scholarly journals Efficient CRISPR/Cas12a-based genome editing toolbox for metabolic engineering in Methanococcus maripaludis

2021 ◽  
Author(s):  
Jichen Bao ◽  
Silvan Scheller
Keyword(s):  
Metabolic Engineering ◽  
Genome Editing ◽  
Value Added ◽  
Primary Metabolism ◽  
Methanococcus Maripaludis ◽  
Knock Out ◽  
Homology Directed Repair ◽  
A Genome ◽  
Product Scope ◽  
Positive Rate

Methanococcus maripaludis is a fast-growing and genetically tractable methanogen. To become a useful host organism for the biotechnological conversion of CO2 and renewable hydrogen to fuels and value-added products, its product scope needs to be extended. Metabolic engineering requires reliable and efficient genetic tools, in particular for genome editing related to the primary metabolism that may affect cell growth. We have constructed a genome editing toolbox by utilizing Cas12a from Lachnospiraceae bacterium ND2006 (LbCas12a) in combination with the homology-directed repair machinery natively present in M. maripaludis. The toolbox enables gene knock-out with a positive rate typically above 89%, despite M. maripaludis being hyper-polyploid. We have replaced the flagellum operon (around 8.9kb) by a beta-glucuronidase gene to demonstrate a larger deletion, and to enable quantification of promotor strengths. The CRISPR/LbCas12a toolbox presented here is currently perhaps the most reliable and fastest method for genome editing in a methanogen.

scholarly journals Efficient Cas9-based genome editing of Rhodobacter sphaeroides for metabolic engineering

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Ioannis Mougiakos ◽  
Enrico Orsi ◽  
Mohammad Rifqi Ghiffary ◽  
Wilbert Post ◽  
Alberto de Maria ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Homologous Recombination ◽  
Genome Editing ◽  
Rhodobacter Sphaeroides ◽  
Genome Engineering ◽  
Start Codon ◽  
Terpene Biosynthesis ◽  
Knock Out ◽  
A Genome ◽  
Coa Reductase

Abstract Background Rhodobacter sphaeroides is a metabolically versatile bacterium that serves as a model for analysis of photosynthesis, hydrogen production and terpene biosynthesis. The elimination of by-products formation, such as poly-β-hydroxybutyrate (PHB), has been an important metabolic engineering target for R. sphaeroides. However, the lack of efficient markerless genome editing tools for R. sphaeroides is a bottleneck for fundamental studies and biotechnological exploitation. The Cas9 RNA-guided DNA-endonuclease from the type II CRISPR-Cas system of Streptococcus pyogenes (SpCas9) has been extensively employed for the development of genome engineering tools for prokaryotes and eukaryotes, but not for R. sphaeroides. Results Here we describe the development of a highly efficient SpCas9-based genomic DNA targeting system for R. sphaeroides, which we combine with plasmid-borne homologous recombination (HR) templates developing a Cas9-based markerless and time-effective genome editing tool. We further employ the tool for knocking-out the uracil phosphoribosyltransferase (upp) gene from the genome of R. sphaeroides, as well as knocking it back in while altering its start codon. These proof-of-principle processes resulted in editing efficiencies of up to 100% for the knock-out yet less than 15% for the knock-in. We subsequently employed the developed genome editing tool for the consecutive deletion of the two predicted acetoacetyl-CoA reductase genes phaB and phbB in the genome of R. sphaeroides. The culturing of the constructed knock-out strains under PHB producing conditions showed that PHB biosynthesis is supported only by PhaB, while the growth of the R. sphaeroides ΔphbB strains under the same conditions is only slightly affected. Conclusions In this study, we combine the SpCas9 targeting activity with the native homologous recombination (HR) mechanism of R. sphaeroides for the development of a genome editing tool. We further employ the developed tool for the elucidation of the PHB production pathway of R. sphaeroides. We anticipate that the presented work will accelerate molecular research with R. sphaeroides.

scholarly journals Programmed genome editing of the omega-1 ribonuclease 1 of the blood fluke,Schistosoma mansoni

2018 ◽  
Author(s):  
Wannaporn Ittiprasert ◽  
Victoria H. Mann ◽  
Shannon E. Karinshak ◽  
Avril Coghlan ◽  
Gabriel Rinaldi ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Genome Editing ◽  
Human Macrophage ◽  
Wild Type ◽  
End Joining ◽  
Chromosomal Breakage ◽  
Knock Out ◽  
Guide Rna ◽  
Homology Directed Repair ◽  
Non Homologous End Joining

