In vitro centromere and kinetochore assembly on defined chromatin templates

Article

关键词: XENOPUS EGG EXTRACTS;    CENP-A NUCLEOSOMES;    AURORA B;    HISTONE;    COMPLEX;    PHOSPHORYLATION;    CHECKPOINT;    HJURP;    DNA;    ORGANIZATION;   

DOI  :  10.1038/nature10379

来源: SCIE

【 摘 要 】

During cell division, chromosomes are segregated to nascent daughter cells by attaching to the microtubules of the mitotic spindle through the kinetochore. Kinetochores are assembled on a specialized chromatin domain called the centromere, which is characterized by the replacement of nucleosomal histone H3 with the histone H3 variant centromere protein A(CENP-A). CENP-A is essential for centromere and kinetochore formation in all eukaryotes but it is unknown how CENP-A chromatin directs centromere and kinetochore assembly(1). Here we generate synthetic CENP-A chromatin that recapitulates essential steps of centromere and kinetochore assembly in vitro. We show that reconstituted CENP-A chromatin when added to cell-free extracts is sufficient for the assembly of centromere and kinetochore proteins, microtubule binding and stabilization, and mitotic checkpoint function. Using chromatin assembled from histone H3/CENP-A chimaeras, we demonstrate that the conserved carboxy terminus of CENP-A is necessary and sufficient for centromere and kinetochore protein recruitment and function but that the CENP-A targeting domain-required for new CENP-A histone assembly(2)-is not. These data show that two of the primary requirements for accurate chromosome segregation, the assembly of the kinetochore and the propagation of CENP-A chromatin, are specified by different elements in the CENP-A histone. Our unique cell-free system enables complete control and manipulation of the chromatin substrate and thus presents a powerful tool to study centromere and kinetochore assembly.

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