Laboratory of Cellular Structure and Function



Associate Professor

Molecular Cell Biology


National Institute of Information and Communications Technology


Advanced ICT Research Institute Kobe

Research Theme

This laboratory is studying functional organization of the cell nucleus using mammalian and fission yeast cells. Toward this end, we have developed the computer-controlled microscope system that is capable of recording living fluorescently-stained cells.

Chromosome organization in fission yeast meiosis

We have found that telomeres and centromeres greatly change their nuclear positions upon entering meiosis. This phenomenon has been confirmed in a wide variety of eukaryotes from yeasts to humans. We are now trying to understand molecular mechanisms for such nuclear reorganization during meiosis.

Dynamic organization of the nuclear structures in mammalian cells

We are trying to understand how the cell nucleus is organized to achieve their functions. The nucleus provides a physical framework for gene expression. We are examining molecular and structural bases for nuclear functions with a special interest in chromosome dynamics, chromosome-nuclear membrane interactions and in nuclear membrane dynamics during the progression through mitosis.

Dynamic organization of the nuclear structures in Tetrahymena

The ciliated protozoa have two functionally and structurally distinct nuclei in a single cell. A somatic macronucleus (MAC) is transcriptionally active while a germ line micronucleus (MIC) is inert during vegetative growth. We are examining molecular and structural bases of such “nuclear dimorphism”

0Molecular basis of telomere clustering in fission yeast meiosis.

1Dynamic behavior of nuclear structures in human cells during cell division. Chromosomes (blue), centromeres (red), and microtubules (green).

2Binucleated ciliated protozoa, Tetrahymena thermophila. Chromosomes in macronucleus (middle) and micronucleus (left) were stained by Heochst 33342 (green).


Asakawa H, Yang HJ, Yamamoto TG, Ohtsuki C, Chikashige Y, Sakata-Sogawa K, Tokunaga M, Iwamoto M, Hiraoka Y, Haraguchi T. Characterization of nuclear pore complex components in fission yeast Schizosaccharomyces pombe Nucleus 5 , (2014)

Ding DQ , Okamasa K, Yamane M, Tsutsumi C, Haraguchi T, Yamamoto M, and Hiraoka Y. Meiosis-specific non-coding RNA mediates robust pairing of homologous chromosomes in meiosis.mere function in fission yeast. Science 336 , 732 - 736 (2012)

Hiraoka Y, Maekawa H, Asakawa H, Chikashige Y, Kojidani T, Osakada H, Matsuda A, Haraguchi T. Inner nuclear membrane protein Ima1 is dispensable for intranuclear positioning of centromeres. Genes Cells 10 , 1000 - 1011 (2011)

Asakawa H., Kojidani T,. Mori, C., Osakada H., Sato M., Ding D.-Q. Hiraoka Y., Haraguchi, T. Virtual breakdown of the nuclear envelope in fission yeast meiosis. Curr. Biol. 20 , 1919 - 1925 (2010)

Hiraoka Y, Dernburg AF. The SUN Rises on Meiotic Chromosome Dynamics. Developmental Cell 17(5) , 598 - 605 (2009)

Chikashige Y, Yamane M, Okamasa K, Tsutsumi C, Kojidani T, Sato M, Haraguchi T, Hiraoka Y. Membrane proteins Bqt3 and Bqt4 anchor telomeres to the nuclear envelope to ensure chromosomal bouquet formation. J. Cell Biol. 187 , 413 - 427 (2009)

Iwamoto M, Mori C, Kojidani T, Bunai F, Hori T, Fukagawa T, Hiraoka Y, and Haraguchi T. Nup98 nucleoporins bearing different types of repeat sequence characterize nucleus-specific nuclear pore complexes in the ciliate Tetrahymena. Curr. Biol. 19 , 843 - 847 (2009)

Hiraoka Y, Kawamata K, Haraguchi T and Chikashige Y. Codon usage bias is correlated with gene expression levels in the fission yeast Schizosaccharomyces pombe. Genes Cells 14 , 499 - 509 (2009)

Haraguchi T, Kojidani T, Koujin T, Shimi T, Osakada H, Mori C, Yamamoto A, and Hiraoka Y. Live cell imaging and electron microscopy revealed dynamic processes of BAF-directing nuclear envelope assembly. J. Cell Sci. 121 , 2540 - 2554 (2008)

Chikashige, Y., Tsutsumi, C., Yamane, M., Okamasa, K., Haraguchi, T., and Hiraoka, Y. Meiotic proteins Bqt1 and Bqt2 tether telomeres to form the bouquet arrangement of chromosomes. Cell 125 , 59 - 69 (2006)


Tokuko Haraguchi
Advanced ICT Research Institute Kobe
National Institute of Information and Communications Technology
588-2 Iwaoka, Iwaoka-cho, Nishi-ku
Kobe 651-2492, Japan
Tel: 81-78-969-2241, Fax: 81-78-969-2249