title: The comprehensive epigenome map of piRNA clusters.
abstract: PIWI-interacting RNA (piRNA) clusters act as anti-transposon/retrovirus centers. Integration of selfish jumping elements into piRNA clusters generates de novo piRNAs, which in turn exert trans-silencing activity against these elements in animal gonads. To date, neither genome-wide chromatin modification states of piRNA clusters nor a mode for piRNA precursor transcription have been well understood. Here, to understand the chromatin landscape of piRNA clusters and how piRNA precursors are generated, we analyzed the transcriptome, transcription start sites (TSSs) and the chromatin landscape of the BmN4 cell line, which harbors the germ-line piRNA pathway. Notably, our epigenomic map demonstrated the highly euchromatic nature of unique piRNA clusters. RNA polymerase II was enriched for TSSs that transcribe piRNA precursors. piRNA precursors possessed 5'-cap structures as well as 3'-poly A-tails. Collectively, we envision that the euchromatic, opened nature of unique piRNA clusters or piRNA cluster-associated TSSs allows piRNA clusters to capture new insertions efficiently.
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi, Tokyo, Japan. kawaokashinpei@gmail.com
authors.forename: Shinpei
authors.initials: S
authors.lastname: Kawaoka
authors.forename: Kahori
authors.initials: K
authors.lastname: Hara
authors.forename: Keisuke
authors.initials: K
authors.lastname: Shoji
authors.forename: Maki
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Toru
authors.initials: T
authors.lastname: Shimada
authors.forename: Sumio
authors.initials: S
authors.lastname: Sugano
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Tomari
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Susumu
authors.initials: S
authors.lastname: Katsuma
mesh_terms: D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D044127:Epigenesis, Genetic; D006657:Histones / Q000378:metabolism; D012322:RNA Precursors / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000096:biosynthesis* / Q000235:genetics; D024363:Transcription Initiation Site; D059467:Transcriptome
chemical_list: D002843:Chromatin; D006657:Histones; D012322:RNA Precursors; D034741:RNA, Small Interfering