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Mol Biol Cell. 2008 Feb;19(2):587-94. Epub 2007 Nov 28.

KNL1 and the CENP-H/I/K complex coordinately direct kinetochore assembly in vertebrates.

Author information

1
Ludwig Institute for Cancer Research, and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA. icheese@wi.mit.edu

Abstract

Chromosome segregation during mitosis requires the assembly of a large proteinaceous structure termed the kinetochore. In Caenorhabditis elegans, KNL-1 is required to target multiple outer kinetochore proteins. Here, we demonstrate that the vertebrate KNL1 counterpart is essential for chromosome segregation and is required to localize a subset of outer kinetochore proteins. However, unlike in C. elegans, depletion of vertebrate KNL1 does not abolish kinetochore localization of the microtubule-binding Ndc80 complex. Instead, we show that KNL1 and CENP-K, a subunit of a constitutively centromere-associated complex that is missing from C. elegans, coordinately direct Ndc80 complex localization. Simultaneously reducing both hKNL1 and CENP-K function abolishes all aspects of kinetochore assembly downstream of centromeric chromatin and causes catastrophic chromosome segregation defects. These findings explain discrepancies in kinetochore assembly pathways between different organisms and reveal a surprising plasticity in the assembly mechanism of an essential cell division organelle.

PMID:
18045986
PMCID:
PMC2230600
DOI:
10.1091/mbc.e07-10-1051
[Indexed for MEDLINE]
Free PMC Article

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