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Centromere assembly requires selective recognition of centromeric chromatin by centromere protein N
Author(s) -
Straight Aaron,
Carroll Christopher
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.628.5
Subject(s) - centromere , kinetochore , chromatin , nucleosome , biology , histone h3 , microbiology and biotechnology , aurora b kinase , histone , genetics , chromosome , dna , gene
The kinetochore is a unique chromosomal locus that binds to the mitotic spindle so that chromosomes can segregate in mitosis. Kinetochore assembly requires the specialized chromatin of the centromere that is distinguished by the replacement of histone H3 with the histone H3‐variant centromere protein A (CENP‐A). CENP‐A is thought to epigenetically mark the centromere and is required for kinetochore assembly but it is not known how this epigenetic mark is recognized to initiate kinetochore assembly. We have explored the molecular basis for centromere recognition by developing a simple and rapid in vitro assay designed to identify human kinetochore components that directly and specifically interact with reconstituted CENP‐A nucleosomes. This approach led to discovery that centromere protein N (CENP‐N) is a DNA‐sequence independent CENP‐A‐nucleosome binding protein. Nucleosomes reconstituted with a chimeric histone H3 that contains only the centromere‐targeting domain of CENP‐A were sufficient for CENP‐N binding. Point mutations that disrupted binding of CENP‐N to CENP‐A nucleosomes in vitro blocked localization of CENP‐N to the centromere in vivo, indicating that nucleosome binding is required for the centromere‐specific localization of CENP‐N. Thus CENP‐N recognition of centromeric chromatin is an essential step in the initiation of centromere and kinetochore assembly.