Spatiotemporal dynamics of Spc105 regulates the assembly of the Drosophila kinetochore
Abstract
The formation of kinetochores shortly before each cell division is a prerequisite for proper chromosome segregation. The synchronous mitoses of Drosophila syncytial embryos have provided an ideal in vivo system to follow kinetochore assembly kinetics and so address the question of how kinetochore formation is regulated. We found that the nuclear exclusion of the Spc105/KNL1 protein during interphase prevents precocious assembly of the Mis12 complex. The nuclear import of Spc105 in early prophase and its immediate association with the Mis12 complex on centromeres are thus the first steps in kinetochore assembly. The cumulative kinetochore levels of Spc105 and Mis12 complex then determine the rate of Ndc80 complex recruitment commencing only after nuclear envelope breakdown. The carboxy-terminal part of Spc105 directs its nuclear import and is sufficient for the assembly of all core kinetochore components and CENP-C, when localized ectopically to centrosomes. Super-resolution microscopy shows that carboxy-terminus of Spc105 lies at the junction of the Mis12 and Ndc80 complexes on stretched kinetochores. Our study thus indicates that physical accessibility of kinetochore components plays a crucial role in the regulation of Drosophila kinetochore assembly and leads us to a model in which Spc105 is a licensing factor for its onset.
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BibTeX
@article{venkei2026spatiotemporal,
title = {{Spatiotemporal dynamics of Spc105 regulates the assembly of the Drosophila kinetochore}},
author = {Zsolt Venkei and Marcin Przewloka and Yaseen Ladak and Shahad Albadri and Alex Sossick and Gabor Juhasz and Béla Novák and David Glover},
journal = {Open Biology},
year = {2026},
month = oct,
doi = {10.1098/rsob.110032},
url = {https://hal.science/hal-05781574v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Spatiotemporal dynamics of Spc105 regulates the assembly of the Drosophila kinetochore
AU - Zsolt Venkei
AU - Marcin Przewloka
AU - Yaseen Ladak
AU - Shahad Albadri
AU - Alex Sossick
AU - Gabor Juhasz
AU - Béla Novák
AU - David Glover
PY - 2026
DA - 2026/10/06
JO - Open Biology
DO - 10.1098/rsob.110032
UR - https://hal.science/hal-05781574v1
AB - The formation of kinetochores shortly before each cell division is a prerequisite for proper chromosome segregation. The synchronous mitoses of Drosophila syncytial embryos have provided an ideal in vivo system to follow kinetochore assembly kinetics and so address the question of how kinetochore formation is regulated. We found that the nuclear exclusion of the Spc105/KNL1 protein during interphase prevents precocious assembly of the Mis12 complex. The nuclear import of Spc105 in early prophase and its immediate association with the Mis12 complex on centromeres are thus the first steps in kinetochore assembly. The cumulative kinetochore levels of Spc105 and Mis12 complex then determine the rate of Ndc80 complex recruitment commencing only after nuclear envelope breakdown. The carboxy-terminal part of Spc105 directs its nuclear import and is sufficient for the assembly of all core kinetochore components and CENP-C, when localized ectopically to centrosomes. Super-resolution microscopy shows that carboxy-terminus of Spc105 lies at the junction of the Mis12 and Ndc80 complexes on stretched kinetochores. Our study thus indicates that physical accessibility of kinetochore components plays a crucial role in the regulation of Drosophila kinetochore assembly and leads us to a model in which Spc105 is a licensing factor for its onset.
SN - 2046-2441
ER -