多组学之表观组—CENH3变体

图1 动粒组装CENH3是H3组蛋白的一种变体是着丝粒的定位标记是着丝粒功能和动粒组装的必要成分图1[1]。在酵母中研究发现CENH3的突变会导致染色体分离失常和致死[2]。着丝粒能保证染色体在有丝分裂过程中发生正确的分离。研究证明DNA序列不足以保证着丝粒的位置说明着丝粒的位置主要由表观因素决定[3]。以前认为着丝粒区域应当包含串联重复序列或者转座子序列但是经过研究发现这些序列特征对着丝粒定位不是必要的[4]。CENH3的进化特征是N端序列歧化非常厉害图2只有非常近的近源物种才会相似度高而C端保守性强[5]。CENH3有一个重要的应用CENH3的突变能诱导单倍体的形成[6]。研究发现CENA-P的错误定位会导致发育延迟[7]。图2 CENH3的N端歧化现象参考文献1、Allshire R. C., Karpen G. H., Epigenetic regulation of centromeric chromatin: old dogs, new tricks? Nat. Rev. Genet. 9, 923 (2008).2、 Stoler, S., Keith, K. C., Curnick, K. E., and Fitzgerald-Hayes, M. (1995). A mutation in CSE4, an essential gene encoding a novel chromatin-associated protein in yeast, causes chromosome nondisjunction and cell cycle arrest at mitosis. Genes Dev. 9, 573–586. doi: 10.1101/gad.9.5.5733、 Allshire R. C., Karpen G. H., Epigenetic regulation of centromeric chromatin: old dogs, new tricks? Nat. Rev. Genet. 9, 923 (2008).4、 Marshall, O. J., Chueh, A. C., Wong, L. H., and Choo, K. A. (2008). Neocentromeres: new insights into centromere structure, disease development, and karyotype evolution. Am. J. Hum. Genet. 82, 261–282. doi: 10.1016/j.ajhg.2007.11.0095、 Malik, H. S., and Henikoff, S. (2003). Phylogenomics of the nucleosome. Nat. Struct. Mol. Biol. 10, 882–891. doi: 10.1038/nsb9966、 Ravi, M., and Chan, S. W. L. (2010). Haploid plants produced by centromeremediated genome elimination. Nature 464, 615–618. doi: 10.1038/nature088427、L.E. Voullaire, H.R. Slater, V. Petrovic, K.H. Choo, A functional marker centromere with no detectable alpha-satellite, satellite III, or CENP-B protein: activation of a latent centromere? Am. J. Hum. Genet. 52 (1993) 1153–1163.