1. PIWI-interacting RNAs (piRNAs) are small non-coding RNAs that play essential roles in germ line development and maintaining the integrity of the germ line genome.
2. PIWI-piRNA complexes silence transposable elements and regulate protein-coding genes, contributing to the regulation of gene expression.
3. Recent studies have expanded our understanding of piRNA biogenesis and function, revealing emerging roles of piRNAs in germ line development, infertility, cancer, and neurological diseases in humans.