title: Piwi-interacting RNAs: biological functions and biogenesis.
abstract: The integrity of the germline genome must be maintained to achieve successive generations of a species, because germline cells are the only source for transmitting genetic information to the next generation. Accordingly, the germline has acquired a system dedicated to protecting the genome from 'injuries' caused by harmful selfish nucleic acid elements, such as TEs (transposable elements). Accumulating evidence shows that a germline-specific subclass of small non-coding RNAs, piRNAs (piwi-interacting RNAs), are necessary for silencing TEs to protect the genome in germline cells. To silence TEs post-transcriptionally and/or transcriptionally, mature piRNAs are loaded on to germline-specific Argonaute proteins, or PIWI proteins, to form the piRISC (piRNA-induced silencing complex). The present chapter will highlight insights into the molecular mechanisms underlying piRISC-mediated silencing and piRNA biogenesis, and discuss a possible link with tumorigenesis, particularly in Drosophila.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan. kaoru@biochem.s.u-tokyo.ac.jp
authors.forename: Kaoru
authors.initials: K
authors.lastname: Sato
authors.forename: Mikiko C
authors.initials: MC
authors.lastname: Siomi
mesh_terms: D000818:Animals; D020868:Gene Silencing; D006801:Humans; D008954:Models, Biological; D009369:Neoplasms / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics; D034741:RNA, Small Interfering / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering