NudE regulates dynein at kinetochores but is dispensable for other dynein functions in the C. elegans early embryo

In mitosis, themolecular motor dynein is recruited to kinetochores by the Rod-Zw10-Zwilch complex (RZZ) and Spindly to control spindle assembly checkpoint (SAC) signaling and microtubule attachment. How the ubiquitous dynein co-factors Lis1 and NudE contribute to these functions remains poorly understood. Here, we show that the C. elegans NudE homolog NUD-2 is dispensable for dynein- and LIS-1-dependent mitotic spindle assembly in the zygote. This facilitates functional characterization of kinetochore-localized NUD-2, which is recruited by the CENP-F-like proteins HCP-1 and HCP-2 independently of RZZ- Spindly and dynein-LIS-1. Kinetochore dynein levels are reduced in ¿nud-2 embryos, and, as occurs upon RZZ inhibition, loss of NUD-2 delays the formation of load-bearing kinetochore-microtubule attachments and causes chromatin bridges in anaphase. Survival of ¿nud-2 embryos requires a functional SAC, and kinetochores without NUD-2 recruit an excess of SAC proteins. Consistent with this, SAC signaling in early ¿nud-2 embryos extends mitotic duration and prevents high rates of chromosome mis-segregation. Our results reveal that both NUD-2 and RZZ-Spindly are essential for dynein function at kinetochores, and that the gain in SAC strength during early embryonic development is relevant under conditions that mildly perturb mitosis.This project was funded by the European Research Council under the European Union’s Seventh Framework Programme (ERC grant agreement no. ERC-2013-StG-338410-DYNEINOME to R.G.), and the European Union’s Horizon 2020 Research and Innovation Programme (ERC grant agreement no. ERC-2014-StG-640553-ACTOMYO to A.X.C.). Additional funding was fromthe European Molecular Biology Organization (Installation Grant; R.G.), from the Fundação para a Ciência e a Tecnologia(IF/01015/2013/CP1157/CT0006; R.G.), and from the project ‘Norte-01-0145-FEDER-000029, Advancing cancer research: from basic knowledge to application’, supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (FEDER). Deposited in PMC for immediate release