Clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 enables us to generate targeted sequence changes in the genomes of cells and organisms. However, off-target effects have been a persistent problem hampering the development of therapeutics based on CRISPR/Cas9 and potentially confounding research results. Efforts to improve Cas9 specificity, like the development of RNA-guided FokI-nucleases (RFNs), usually come at the cost of editing efficiency and/or genome targetability. To overcome these limitations, we engineered improved chimeras of RFNs that enable higher cleavage efficiency and provide broader genome targetability, while retaining high fidelity for genome editing in human cells. Furthermore, we developed a new RFN ortholog derived from Staphylococcus aureus Cas9 and characterize its utility for efficient genome engineering. Finally, we demonstrate the feasibility of RFN orthologs to functionally hetero-dimerize to modify endogenous genes, unveiling a new dimension of RFN target design opportunities.
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http://dx.doi.org/10.1016/j.ymthe.2016.11.007 | DOI Listing |
J Exp Clin Cancer Res
May 2019
Department of Clinical Hematology, Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Chongqing Medical University, No.1, Yixueyuan Road, Chongqing, 400016, China.
Background: The bcr-abl fusion gene encodes BCR-ABL oncoprotein and plays a crucial role in the leukemogenesis of chronic myeloid leukemia (CML). Current therapeutic methods have limited treatment effect on CML patients with drug resistance or disease relapse. Therefore, novel therapeutic strategy for CML is essential to be explored and the CRISPR RNA-guided FokI nucleases (RFNs) meet the merits of variable target sites and specificity of cleavage enabled its suitability for gene editing of CML.
View Article and Find Full Text PDFMol Ther
February 2017
Stem Cell and Regenerative Biology, Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore 138672, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 119077, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore 639798, Singapore. Electronic address:
Clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 enables us to generate targeted sequence changes in the genomes of cells and organisms. However, off-target effects have been a persistent problem hampering the development of therapeutics based on CRISPR/Cas9 and potentially confounding research results. Efforts to improve Cas9 specificity, like the development of RNA-guided FokI-nucleases (RFNs), usually come at the cost of editing efficiency and/or genome targetability.
View Article and Find Full Text PDFSci Rep
October 2016
Dietmar-Hopp-Metabolic Center, Department of General Pediatrics, University Hospital, Heidelberg, Germany.
The CRISPR/Cas9 system is a recently developed genome editing technique. In this study, we used a modified CRISPR system, which employs the fusion of inactive Cas9 (dCas9) and the FokI endonuclease (FokI-dCas9) to correct the most common variant (allele frequency 21.4%) in the phenylalanine hydroxylase (PAH) gene - c.
View Article and Find Full Text PDFSci Rep
May 2016
Department of Biology, Miami University, Oxford, Ohio, 45056, USA.
The CRISPR system holds much promise for successful genome engineering, but therapeutic, industrial, and research applications will place high demand on improving the specificity and efficiency of this tool. CT-Finder (http://bioinfolab.miamioh.
View Article and Find Full Text PDFCurr Protoc Mol Biol
October 2015
Molecular Pathology Unit, Center for Computational and Integrative Biology and Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts.
The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system has been broadly adopted for highly efficient genome editing in a variety of model organisms and human cell types. Unlike previous genome editing technologies such as zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), CRISPR/Cas technology does not require complex protein engineering and can be utilized by any researcher proficient in basic molecular biology and cell culture techniques. This unit describes protocols for design and cloning of vectors expressing single or multiplex gRNAs, for transient transfection of human cell lines, and for quantitation of mutation frequencies by T7 endonuclease I assay.
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