《生命科学》 2016, 28(4): 420-426
摘 要：摘 要：人类基因组测序成功后，人们翻开了隐藏自身秘密的蓝图，而如何正确地解读和利用该蓝图成为全球科学家关注的焦点。基因编辑技术的飞跃式发展为基因组功能研究提供了关键性工具。目前常用的基因编辑技术包括ZFN (zinc finger nuclease)、TALEN (transcription activator-like effector nuclease) 和CRISPR/Cas9 (clustered regularly interspaced short palindromic repeat/CRISPR-associated 9) 这三种系统，而CRISPR/Cas9 系统以其简单、高效和低成本等特点，在极短的时间内被广泛地应用于从细菌到人等各个物种中，为深入认识基因功能和治疗遗传性疾病带来了曙光。目前，人们已经利用CRISPR/Cas9 系统成功地在动物受精卵中进行基因编辑，从而揭示动物胚胎发育的调控机制。此外，通过在受精卵中对遗传疾病的突变位点进行编辑，人们已经获得基因校正的正常的动物。大量的研究结果显示，人类的胚胎发育机制有别于模式动物；此外，还有上千种单基因突变导致的遗传疾病在成年后无法进行有效的治疗。为了探讨CRISPR/Cas9 系统是否能应用于人类早期胚胎发育调控机制的研究及遗传性疾病突变的有效修复，通过尝试利用生
殖临床中自然产生的、因无法正常发育而被废弃的三原核受精卵作为模型，研究了CRISPR/ Cas9系统在人类早期胚胎中对中国南方常见的地中海贫血突变位点的编辑效率以及存在的技术风险。研究结果显示CRISPR/Cas9 系统可以在人三原核受精卵中编辑突变位点，但目前的技术还存在脱靶效应、胚胎镶嵌性和同源重组效率低等问题。该研究工作推动了国际人类基因编辑峰会的召开，最终，科学界达成的共识认为在人类体细胞、胚胎及生殖细胞中进行基因编辑技术的基础研究是极其重要的。针对这一全球关注的重大科学研究事件进行回顾与展望。
Abstract: Abstract: The success of human genome sequencing uncovered the blueprint of our lives. However， how to annotate and utilize this genomic information becomes a central issue for the scientists all over the world. Thanks to the rapid development of gene editing technology， including zinc finger nuclease (ZFN)， transcription activator-like effector nuclease (TALEN)， and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPRassociated 9 (Cas9) system， the functional study on human genome has made great progress in recent years. Among them， CRISPR/Cas9 system is the most widely used genome editing tool that has been applied in a variety of species for ever since its debut， due to its simplicity， high efficiency and low cost. These advantages enable CRISPR/Cas9 system to be the most promising technology that helps to understand gene function thoroughly and wipe out genetic disease completely. Scientists have already tried to use CRISPR/Cas9 for studying the regulation mechanism of embryo development by genome editing， such as successfully correcting disease mutations in animal zygotes. However， human embryo development， as revealed by extensive studies， is quite different from animal models. In addition， thousands of human genetic diseases caused by single gene mutation cannot be cured at present. Therefore， we aim to explore the feasibility of studying human early embryo development and correcting disease mutations via CRISPR/Cas9-mediated gene editing in human zygotes. To achieve this aim， we chose nonviable tripronuclear zygotes as the research model and tried to study the editing efficiency and technical risks of correcting β-thalassemia disease mutation， which is widely distributed among people in South China area. Our results showed that CRISPR/Cas9 can edit mutant gene efficiently in human tripronuclear zygotes. However，notable off-target cleavages of Cas9 have also been observed. In addition， we found that gene-edited embryos are mosaic and the efficiency of homology-directed repair is low. Our work promoted the convening of international summit on Human Gene-Editing. During the meeting， scientists around the world reached a consensus that basic research on gene editing is extremely important for editing genetic sequences in human somatic cells， embryos and germ cells. Herein， we reviewed this worldwide-concerned science event.
