title: Fighting an old war with a new weapon--silencing transposons by Piwi-interacting RNA.
abstract: Discovered six decades ago, transposons are known to selfishly multiply within and between chromosomes. Although they may play a creative role in building new functional parts of the genome, transposons usually cause insertional mutagenesis and/or turn nearby genes on or off. To maintain genome integrity, cells use a variety of strategies to defend against the proliferation of transposons. A class of small noncoding RNA, discovered seven years ago and called piRNA, is a new player in the war to silence transposons. piRNA is made via two biogenesis pathways: the primary processing pathway and the ping-pong amplification loop. These pathways are critically involved in transposon RNA degradation, DNA methylation, and histone modification machinery that represses transposons. In this review, we briefly introduce transposon-caused genomic instability and summarize our current understanding of the piRNA pathway, focusing on its key function in transposon silencing.
authors.affiliation: Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Manhong
authors.initials: M
authors.lastname: Guo
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000818:Animals; D019175:DNA Methylation; D004251:DNA Transposable Elements / Q000235:genetics*; D015894:Genome, Human; D042822:Genomic Instability; D006657:Histones / Q000378:metabolism; D006801:Humans; D011499:Protein Processing, Post-Translational; D034622:RNA Interference; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D006657:Histones; D034741:RNA, Small Interfering
keywords: Piwi; Piwi-interacting RNA; genomic instability; helicase; nuclease; transposon