着丝粒核小体结构研究进展

An Overview on Structure of Centromeric Nucleosomes

着丝粒是构成真核生物染色体的必需元件。在细胞有丝分裂或减数分裂时,微管通过动粒与染色体着丝粒连接,参与细胞分裂的染色体分离与分配过程,使染色体平均分配到子细胞中。构成着丝粒的基本单位是着丝粒特异的核小体,与常规核小体不同的是着丝粒核小体中的组蛋白H3被其变种——着丝粒组蛋白H3所替换。最近几年,着丝粒核小体的结构成为细胞生物学研究的热点之一。该文综述了最近在多种真核生物研究中,通过体外和体内实验,提出的着丝粒核小体结构的八聚体、六聚体、同型四聚体以及半八聚体模型,并对着丝粒核小体结构的动态模型与功能的关系进行了探讨。

As an essential element of eukaryotic chromosome, centromere is required for attachment to spindle microtubules and equally segregate the chromatin to two daughter cells during mitosis and meiosis. The fundamental unit of centromere is centromeric nucleosomes, which contains a histone H3 variant called centromere histone 3. In recent years, the structure of centromeric nucleosomes is becoming a hot topic for the cell biology researches. The models of octamers, hexamers, homotypic tetramers and hemisomes for centromeric nucleosome have been proposed recently from different eukaryotic organisms. This review described each centromere nucleosome model and provided potential mechanism based on in vivo and in vitro excrement. The relationship between the structure and function of the centromeric nucleosomes was also discussed.