Laboratory For Chromosome Segregation
Team Leader
Tomoya KITAJIMA (Ph.D.)
Oocytes produce haploid eggs through meiosis, a specialized type of cell division. To form a normal egg, the right number of chromosomes must be transmitted from an oocyte into the egg by chromosome segregation during meiosis. However, the rate of errors in chromosome segregation is known to be extremely high (estimated 10-20%) in mammalian oocytes, and even increases with the maternal age. Most of fertilized eggs produced through such improper segregation quickly dye, and if survived to term, result in severe congenital diseases such as Down syndrome (trisomy 21). Our team studies the mechanism how chromosomes are segregated during meiosis in oocytes, using the mouse as a model. We observe the dynamics of chromosomes and their molecular machineries in live mouse oocytes, taking advantage of our unique techniques in live imaging microscopy. We identify the molecular players for the dynamic behavior and analyze their function in detail by genetic methods available in mice. Furthermore, we aim to understand why chromosome segregation errors are associated with age.
- Analysis of chromsome and spindle dynamics during meioisis in mammalian oocytes
- Functional analysis of proteins responsible for proper chromosome segregation
- Identification of causes of chromosome segregation errors in aged oocytes
- Kitajima, T., S., Ohsugi, M., and Ellenberg, J.:
"Complete kinetochore tracking reveals error-prone homologous chromosome biorientation in mammalian oocytes."
Cell 146, 568-581 (2011). - Lee, J.*, Kitajima, T. S.*, Tanno, Y., Yoshida, K., Morita, T., Miyano, T., Miyake, M., and Watanabe, Y.:
"Unified mode of centromeric protection by shugoshin in mammalian oocytes and somatic cells."
Nature Cell Biology 10, 42-52 (2008). - Kitajima, T. S., Sakuno, T., Ishiguro, K., Iemura, S., Natsume, T., Kawashima, S. A., and Watanabe, Y.:
"Shugoshin collaborates with protein phosphatase 2A to protect cohesin."
Nature 441, 46-52 (2006). - Kitajima, T. S., Hauf, S., Ohsugi, M., Yamamoto, T., and Watanabe, Y.:
"Human Bub1 defines the persistent cohesion site along the mitotic chromosome by affecting shugoshin localization."
Current Biology 15, 353-359 (2005). - Kitajima, T. S., Kawashima, S. A., and Watanabe, Y.:
"The conserved kinetochore protein shugoshin protects centromeric cohesion during meiosis."
Nature 427, 510-517 (2004). - Kitajima, T. S.*, Yokobayashi, S.*, Yamamoto, M., and Watanabe, Y.:
"Distinct cohesin complexes organize meiotic chromosome domains."
Science 300, 1152-1155 (2003).
Principal Investigator
- Tomoya KITAJIMA
- Team Leader
Members
- Shuhei YOSHIDA
- Research Scientist
- Yogo SAKAKIBARA
- Research Associate
- Masako KAIDO
- Technical Staff I