JMCB最新一期文章上线啦！

这期COLLECTION的主题为Innovative Methods and Techniques for Frontiers of Life Science

具体内容见：  https://academic.oup.com/jmcb/issue/7/4

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小编特别推荐下封面文章：

Efficient inversions and duplications of mammalian regulatory DNA elements and gene clusters by CRISPR/Cas9

Abstract

The human genome contains millions of DNAregulatoryelements and a large number of geneclusters, most of which have not been tested experimentally. The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) programed with a synthetic single-guide RNA (sgRNA) emerges as a method for genome editing in virtually any organisms. Here we report that targeted DNA fragment inversions and duplications could easily be achieved in human and mouse genomes by CRISPR with two sgRNAs. Specifically, we found that, in cultured human cells and mice, efficient precise inversions of DNA fragments ranging in size from a few tens of bp to hundreds of kb could be generated. In addition, DNA fragment duplications and deletions could also be generated by CRISPR through trans-allelic recombination between the Cas9-induced double-strand breaks (DSBs) on two homologous chromosomes (chromatids). Moreover, junctions of combinatorial inversions and duplications of the protocadherin (Pcdh) geneclusters induced by Cas9 with four sgRNAs could be detected. In mice, we obtained founders with alleles of precise inversions, duplications, and deletions of DNA fragments of variable sizes by CRISPR. Interestingly, we found that very efficientinversions were mediated by microhomology-mediated end joining (MMEJ) through short inverted repeats. We showed for the first time that DNA fragment inversions could be transmitted through germlines in mice. Finally, we applied this CRISPR method to a regulatory element of the Pcdhα cluster and found a new role in the regulation of members of the Pcdhγ cluster. This simple and efficient method should be useful in manipulating mammalian genomes to study millions of regulatoryDNAelements as well as vast numbers of geneclusters.

Keywords: DNA regulatory element inversion, duplication, deletion, CRISPR/Cas9, enhancer, genome manipulation, gene cluster

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-------------------------以下为作者对文章的简介（转载）-------------------

上海交通大学系统生物医学研究院吴强教授团队在Journal of Molecular Cell Biology杂志上发表了题为“EfficientInversions and Duplications of Mammalian Regulatory DNA Elements andGene Clusters by CRISPR/Cas9”的研究成果。  

CRISPR全称为成簇常间隔短回文重复，是源于细菌及古细菌中的一种免疫系统，它可以利用靶位点特异性的RNA指导Cas9蛋白对靶位点序列进行修饰。自2013年CRISPR/Cas9首次作为一种新一代基因编辑工具出现以来，科研工作者们开始利用这一系统在基因组中进行多种编辑。

吴强团队长期利用小鼠模式生物从事原钙粘蛋白基因表达调控及其在脑发育中功能研究，对原钙粘蛋白基因簇进行了一系列遗传学研究，在基因组编辑工具CRISPR技术飞速发展时，发现了CRISPR在DNA片段编辑中的新方法。该研究成果系统的阐述了如何利用CRISPR/Cas9系统对DNA片段进行高效地反转、复制和敲除，对于研究哺乳动物基因组中成千上万的DNA调控元件和很多基因簇非常有用，也将推动人类疾病转化医学研究。  

该研究得到国家自然科学基金的资助，由上海交通大学独立完成。该论文的共同第一作者为李金环和寿佳。