Ho Kung-Hsien, Tsuchiya Dai, Oliger Audrey C, Lacefield Soni
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Cell Rep. 2014 Dec 24;9(6):2027-33. doi: 10.1016/j.celrep.2014.11.037. Epub 2014 Dec 18.
In many eukaryotes, the centromere is epigenetically specified and not strictly defined by sequence. In contrast, budding yeast has a specific 125 bp sequence required for kinetochore function. Despite the difference in centromere specification, budding yeast and multicellular eukaryotic centromeres contain a highly conserved histone H3 variant, CENP-A. The localization of budding yeast CENP-A, Cse4, requires the centromere DNA binding components, which are not conserved in multicellular eukaryotes. Here, we report that Cse4 localizes and functions at a synthetic kinetochore assembly site that lacks centromere sequence. The outer kinetochore Dam1-DASH and inner kinetochore CBF3 complexes are required for Cse4 localization to that site. Furthermore, the natural kinetochore also requires the outer kinetochore proteins for full Cse4 localization. Our results suggest that Cse4 localization at a functional kinetochore does not require the recognition of a specific DNA sequence by the CBF3 complex; rather, its localization depends on stable interactions among kinetochore proteins.
在许多真核生物中,着丝粒是通过表观遗传确定的,并非由序列严格定义。相比之下,芽殖酵母具有一个动粒功能所需的特定125 bp序列。尽管着丝粒确定方式存在差异,但芽殖酵母和多细胞真核生物的着丝粒都含有一种高度保守的组蛋白H3变体CENP-A。芽殖酵母CENP-A(Cse4)的定位需要着丝粒DNA结合成分,而这些成分在多细胞真核生物中并不保守。在此,我们报告Cse4定位于一个缺乏着丝粒序列的合成动粒组装位点并在该位点发挥功能。外动粒Dam1-DASH复合体和内动粒CBF3复合体是Cse4定位于该位点所必需的。此外,天然动粒也需要外动粒蛋白来实现Cse4的完全定位。我们的结果表明,Cse4在功能性动粒上的定位并不需要CBF3复合体识别特定的DNA序列;相反,其定位取决于动粒蛋白之间的稳定相互作用。