Department of Biochemistry and Molecular Biology, The George Washington University Medical School, Washington, D. C. 20037, USA.
J Biol Chem. 2013 Jan 18;288(3):1480-8. doi: 10.1074/jbc.M112.429266. Epub 2012 Nov 26.
The centromere is an epigenetically designated chromatin domain that is essential for the accurate segregation of chromosomes during mitosis. The incorporation of centromere protein A (CENP-A) into chromatin is fundamental in defining the centromeric loci. Newly synthesized CENP-A is loaded at centromeres in early G(1) phase by the CENP-A-specific histone chaperone Holliday junction recognition protein (HJURP) coupled with other chromatin assembly factors. However, it is unknown whether there are additional HJURP-interacting factor(s) involving in this process. Here we identify acidic nucleoplasmic DNA-binding protein 1 (And-1) as a new factor that is required for the assembly of CENP-A nucleosomes. And-1 interacts with both CENP-A and HJURP in a prenucleosomal complex, and the association of And-1 with CENP-A is increased during the cell cycle transition from mitosis to G(1) phase. And-1 down-regulation significantly compromises chromosome congression and the deposition of HJURP-CENP-A complexes at centromeres. Consistently, overexpression of And-1 enhances the assembly of CENP-A at centromeres. We conclude that And-1 is an important factor that functions together with HJURP to facilitate the cell cycle-specific recruitment of CENP-A to centromeres.
着丝粒是一种表观遗传指定的染色质结构域,对于有丝分裂过程中染色体的准确分离至关重要。着丝粒蛋白 A (CENP-A) 掺入染色质对于定义着丝粒区域是基本的。新合成的 CENP-A 通过 CENP-A 特异性组蛋白伴侣 Holliday 结识别蛋白 (HJURP) 与其他染色质组装因子在 G1 早期加载到着丝粒上。然而,目前尚不清楚是否存在其他与 HJURP 相互作用的因子(s)参与这个过程。在这里,我们鉴定酸性核质 DNA 结合蛋白 1 (And-1) 为参与 CENP-A 核小体组装的新因子。And-1 在核小体前复合物中与 CENP-A 和 HJURP 相互作用,并且在细胞周期从有丝分裂到 G1 期的过渡过程中,And-1 与 CENP-A 的结合增加。And-1 的下调显著损害了染色体的聚集和 HJURP-CENP-A 复合物在着丝粒上的沉积。一致地,过量表达 And-1 增强了 CENP-A 在着丝粒上的组装。我们得出结论,And-1 是一个重要的因子,与 HJURP 一起共同促进 CENP-A 在细胞周期特异性招募到着丝粒。