AbstractCRISPR/Cas9 based genome editing has yet been reported in parasitic or indeed any species of the phylum Platyhelminthes. We tested this approach by targeting omega-1 (ω1) ofSchistosoma mansonias a proof of principle. This secreted ribonuclease is crucial for Th2 priming and granuloma formation, providing informative immuno-pathological readouts for programmed genome editing. Schistosome eggs were either exposed to Cas9 complexed with a synthetic guide RNA (sgRNA) complementary to exon 6 of ω1 by electroporation or transduced with pseudotyped lentivirus encoding Cas9 and the sgRNA. Some eggs were also transduced with a single stranded oligodeoxynucleotide donor transgene that encoded six stop codons, flanked by 50 nt-long 5’-and 3’-microhomology arms matching the predicted Cas9-catalyzed double stranded break (DSB) within ω1. CRISPResso analysis of amplicons spanning the DSB revealed ∼4.5% of the reads were mutated by insertions, deletions and/or substitutions, with an efficiency for homology directed repair of 0.19% insertion of the donor transgene. Transcripts encoding ω1 were reduced >80% and lysates of ω1-edited eggs displayed diminished ribonuclease activity indicative that programmed editing mutated the ω1 gene. Whereas lysates of wild type eggs polarized Th2 cytokine responses including IL-4 and IL-5 in human macrophage/T cell co-cultures, diminished levels of the cytokines followed the exposure to lysates of ω1-mutated schistosome eggs. Following injection of schistosome eggs into the tail vein of mice, the volume of pulmonary granulomas surrounding ω1-mutated eggs was 18-fold smaller than wild type eggs. Programmed genome editing was active in schistosomes, Cas9-catalyzed chromosomal breakage was repaired by homology directed repair and/or non-homologous end joining, and mutation of ω1 impeded the capacity of schistosome eggs both to drive Th2 polarization and to provoke formation of pulmonary circumoval granulomas. Knock-out of ω1 and the impaired immunological phenotype showcase the novel application of programmed gene editing in and functional genomics for schistosomes.

scholarly journals Simultaneous precise editing of multiple genes in human cells

2019 ◽  
Vol 47 (19) ◽  
pp. e116-e116 ◽  
Author(s):  
Stephan Riesenberg ◽  
Manjusha Chintalapati ◽  
Dominik Macak ◽  
Philipp Kanis ◽  
Tomislav Maricic ◽  
...  
Keyword(s):  
Genome Editing ◽  
Kinase Inhibitor ◽  
Double Strand Breaks ◽  
End Joining ◽  
Nucleotide Substitutions ◽  
Strand Breaks ◽  
Homology Directed Repair ◽  
A Genome ◽  
Dependent Protein ◽  
Non Homologous End Joining

Abstract When double-strand breaks are introduced in a genome by CRISPR they are repaired either by non-homologous end joining (NHEJ), which often results in insertions or deletions (indels), or by homology-directed repair (HDR), which allows precise nucleotide substitutions to be introduced if a donor oligonucleotide is provided. Because NHEJ is more efficient than HDR, the frequency with which precise genome editing can be achieved is so low that simultaneous editing of more than one gene has hitherto not been possible. Here, we introduced a mutation in the human PRKDC gene that eliminates the kinase activity of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). This results in an increase in HDR irrespective of cell type and CRISPR enzyme used, sometimes allowing 87% of chromosomes in a population of cells to be precisely edited. It also allows for precise editing of up to four genes simultaneously (8 chromosomes) in the same cell. Transient inhibition of DNA-PKcs by the kinase inhibitor M3814 is similarly able to enhance precise genome editing.

scholarly journals Fast and efficient generation of knock-in human organoids using homology-independent CRISPR/Cas9 precision genome editing

2020 ◽  
Author(s):  
Benedetta Artegiani ◽  
Delilah Hendriks ◽  
Joep Beumer ◽  
Rutger Kok ◽  
Xuan Zheng ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dna Sequences ◽  
Mitotic Spindle ◽  
Cell Types ◽  
Intestinal Cell ◽  
Precise Integration ◽  
Exogenous Dna ◽  
Knock Out ◽  
Homology Directed Repair ◽  
Efficient Generation

AbstractCRISPR/Cas9 technology has revolutionized genome editing and is applicable to the organoid field. However, precise integration of exogenous DNA sequences in human organoids awaits robust knock-in approaches. Here, we describe CRISPR/Cas9-mediated Homology-independent Organoid Transgenesis (CRISPR-HOT), which allows efficient generation of knock-in human organoids representing different tissues. CRISPR-HOT avoids extensive cloning and outperforms homology directed repair (HDR) in achieving precise integration of exogenous DNA sequences at desired loci, without the necessity to inactivate TP53 in untransformed cells, previously used to increase HDR-mediated knock-in. CRISPR-HOT was employed to fluorescently tag and visualize subcellular structural molecules and to generate reporter lines for rare intestinal cell types. A double reporter labelling the mitotic spindle by tagged tubulin and the cell membrane by tagged E-cadherin uncovered modes of human hepatocyte division. Combining tubulin tagging with TP53 knock-out revealed TP53 involvement in controlling hepatocyte ploidy and mitotic spindle fidelity. CRISPR-HOT simplifies genome editing in human organoids.

