美国宾夕法尼亚州大学Ben E. Black研究组宣布他们开发了一种绕过着丝粒DNA成功合成人工染色体的方法。2019年7月25日出版的《细胞》发表了这项成果。

研究团队开发了一种新的不同于以往被限制了的HAC类型。该方法依靠初始CENP-A核小体播种策略， 缺乏重复着丝粒DNA结构形成了多个足够的HAC（没有出现基因组DNA的摄取）。相比传统α-卫星 HAC的形成，非重复性的构造可以形成功能性的HACs，无需CENP-B或初始CENP-A核小体播种。该研究揭示了不同DNA序列类型形成着丝粒的不同路径，简化了HACs的构建及表征，使得合成哺乳动物基因组变得更加便利。

据介绍，最近在合成出芽酵母染色体方面的突破，推动了合成哺乳动物染色体和基因组的创建。与芽殖酵母不同，哺乳动物需要依赖组蛋白H3异体，CENP-A蛋白，从而后天地特异性确定着丝粒位置（染色体分离的关键位置）。以前的人类人工染色体（HACs）需要大量的着丝粒α-卫星重复序列，其中包含DNA序列特异性结合蛋白（CENP-B）的结合位点。

附：英文原文

Title: Human Artificial Chromosomes that Bypass Centromeric DNA

Author: Glennis A. Logsdon, Craig W. Gambogi, Mikhail A. Liskovykh, Karen H. Miga, Patrick Heun, Ben E. Black

Issue&Volume: Volume 178 Issue 3

Abstract: Recent breakthroughs with synthetic budding yeast chromosomes expedite the creation of synthetic mammalian chromosomes and genomes. Mammals, unlike budding yeast, depend on the histone H3 variant, CENP-A, to epigenetically specify the location of the centromere—the locus essential for chromosome segregation. Prior human artificial chromosomes (HACs) required large arrays of centromeric α-satellite repeats harboring binding sites for the DNA sequence-specific binding protein, CENP-B. We report the development of a type of HAC that functions independently of these constraints. Formed by an initial CENP-A nucleosome seeding strategy, a construct lacking repetitive centromeric DNA formed several self-sufficient HACs that showed no uptake of genomic DNA. In contrast to traditional α-satellite HAC formation, the non-repetitive construct can form functional HACs without CENP-B or initial CENP-A nucleosome seeding, revealing distinct paths to centromere formation for different DNA sequence types. Our developments streamline the construction and characterization of HACs to facilitate mammalian synthetic genome efforts.

DOI: https://doi.org/10.1016/j.cell.2019.06.006

Source: https://www.cell.com/cell/fulltext/S0092-8674(19)30634-8#