Midbody inheritance predicts re-entry into quiescence, but not lineage potential, in mouse hematopoietic stem cells.

Hematopoietic stem cells (HSCs) give rise to all blood cell lineages and possess long-term self-renewal potential. HSCs undergo symmetric division for their expansion and asymmetric division to generate one HSC and one progenitor cell that contribute to the production of mature blood cells. The midbody is a structure formed in the center of the intercellular bridge during cytokinesis. However, the midbody is either asymmetrically inherited by one daughter cell or symmetrically released after cell division, whether these distinct patterns of midbody inheritance influence HSC fate remain poorly understood. In this study, we designed a fusion protein humanized monomeric Kusabira-Orange 2 (hmKO2) and male germ cell Rac GTPase-activating protein (MgcRacGAP), which is a component of the midbody. We then traced the midbody inheritance during cell division and the future cell fates of HSC daughters after division by time-lapse imaging. As a result, we found that the midbody release correlated with the delay of the time to the next division but not with the lineage potential of HSCs, indicating the possibility that midbody remnant plays some roles in cell cycle progression.