scholarly journals Optimization of multiplexed CRISPR/Cas9 system for highly efficient genome editing in Setaria viridis

2020 ◽  
Author(s):  
Trevor Weiss ◽  
Chunfang Wang ◽  
Xiaojun Kang ◽  
Hui Zhao ◽  
Maria Elena Gamo ◽  
...  
Keyword(s):  
Genome Editing ◽  
Transformation Method ◽  
Targeted Mutagenesis ◽  
Setaria Viridis ◽  
Photosynthetic Pathway ◽  
Repair Pathway ◽  
End Joining ◽  
Highly Efficient ◽  
Homozygous Mutations ◽  
High Throughput Manner

AbstractIn recent years, Setaria viridis has been developed as a model plant to better understand the C4 photosynthetic pathway in major crops. With the increasing availability of genomic resources for S. viridis research, highly efficient genome editing technologies are needed to create genetic variation resources for functional genomics. Here, we developed a protoplast assay to rapidly optimize the multiplexed CRISPR/Cas9 system in S. viridis. Targeted mutagenesis efficiency was further improved by an average of 1.4-fold with the exonuclease, Trex2. Distinctive mutation profiles were found in the Cas9_Trex2 samples with 94% of deletions larger than 10bp, and less than 1% of mutations being insertions. Further analyses indicated that 52.2% of deletions induced by Cas9_Trex2, as opposed to 3.5% by Cas9 alone, were repaired through microhomology-mediated end joining (MMEJ) rather than the canonical NHEJ DNA repair pathway. Combined with the robust agrobacterium-mediated transformation method with more than 90% efficiency, the multiplex CRISPR/Cas9_Trex2 system was demonstrated to induce targeted mutations in two tightly linked genes, svDrm1a and svDrm1b, at the frequency ranging from 73% to 100% in T0 plants. These mutations were transmitted to at least 60% of the transgene-free T1 plants with 33% of them containing bi-allelic or homozygous mutations in both genes. This highly efficient multiplex CRISPR/Cas9_Trex2 system makes it possible to create a large mutant resource for S. viridis in a rapid and high throughput manner, and has the potential to be widely applicable in achieving more predictable MMEJ-mediated mutations in many plant species.

scholarly journals Efficient genome editing and gene knockout in Setaria viridis with CRISPR/Cas9 directed gene editing by the non-homologous end-joining pathway

2021 ◽  
Author(s):  
Marcos Fernando Basso ◽  
Karoline Estefani Duarte ◽  
Thais Ribeiro Santiago ◽  
Wagner Rodrigo de Souza ◽  
Bruno de Oliveira Garcia ◽  
...  
Keyword(s):  
Genome Editing ◽  
Gene Editing ◽  
Gene Knockout ◽  
Setaria Viridis ◽  
End Joining ◽  
Non Homologous End Joining

scholarly journals A CRISPR-Assisted Nonhomologous End-Joining Strategy for Efficient Genome Editing in Mycobacterium tuberculosis

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Mei-Yi Yan ◽  
Si-Shang Li ◽  
Xin-Yuan Ding ◽  
Xiao-Peng Guo ◽  
Qi Jin ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Genome Editing ◽  
Large Scale ◽  
Nonhomologous End Joining ◽  
Genetic Mutations ◽  
Repair Pathway ◽  
End Joining ◽  
Content Type ◽  
Nhej Repair ◽  
Short Palindromic Repeat

