Piwi Nuclear Localization and Its Regulatory Mechanism in Drosophila Ovarian Somatic Cells

Ryu Yashiro, Yukiko Murota, Kazumichi M. Nishida, Haruna Yamashiro, Kaede Fujii, Asuka Ogai, Soichiro Yamanaka, Lumi Negishi, Haruhiko Siomi, Mikiko C. Siomi

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In Drosophila ovarian somatic cells (OSCs), Piwi represses transposons transcriptionally to maintain genome integrity. Piwi nuclear localization requires the N terminus and PIWI-interacting RNA (piRNA) loading of Piwi. However, the underlying mechanism remains unknown. Here, we show that Importinα (Impα) plays a pivotal role in Piwi nuclear localization and that Piwi has a bipartite nuclear localization signal (NLS). Impα2 and Impα3 are highly expressed in OSCs, whereas Impα1 is the least expressed. Loss of Impα2 or Impα3 forces Piwi to be cytoplasmic, which is rectified by overexpression of any Impα members. Extension of Piwi-NLS with an additional Piwi-NLS leads Piwi to be imported to the nucleus in a piRNA-independent manner, whereas replacement of Piwi-NLS with SV40-NLS fails. Limited proteolysis analysis suggests that piRNA loading onto Piwi triggers conformational change, exposing the N terminus to the environment. These results suggest that Piwi autoregulates its nuclear localization by exposing the NLS to Impα upon piRNA loading. Piwi represses transposons transcriptionally to maintain genome integrity. Yashiro et al. show that Importinα plays a pivotal role in Piwi nuclear localization and that Piwi has a bipartite nuclear localization signal at the N terminus. Piwi autoregulates its nuclear localization by exposing the nuclear localization signal to Impα upon piRNA loading.

Original languageEnglish
Pages (from-to)3647-3657
Number of pages11
JournalCell Reports
Volume23
Issue number12
DOIs
Publication statusPublished - 2018 Jun 19

Keywords

  • Drosophila
  • Importin
  • nuclear import
  • nuclear localization signal
  • piRNA
  • PIWI

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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    Yashiro, R., Murota, Y., Nishida, K. M., Yamashiro, H., Fujii, K., Ogai, A., Yamanaka, S., Negishi, L., Siomi, H., & Siomi, M. C. (2018). Piwi Nuclear Localization and Its Regulatory Mechanism in Drosophila Ovarian Somatic Cells. Cell Reports, 23(12), 3647-3657. https://doi.org/10.1016/j.celrep.2018.05.051