Graduate School of Frontier Biosciences, Osaka University

Japanese

Nuclear formation induced by DNA-conjugated beads in living fertilised mouse egg

Journal Sci Rep 9, 8461 (2019)
Authors Yuka Suzuki (1), Şükriye Bilir (2, 3), Yu Hatano (1), Tatsuhito Fukuda (1), Daisuke Mashiko (1), Shouhei Kobayashi (2), Yasushi Hiraoka (2, 3), Tokuko Haraguchi (2, 3), Kazuo Yamagata (1)
  1. Faculty of Biology-Oriented Science and Technology (BOST), Kindai University, Nishimitani 930, Kinokawa-shi, Wakayama, 649-6493, Japan
  2. Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
  3. Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
Title Nuclear formation induced by DNA-conjugated beads in living fertilised mouse egg
PubMed 31186495
Laboratory Nuclear Dynamics Group 〈Prof. Hiraoka〉
Abstract Reformation of a functional nucleus at the end of mitosis is crucial for normal cellular activity. Reconstitution approaches using artificial beads in frog egg extracts have clarified the molecules required for nuclear formation in vitro. However, the spatiotemporal regulation of these components, which is required for the formation of a functional nucleus in living embryos, remains unknown. Here we demonstrate that exogenous DNA introduced in the form of DNA-conjugated beads induces the assembly of an artificial nucleus in living mouse cleavage-stage embryos. Live-cell imaging and immunofluorescence studies revealed that core histones and regulator of chromosome condensation 1 (RCC1) assembled on the DNA, suggesting that nucleosomes were formed. Electron microscopy showed that double-membrane structures, partly extended from annulate lamellae, formed around the beads. Nuclear pore complex-like structures indistinguishable from those of native nuclei were also formed, suggesting that this membranous structure resembled the normal nuclear envelope (NE). However, the reconstituted NE had no nuclear import activity, probably because of the absence of Ras-related nuclear protein (Ran). Thus, DNA is necessary for NE reassembly in mouse embryos but is insufficient to form a functional nucleus. This approach provides a new tool to examine factors of interest and their spatiotemporal regulation in nuclear formation.