During development of multi-cellular organisms, a fertilized egg undergoes repeated cell division called mitosis. In mitosis, a microtubule-based mitotic spindle is assembled and accurately segregates duplicated chromosomes to daughter cells to maintain genomic information. In addition, mitotic spindle positioning helps determine the size, location, and polarity of daughter cells, which contribute to cellular differentiation and tissue morphogenesis during development. Key conserved genes required for mitotic spindle assembly and positioning have been identified and carefully studied using somatic cell models. However, their precise mechanisms are still unclear at the molecular level and in developmental contexts. In addition, considering unique features of early embryos such as larger cell size, early embryonic cells may have developed specialized mechanisms for spindle assembly and positioning.
In the Cell Division Dynamics Unit, we are studying the mechanisms of mitotic spindle assembly, positioning, and remodeling in cultured human cells and medaka fish embryos using advanced cell biological technologies to understand the general principle and context-dependent regulations for chromosomal stability and cell fate control in vertebrate mitosis.
