroup within the Argonaute proteins, which microRNAs target to silence genes.Both groups purified, cloned and sequenced RNAs associated with mouse testes immunoprecipitates of ribonucleoprotein complexes incorporating a Piwi protein. Tuschl...