ABSTRACT New tools for genetic manipulation of Mycobacterium tuberculosis are needed for the development of new drug regimens and vaccines aimed at curing tuberculosis infections. Clustered regularly interspaced short palindromic repeat (CRISPR)–CRISPR-associated protein (Cas) systems generate a highly specific double-strand break at the target site that can be repaired via nonhomologous end joining (NHEJ), resulting in the desired genome alteration. In this study, we first improved the NHEJ repair pathway and developed a CRISPR-Cas-mediated genome-editing method that allowed us to generate markerless deletion in Mycobacterium smegmatis, Mycobacterium marinum, and M. tuberculosis. Then, we demonstrated that this system could efficiently achieve simultaneous generation of double mutations and large-scale genetic mutations in M. tuberculosis. Finally, we showed that the strategy we developed can also be used to facilitate genome editing in Escherichia coli. IMPORTANCE The global health impact of M. tuberculosis necessitates the development of new genetic tools for its manipulation, to facilitate the identification and characterization of novel drug targets and vaccine candidates. Clustered regularly interspaced short palindromic repeat (CRISPR)–CRISPR-associated protein (Cas) genome editing has proven to be a powerful genetic tool in various organisms; to date, however, attempts to use this approach in M. tuberculosis have failed. Here, we describe a genome-editing tool based on CRISPR cleavage and the nonhomologous end-joining (NHEJ) repair pathway that can efficiently generate deletion mutants in M. tuberculosis. More importantly, this system can generate simultaneous double mutations and large-scale genetic mutations in this species. We anticipate that this CRISPR-NHEJ-assisted genome-editing system will be broadly useful for research on mycobacteria, vaccine development, and drug target profiling.

Impact of chromatin context on Cas9-induced DNA double-strand break repair pathway balance

2020 ◽  
Author(s):  
Ruben Schep ◽  
Eva K. Brinkman ◽  
Christ Leemans ◽  
Xabier Vergara ◽  
Ben Morris ◽  
...  
Keyword(s):  
Genome Editing ◽  
Strand Break ◽  
Double Strand Break ◽  
Repair Pathway ◽  
End Joining ◽  
Dsb Repair ◽  
Dna Double Strand Break ◽  
Repair Pathways ◽  
Non Homologous End Joining ◽  
The Impact

AbstractDNA double-strand break (DSB) repair is mediated by multiple pathways, including classical non-homologous end-joining pathway (NHEJ) and several homology-driven repair pathways. This is particularly important for Cas9-mediated genome editing, where the outcome critically depends on the pathway that repairs the break. It is thought that the local chromatin context affects the pathway choice, but the underlying principles are poorly understood. Using a newly developed multiplexed reporter assay in combination with Cas9 cutting, we systematically measured the relative activities of three DSB repair pathways as function of chromatin context in >1,000 genomic locations. This revealed that NHEJ is broadly biased towards euchromatin, while microhomology-mediated end-joining (MMEJ) is more efficient in specific heterochromatin contexts. In H3K27me3-marked heterochromatin, inhibition of the H3K27 methyltransferase EZH2 shifts the balance towards NHEJ. Single-strand templated repair (SSTR), often used for precise CRISPR editing, competes with MMEJ, and this competition is weakly associated with chromatin context. These results provide insight into the impact of chromatin on DSB repair pathway balance, and guidance for the design of Cas9-mediated genome editing experiments.

scholarly journals Application of genome editing tools in plants

2021 ◽  
Vol 19 (1) ◽  
pp. 15-40
Author(s):  
Nguyen Duc Thanh
Keyword(s):  
Genome Editing ◽  
Target Gene ◽  
Crop Improvement ◽  
Double Sequence ◽  
Targeted Mutagenesis ◽  
Nonhomologous End Joining ◽  
Transcription Activator ◽  
End Joining ◽  
Base Editing ◽  
Living Organisms

Genome editing technology is the genome modification techniques, such as targeted mutagenesis or insert/delete/replacement at specific locations in the genome of living organisms. Genome editing is based on the creation of double sequence break (DSB) in a specific location and DNA repair via nonhomologous end joining (NHEJ) or homology direct repair (HDR). The development of sequence-specific nuclease (SSN) allows precise editing of the target gene. These SSNs include: meganuclease (MN), zinc finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN) and CRISPR-associated nuclease (Cas) including CRISPR/Cas9 (from Streptococcus pyogenes) and CRISPR/Cpf1 (from Prevoltella and Francisella1). These are the genome editing tools used to create DSBs at specific locations of the genome. Recently, the base editing (BE) and prime editing (PE) tools have been reported. This review will cover the basics of these tools and their application in genome editing in plants, especially providing the most up-to-date information on their application in crop improvement.

