Small noncoding RNAs in the germline

Abstract

Small noncoding RNAs have emerged as potent regulators of gene expression, especially in the germline.We reviewthe biogenesis and regulatory function of three major small noncoding RNA pathways in the germline: The small interfering RNA (siRNA) pathway that leads to the degradation of target mRNAs, the microRNA (miRNA) pathway that mostly represses the translation of target mRNAs, and the newly discovered Piwi-interacting RNA (piRNA) pathway that appears to have diverse functions in epigenetic programming, transposon silencing, and the regulation of mRNA translation and stability. The siRNA and miRNA pathways are present in the germline aswell as many somatic tissues,whereas the piRNApathway is predominantly confined to the germline. Investigation of the three smallRNA pathways has started to reveal a new dimension of gene regulation with defining roles in germline specification and development. © 2011 Cold Spring Harbor Laboratory Press.