New Protein Pmn34 with an Exonuclease Motif Localizes in the Mitochondrial Nucleoid Periphery of Physarum polycephalum

Kie Itoh; Akiko Izumi; Toshiyuki Mori; Naoshi Dohmae; Ryoko Yui; Katsura Maeda-Sano; Masahiro M. Kanaoka; Haruko Kuroiwa; Tsuneyoshi Kuroiwa; Tetsuya Higashiyama; Kimiko Murakami-Murofushi; Shigeyuki Kawano; Narie Sasaki

doi:10.1508/cytologia.74.401

New Protein Pmn34 with an Exonuclease Motif Localizes in the Mitochondrial Nucleoid Periphery of Physarum polycephalum

Kie Itoh, Akiko Izumi, Toshiyuki Mori, Naoshi Dohmae, Ryoko Yui, Katsura Maeda-Sano, Masahiro M. Kanaoka, Haruko Kuroiwa, Tsuneyoshi Kuroiwa, Tetsuya Higashiyama, Kimiko Murakami-Murofushi, Shigeyuki Kawano, Narie Sasaki

Author information

Kie Itoh
Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo
Division of Biological Science, Graduate School of Science, Nagoya University
Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo
Akiko Izumi
Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo
Toshiyuki Mori
Miyagishima Initiative Research Unit, Advanced Science Institute, RIKEN
Naoshi Dohmae
Biomolecular Characterization Team, Advanced Science Institute, RIKEN
Ryoko Yui
Division of Biological Science, Graduate School of Science, Nagoya University
Katsura Maeda-Sano
Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo
Masahiro M. Kanaoka
Division of Biological Science, Graduate School of Science, Nagoya University
Haruko Kuroiwa
Research Information Center for Extremophiles, Graduate School of Science, Rikkyo (St. Paul's) University
Tsuneyoshi Kuroiwa
Research Information Center for Extremophiles, Graduate School of Science, Rikkyo (St. Paul's) University
Tetsuya Higashiyama
Division of Biological Science, Graduate School of Science, Nagoya University
Kimiko Murakami-Murofushi
Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo
Shigeyuki Kawano
Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo
Narie Sasaki
Division of Biological Science, Graduate School of Science, Nagoya University
Department of Biology, Faculty of Science, Ochanomizu University, Bunkyo

Keywords: Mitochondrial DNA (mtDNA), Mitochondrial nucleoid (mt-nucleoid), Physarum polycephalum, “DEDD” superfamily exonuclease motif

JOURNAL OPEN ACCESS

2009 Volume 74 Issue 4 Pages 401-407

DOI https://doi.org/10.1508/cytologia.74.401

Details

Abstract

Mitochondrial DNA (mtDNA) is highly organized into a compact structure, the mitochondrial nucleoid (mt-nucleoid). To facilitate our understanding of the regulation of mtDNA genetic activity within the mt-nucleoid structure, we have identified a novel mt-nucleoid protein Pmn34 (Physarum polycephalum mitochondrial nucleoid protein 34), having a molecular weight of 34 kDa, from pure mt-nucleoids isolated from the true slime mold, Physarum polycephalum. The Pmn34 protein is composed of 326 amino acids with mitochondrial transit peptides and its primary sequence contains a conserved 3′ to 5′ exonuclease motif of the “DEDD” superfamily. DNA mobility shift assays demonstrated that recombinant Pmn34 binds weakly to both mtDNA and λDNA with no apparent sequence specificity. Furthermore, immunoblotting and immunostaining analyses revealed that Pmn34 localizes specifically in the peripheral region of mt-nucleoids. These results indicate that Pmn34 functions in the peripheral region of mt-nucleoids, suggesting that the mt-nucleoid is compartmentalized into functional domains.

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