scholarly journals Optimization of multiplexed CRISPR/Cas9 system for highly efficient genome editing in Setaria viridis

2020 ◽  
Vol 104 (3) ◽  
pp. 828-838 ◽  
Author(s):  
Trevor Weiss ◽  
Chunfang Wang ◽  
Xiaojun Kang ◽  
Hui Zhao ◽  
Maria Elena Gamo ◽  
...  
Keyword(s):  
Genome Editing ◽  
Setaria Viridis ◽  
Highly Efficient

scholarly journals CRISPResso: sequencing analysis toolbox for CRISPR genome editing

2015 ◽  
Author(s):  
Luca Pinello ◽  
Matthew C Canver ◽  
Megan D Hoban ◽  
Stuart H Orkin ◽  
Donald B Kohn ◽  
...  
Keyword(s):  
Genome Editing ◽  
Comprehensive Evaluation ◽  
Targeted Mutagenesis ◽  
Sequencing Analysis ◽  
End Joining ◽  
Sequencing Errors ◽  
Homology Directed Repair ◽  
Experimental Variation ◽  
Non Homologous End Joining ◽  
Sequence Quality

Recent progress in genome editing technologies, in particular the CRISPR-Cas9 system, has provided new opportunities to investigate the biological functions of genomic sequences by targeted mutagenesis. Double strand breaks (DSBs) resulting from site-specific Cas9 cleavage can be resolved by endogenous DNA repair pathways such as non-homologous end joining (NHEJ) or homology-directed repair (HDR). Deep sequencing of amplified genomic regions allows for quantitative and sensitive detection of targeted mutations. However, no standard analytic tool to date has been developed to systematically enumerate and visualize these events, and to solve challenging issues such as amplification or sequencing errors, experimental variation in sequence quality, ambiguous alignment of variable length indels, and difficulty in deconvoluting mixed HDR/NHEJ outcomes. To address these issues we developed CRISPResso, a robust computational pipeline that enables accurate quantification and visualization of CRISPR-Cas9 outcomes as well as comprehensive evaluation of effects on coding sequences, noncoding elements and selected off-target sites.

scholarly journals The Gene Sculpt Suite: a set of tools for genome editing

2019 ◽  
Vol 47 (W1) ◽  
pp. W175-W182 ◽  
Author(s):  
Carla M Mann ◽  
Gabriel Martínez-Gálvez ◽  
Jordan M Welker ◽  
Wesley A Wierson ◽  
Hirotaka Ata ◽  
...  
Keyword(s):  
Genome Editing ◽  
Zinc Finger Nucleases ◽  
Machine Learning Method ◽  
Repair Pathway ◽  
End Joining ◽  
Web Based ◽  
Double Stranded Dna ◽  
Break Site ◽  
Dna Editing ◽  
Genomic Locations

Abstract The discovery and development of DNA-editing nucleases (Zinc Finger Nucleases, TALENs, CRISPR/Cas systems) has given scientists the ability to precisely engineer or edit genomes as never before. Several different platforms, protocols and vectors for precision genome editing are now available, leading to the development of supporting web-based software. Here we present the Gene Sculpt Suite (GSS), which comprises three tools: (i) GTagHD, which automatically designs and generates oligonucleotides for use with the GeneWeld knock-in protocol; (ii) MEDJED, a machine learning method, which predicts the extent to which a double-stranded DNA break site will utilize the microhomology-mediated repair pathway; and (iii) MENTHU, a tool for identifying genomic locations likely to give rise to a single predominant microhomology-mediated end joining allele (PreMA) repair outcome. All tools in the GSS are freely available for download under the GPL v3.0 license and can be run locally on Windows, Mac and Linux systems capable of running R and/or Docker. The GSS is also freely available online at www.genesculpt.org.

scholarly journals Withanolide D Enhances Radiosensitivity of Human Cancer Cells by Inhibiting DNA Damage Non-homologous End Joining Repair Pathway

