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bioRxiv · 10.1101/2024.08.31.610619

The spatiotemporal distribution of LIN-5/NuMA regulates spindle orientation and tissue organization in the C. elegans germ line

Zellag, R. M.·Poupart, V.·Negishi, T.·Labbe, J.-C.·Gerhold, A. R.
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Abstract

Mitotic spindle orientation sets the cell division plane and is thus critical for maintaining tissue organization. The C. elegans gonad is tube-shaped, with germ cells forming a circumferential monolayer around a shared inner core of cytoplasm called the rachis. Each germ cell is connected to the rachis via a stable cytoplasmic bridge, polarizing germ cells along their rachis-basal axis. How this tissue organization is maintained during development is unclear, as germ cells lack the canonical cell-cell junctions that, in other tissue types, ensure proper spindle orientation. Here we use live-cell imaging of C. elegans germ cells, both in situ and in gonad explants, to show that the microtubule force generator dynein and its conserved regulator LIN-5/NuMA regulate spindle orientation in C. elegans germ cells and are required for germline tissue organization. We uncover a cyclic, polarized pattern of LIN-5/NuMA cortical localization that predicts centriole/centrosome positioning throughout the cell cycle, providing a means to align spindle orientation with the tissue plane. This work reveals a new mechanism by which oriented cell division can be achieved to maintain tissue organization during animal development.

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Zellag, R. M., Poupart, V., Negishi, T., Labbe, J.-C., Gerhold, A. R.. 2024-09-01. The spatiotemporal distribution of LIN-5/NuMA regulates spindle orientation and tissue organization in the C. elegans germ line. https://doi.org/10.1101/2024.08.31.610619

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