Chief Scientist Laboratories Chromosome Dynamics Laboratory

Chief Scientist: Tatsuya Hirano (Ph.D.)

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Research Summary

The duplication and segregation of the genome are two of the most fundamental events in cell reproduction. Our laboratory is interested in understanding the molecular mechanisms that regulate the faithful segregation of chromosomes during mitosis. By using a cell-free extract derived from Xenopus laevis (African toad) eggs, we have discovered two multiprotein complexes, condensin and cohesin, that play central roles in chromosome condensation and sister chromatid cohesion, respectively. At the heart of the two complexes lie members of a large family of chromosomal ATPases, the SMC (structural maintenance of chromosomes) family. Accumulating lines of evidence suggest that SMC proteins actively participate in many aspects of higher-order chromosome dynamics, including chromosome-wide gene regulation, DNA recombination /repair and meiotic chromosome segregation. The long-term goal in our laboratory is to understand how condensin and cohesin work at a mechanistic level in vitro, and how they interact with other proteins to execute their essential functions in vivo. We take multidisciplinary approaches toward this goal, including biochemistry, cell biology, structural biology and biophysics. Our research will contribute to a better understanding of human health because chromosome anomalies, such as aneuploidy and translocations, are tightly associated with tumor development and birth defects.

Main Research Fields

Biology & Biochemistry

Related Research Fields

Molecular Biology & Genetics

Research Subjects

Chromosome architecture and segregation
Molecular mechanisms of action of SMC protein complexes
Chromosome dynamics and human disease

Selected Publications

1. Hara, K., Kinoshita, K., Migita, T., Murakami, K., Shimizu, K., Takeuchi, K., Hirano, T., Hashimoto, H.:
"Structural basis of HEAT-kleisin interactions in the human condensin I subcomplex."
EMBO Rep. 20, e47183 (2019).
2. Sakai Y., Mochizuki, A., Kinoshita, K., Hirano, T., Tachikawa, M.:
"Modeling the functions of condensin in chromosome shaping and segregation."
PLoS Comp. Biol. 14(6), e1006152 (2018).
3.Shintomi, K., and Hirano, T.:
“Mitotic chromosome assembly in vitro: functional cross talk between nucleosomes and condensins.”
Cold Spring Harbor Symp. Quant. Biol. doi:10.1101/sqb.2017.82.033639 (2017).
4.Shintomi, K., Inoue, F., Watanabe, H., Ohsumi, K., Ohsugi, M., and Hirano, T.:
“Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts.”
Science 356, 1284-1287 (2017).
5.Kamada, K., Su’etsugu, M., Takada, H., Miyata, M., and Hirano, T.:
“Overall shapes of the SMC-ScpB complex are determined by balance between constraint and relaxation of its structural parts.”
Structure 25, 603-616 (2017).
6.Ono, T., Sakamoto, C., Nakao, M., Saitoh, N., and Hirano, T.:
“Condensin II plays an essential role in reversible assembly of mitotic chromosomes in situ.”
Mol. Biol. Cell. 28, 2875-2886 (2017).
7.Kinoshita, K., and Hirano, T.:
“Dynamic organization of mitotic chromosomes.”
Curr. Opin. Cell Biol. 46, 46-53 (2017).
8.Hirano, T.:
“Condensin-based chromosome organization from bacteria to vertebrates.”
Cell 164, 847-857 (2016).
9.Shintomi, K., Takahashi, T. S., and Hirano, T.:
“Reconstitution of mitotic chromatids with a minimum set of purified factors.”
Nat. Cell Biol. 17, 1014-1023 (2015).
10.Kinoshita, K., Kobayashi, T. J., and Hirano, T.:
“Balancing acts of two HEAT subunits of condensin I support dynamic assembly of chromosome axes.”
Dev. Cell 33, 94-106 (2015).

Recent Research Results

Jul. 21, 2017
Making do with less

Annual research report

Lab Members

Principal investigator

Tatsuya Hirano: Chief Scientist

Core members

Takao Ono: Senior Research Scientist
Kazuhisa Kinoshita: Senior Research Scientist
Keishi Shintomi: Senior Research Scientist
Shoji Tane: Postdoctoral Researcher
Makoto Kozai: Postdoctoral Researcher
Yuuki Aizawa: Technical Staff II

Contact Information

2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Email: hiranot [at] riken.jp