Celsr1 and CAMSAP3 differently regulate intercellular and intracellular cilia orientation in oviduct multiciliated cells
The molecular mechanisms by which cilia orientation is coordinated within and between multiciliated cells (MCCs) is not fully understood. By observing the orientation of basal bodies (BB) in MCCs of mouse oviducts, here, we show that Celsr1, a planar cell polarity (PCP) factor involved in tissue polarity regulation, is dispensable for determining BB orientation in individual cells, whereas CAMSAP3, a microtubule minus-end regulator, is critical for this process but not for PCP. MCCs exhibit a characteristic BB orientation and microtubule gradient along the tissue axis, and these intracellular polarities were maintained in the cells lacking Celsr1, although the intercellular coordination of the polarities was partly disrupted. On the other hand, CAMSAP3 regulated the assembly of microtubules interconnecting BBs by localizing at the BBs, and its mutation led to disruption of intracellular coordination of BB orientation, but not affecting PCP factor localization. Thus, both Celsr1 and CAMSAP3 are responsible for BB orientation but in distinct ways; and therefore, their cooperation should be critical for generating functional multiciliated tissues.