The Coming of Age for Piwi Proteins

Abstract

Piwi proteins, a subfamily of Argonaute (Ago) proteins, have recently been shown to bind endogenous small RNAs. However, differences between Ago proteins (which bind microRNAs and small interfering RNAs) and Piwi proteins and Piwi-interacting RNAs (piRNAs) suggest novel functions for Piwi proteins. Here, we highlight the recent progress in understanding Piwi function and the implications for germline and stem cell development. © 2007 Elsevier Inc. All rights reserved.