Get access

Histone H3 is absent from organelle nucleoids in BY-2 cultured tobacco cells

Authors

  • Mari Takusagawa,

    1. Department of Biological Science and Environment, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoya-nishi-machi, Nara, Japan
    Search for more papers by this author
  • Satoshi Tamotsu,

    1. Department of Biological Science and Environment, Graduate School of Humanities and Sciences, Nara Women's University, Kitauoya-nishi-machi, Nara, Japan
    Search for more papers by this author
  • Atsushi Sakai

    Corresponding author
    • Faculty of Science, Department of Biological Sciences, Nara Women's University, Kitauoya-nishi-machi, Nara, Japan
    Search for more papers by this author

Corresponding author: e-mail: sakai@cc.nara-wu.ac.jp

Abstract

The core histone proteins (H2A, H2B, H3 and H4) are nuclear-localised proteins that play a central role in the formation of nucleosome structure. They have long been considered to be absent from extra-nuclear, DNA-containing organelles; that is plastids and mitochondria. Recently, however, the targeting of core histone H3 to mitochondria, and the presence of nucleosome-like structures in mitochondrial nucleoids, were proposed in cauliflower and tobacco respectively. Thus, we examined whether histone H3 was present in plant organelles and participated in the organisation of nucleoid structure, using highly purified organelles and organelle nucleoids isolated from BY-2 cultured tobacco cells. Immunofluorescence microscopic observations and Western blotting analyses demonstrated that histone H3 was absent from organelles and organelle nucleoids, consistent with the historical hypothesis. Thus, the organisation of organelle nucleoids, including putative nucleosome-like repetitive structures, should be constructed and maintained without participation of histone H3.

Ancillary