Outline Director's Room Pathology Cell Biology Biochemistry Experimental Pathology Cancer Biology Carcinogenesis Genetic Diagnosis Protein Engineering Epigenetic Carcinogenesis Cancer Genomics Physics Chemotherapy

Fundamental to all the life processes is the ability of cells to divide faithfully. In most eukaryotes, equal partitioning of the genetic material is carried out by forming chromosomes in mitosis. Loss or gain of chromosomes upon cell division is often associated with human cancers. This property called chromosome instability might arise from a lesion in chromosomes segregation machinery. Our ultimate goal is to illustrate the molecular basis for the structure and function of chromosomes in order to provide a connection between chromosome instability and cancer development. [ Figure 1: Structural changes of chromosome during mitosis. HeLa cells were treated with Carnoy fixative and spread chromosomes were stained with Giemsa solution.] The pictures show how chromosomes are formed and segregated during mitosis. In prophase, chromatin is structurally reorganized into condensed chromosomes and become visible as long threads in nucleus. In prometaphase and metaphase, chromosomes are further shortened, and the sister chromatids that each contain one copy of the replicated DNA are partially resolved from each other. In contrast, chromatids remain tightly connected at centromeres where kinetochores assemble that are then captured by spindle microtubules. When all the kinetochores are properly connected to spindles, cells will transit into anaphase when cohesion between sister chromatids is lost and chromatids are segregated towards opposite spindle poles. For accurate chromosome transmission, each of these steps must be accomplished without an error, and any aspects of these processes are important to study. Among them, we would like to focus our attention to the following issues: (1) Mitotic chromosome assembly (2) Structure of centromeres (3) Kinetochore-spindle microtubule interaction (4) Physiology and pathology of mitotic kinases Chief Toru Hirota Senior Staff Technician Youko Hirayama Postdoctoral Scientist Kentaro Takagaki, Kazuhiko Uchida, Norihisa Shindo, Souichi Kurita Visiting PhD Student Satoshi Abe, Yusuke Abe Visiting Undergraduate Student Kota Nagasaka Management Assistant Chizuko Fujiya ATTENTION: Positions available for attending associate member.