Associate Professor, Department of Biological Information
PhD 1991, Nagoya University
Office: Room835, B2 building, Suzukakedai campus
Areas of Research: Zoology, Chronobiology, Reproductive biology.
Keywords: Jellyfish, Water flea, Photoperiodism, Germ cell, Oogenesis.
In animals that lack a haploid generation, meiosis must be immediately followed by fusion of the gamete nuclei. Precise temporal coordination between meiosis and fertilization is required for reproducing the next generation. We use starfish oocytes, eggs and embryos to elucidate regulation of meiotic and early mitotic cell cycles. We have found that the Mos-MAPK (mitogen-activated protein kinase)-Rsk (ribosomal protein S6-kinase) cascade prevents spontaneous initiation of development in unfertilized starfish eggs.
In addition, we compare molecular mechanisms of the cell cycle regulation in starfish and many other organisms including jellyfish (Cnidaria), sawfly (Arthropod) and ascidian (Chordata) to look for general principles that underlie a variety of regulatory mechanisms, and to reveal how they are formed in the course of evolution.
- Arakawa, M., Takeda, N.., Tachibana, K, and Deguchi, R. Polyspermy block in jellyfish eggs: Collaborative controls by Ca2+and MAPK. Developmental Biology 392, 80-92. (2014)
- Ucar, H., Tachibana, K., *Kishimoto, T. The Mos-MAPK pathway regulates Diaphanous-related formin activity to drive cleavage furrow closure during polar body emission in starfish oocytes. Journal of Cell Science 126, 5153-5165, (2013)
- Morino, Y., Koga, H., Tachibana K., Shoguchi, E., Kiyomoto, M., and *Wada, H. Heterochronic Activation of VEGF Signaling and the Evolution of the Skeleton in Echinoderm Pluteus Larvae. Evolution and Development 14, 428-436, (2012)
- Sensui, N., *Yoshida, M., and Tachibana, K. Role of Mos/MEK/ERK cascade and Cdk1 in Ca2+ oscillations in fertilized ascidian eggs. Developmental Biology 367, 208-215. (2012)
- Tachibana, K., Mori, M., Matsuhira, T., Karino, T., Inagaki, T., Nagayama, A., Nishiyama, A., Hara, M., and *Kishimoto, T. Initiation of DNA replication after fertilization is regulated by p90Rsk at pre-RC/pre-IC transition in starfish eggs. Proc Natl Acad Sci USA.107, 5006-5011, (2010)
- Hara M, Mori M, Wada T, Tachibana K, *Kishimoto T. Start of the embryonic cell cycle is dually locked in unfertilized starfish eggs. Development 136, 1687-1696. (2009)
- Tachibana K, Hara M, Hattori Y, *Kishimoto T. Cyclin B-Cdk1 controls pronuclear union in interphase. Curr Biol. 18, 1308-1313. (2008)
- Mori M, Hara M, Tachibana K, *Kishimoto T. p90Rsk is required for G1 phase arrest in unfertilized starfish eggs. Development 133, 1823-1830. (2006)
- Okano-Uchida T, Okumura E, Iwashita M, Yoshida H, Tachibana K, *Kishimoto T. Distinct regulators for Plk1 activation in starfish meiotic and early embryonic cycles. EMBO J. 22, 5633-5642. (2003)
- Okumura E, Fukuhara T, Yoshida H, Hanada S, Kozutsumi R, Mori M, Tachibana K, *Kishimoto T. Akt inhibits Myt1 in the signalling pathway that leads to meiotic G2/M-phase transition. Nature Cell Biol. 4, 111-116. (2002)
- Tachibana K, Tanaka D, Isobe T, *Kishimoto T. c-Mos forces the mitotic cell cycle to undergo meiosis II to produce haploid gamates. Proc Natl Acad Sci USA. 97, 14301-14306. (2000)
- Nishiyama A, Tachibana K, Igarashi Y, Yasuda H, Tanahashi N, Tanaka K, Ohsumi K, *Kishimoto T. A non-proteolytic function of the proteasome is required for the dissociation of Cdc2 and cyclin B at the end of M-phase. Genes Dev. 14, 2344-2457. (2000)