2020 ◽  
Vol 9 ◽  
Author(s):  
Jerome Lacombe ◽  
Titouan Cretignier ◽  
Laetitia Meli ◽  
E. M. Kithsiri Wijeratne ◽  
Jean-Luc Veuthey ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Human Cancer ◽  
Repair Pathway ◽  
End Joining ◽  
Human Cancer Cells ◽  
Non Homologous End Joining

scholarly journals Knock-in and precise nucleotide substitution using near-PAMless engineered Cas9 variants in Dictyostelium discoideum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuu Asano ◽  
Kensuke Yamashita ◽  
Aoi Hasegawa ◽  
Takanori Ogasawara ◽  
Hoshie Iriki ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dictyostelium Discoideum ◽  
Streptococcus Pyogenes ◽  
Nucleotide Substitution ◽  
Point Mutations ◽  
Targeted Mutagenesis ◽  
Single Amino Acid ◽  
Specific Gene ◽  
Knock Out ◽  
Protospacer Adjacent Motif

AbstractThe powerful genome editing tool Streptococcus pyogenes Cas9 (SpCas9) requires the trinucleotide NGG as a protospacer adjacent motif (PAM). The PAM requirement is limitation for precise genome editing such as single amino-acid substitutions and knock-ins at specific genomic loci since it occurs in narrow editing window. Recently, SpCas9 variants (i.e., xCas9 3.7, SpCas9-NG, and SpRY) were developed that recognise the NG dinucleotide or almost any other PAM sequences in human cell lines. In this study, we evaluated these variants in Dictyostelium discoideum. In the context of targeted mutagenesis at an NG PAM site, we found that SpCas9-NG and SpRY were more efficient than xCas9 3.7. In the context of NA, NT, NG, and NC PAM sites, the editing efficiency of SpRY was approximately 60% at NR (R = A and G) but less than 22% at NY (Y = T and C). We successfully used SpRY to generate knock-ins at specific gene loci using donor DNA flanked by 60 bp homology arms. In addition, we achieved point mutations with efficiencies as high as 97.7%. This work provides tools that will significantly expand the gene loci that can be targeted for knock-out, knock-in, and precise point mutation in D. discoideum.

scholarly journals First genome edited poinsettias: targeted mutagenesis of flavonoid 3′-hydroxylase using CRISPR/Cas9 results in a colour shift

2021 ◽  
Author(s):  
Daria Nitarska ◽  
Robert Boehm ◽  
Thomas Debener ◽  
Rares Calin Lucaciu ◽  
Heidi Halbwirth
Keyword(s):  
Transgenic Plants ◽  
Genome Editing ◽  
Ornamental Plants ◽  
Targeted Mutagenesis ◽  
Cloning And Expression ◽  
Euphorbia Pulcherrima ◽  
Loss Of Function ◽  
Wild Type ◽  
Promising Tool ◽  
Reddish Orange

AbstractThe CRISPR/Cas9 system is a remarkably promising tool for targeted gene mutagenesis, and becoming ever more popular for modification of ornamental plants. In this study we performed the knockout of flavonoid 3′-hydroxylase (F3′H) with application of CRISPR/Cas9 in the red flowering poinsettia (Euphorbia pulcherrima) cultivar ‘Christmas Eve’, in order to obtain plants with orange bract colour, which accumulate prevalently pelargonidin. F3′H is an enzyme that is necessary for formation of cyanidin type anthocyanins, which are responsible for the red colour of poinsettia bracts. Even though F3′H was not completely inactivated, the bract colour of transgenic plants changed from vivid red (RHS 45B) to vivid reddish orange (RHS 33A), and cyanidin levels decreased significantly compared with the wild type. In the genetically modified plants, an increased ratio of pelargonidin to cyanidin was observed. By cloning and expression of mutated proteins, the lack of F3′H activity was confirmed. This confirms that a loss of function mutation in the poinsettia F3′H gene is sufficient for obtaining poinsettia with orange bract colour. This is the first report of successful use of CRISPR/Cas9 for genome editing in poinsettia.

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