In eukaryotic mitosis, duplicated chromosomes are segregated to daughter cells by a microtubule-based bipolar structure, the mitotic spindle. Proper assembly and functions of the bipolar spindle is essential to maintain genomic information. On the other hand, mitotic spindle positioning within mother cells helps to determine the size, location, and polarity of daughter cells, which contribute to cellular differentiation and tissue morphogenesis during development of multi-cellular organisms. Key conserved genes required for mitotic spindle assembly and positioning have been identified, especially in somatic cell models. However, detailed mechanisms of their spatiotemporal regulation are still unclear. In addition, considering the unique features of early embryonic division, such as large cell size, it remains unclear whether the somatic cell-based model can be applied to large, vertebrate embryonic cells.

In the Cell Division Dynamics Unit, we have been studying mechanisms of spindle assembly, positioning, and remodeling using advanced cell biological technologies in cultured human cells and medaka fish embryos to better understand the basis and adaptability of cell division mechanisms in vertebrate early embryogenesis.