scholarly journals CRISPR-Cas9: A Genome Editing Tool in Crop Plants: A Review

2021 ◽  
Author(s):  
Varsha Kumari ◽  
Priyanka Kumawat ◽  
Sharanabasappa Yeri ◽  
Shyam Singh Rajput
Keyword(s):  
Genome Editing ◽  
Gene Editing ◽  
Crop Improvement ◽  
End Joining ◽  
Homology Directed Repair ◽  
Ligase Iv ◽  
A Genome ◽  
Target Dna ◽  
Non Homologous End Joining ◽  
Dna Strand

Clustered regularly interspaced short palindromic repeats/CRISPR associated nuclease 9 (CRISPR-Cas9) system is a rapid technology for gene editing. CRISPR-Cas9 is an RNA guided gene editing tool where Cas9 acts as endonuclease by cutting the target DNA strand. Double Stranded Breaks (DBS) can be repaired by non-homologous end joining (NHEJ) and homology-directed repair (HDR). The NHEJ employs DNA ligase IV to rejoin the broken ends which cause insertion or deletion mutations, whereas HDR repairs the DSBs based on a homologous complementary template and results in perfect repair of broken ends. CRISPR-Cas9 impart diverse advantageous features in contrast with the conventional methods. In this review article, we have discussed CRISPR-Cas9 based genome editing along with its mechanism of action and role in crop improvement.

scholarly journals Using Synthetically Engineered Guide RNAs to Enhance CRISPR Genome Editing Systems in Mammalian Cells

2021 ◽  
Vol 2 ◽  
Author(s):  
Daniel Allen ◽  
Michael Rosenberg ◽  
Ayal Hendel
Keyword(s):  
Genome Editing ◽  
Mammalian Cells ◽  
Nuclear Staining ◽  
Two Component System ◽  
Guide Rna ◽  
Homology Directed Repair ◽  
Guide Rnas ◽  
Therapeutic Benefits ◽  
A Genome ◽  
Cas9 Protein

CRISPR-Cas9 is quickly revolutionizing the way we approach gene therapy. CRISPR-Cas9 is a complexed, two-component system using a short guide RNA (gRNA) sequence to direct the Cas9 endonuclease to the target site. Modifying the gRNA independent of the Cas9 protein confers ease and flexibility to improve the CRISPR-Cas9 system as a genome-editing tool. gRNAs have been engineered to improve the CRISPR system's overall stability, specificity, safety, and versatility. gRNAs have been modified to increase their stability to guard against nuclease degradation, thereby enhancing their efficiency. Additionally, guide specificity has been improved by limiting off-target editing. Synthetic gRNA has been shown to ameliorate inflammatory signaling caused by the CRISPR system, thereby limiting immunogenicity and toxicity in edited mammalian cells. Furthermore, through conjugation with exogenous donor DNA, engineered gRNAs have been shown to improve homology-directed repair (HDR) efficiency by ensuring donor proximity to the edited site. Lastly, synthetic gRNAs attached to fluorescent labels have been developed to enable highly specific nuclear staining and imaging, enabling mechanistic studies of chromosomal dynamics and genomic mapping. Continued work on chemical modification and optimization of synthetic gRNAs will undoubtedly lead to clinical and therapeutic benefits and, ultimately, routinely performed CRISPR-based therapies.

scholarly journals TMEPAI genome editing in triple negative breast cancer cells

2017 ◽  
Vol 26 (1) ◽  
pp. 14-8 ◽  
Author(s):  
Bantari W.K. Wardhani ◽  
Meidi U. Puteri ◽  
Yukihide Watanabe ◽  
Melva Louisa ◽  
Rianto Setiabudy ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Line ◽  
Genome Editing ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
High Efficiency ◽  
Knock Out ◽  
Tnbc Cell ◽  
A Genome ◽  
Tnbc Cell Line

Background: Clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9) is a powerful genome editing technique. It consists of RNA-guided DNA endonuclease Cas9 and single guide RNA (gRNA). By combining their expressions, high efficiency cleavage of the target gene can be achieved, leading to the formation of DNA double-strand break (DSB) at the genomic locus of interest which will be repaired via NHEJ (non-homologous end joining) or HDR (homology-directed repair) and mediate DNA alteration. We aimed to apply the CRISPR/Cas9 technique to knock-out the transmembrane prostate androgen-induced protein (TMEPAI) gene in the triple negative breast cancer cell line.Methods: Designed gRNA which targets the TMEPAI gene was synthesized, annealed, and cloned into gRNA expression vector. It was co-transfected into the TNBC cell line using polyethylenimine (PEI) together with Cas9-GFP and puromycin resistant gene vector. At 24-hours post-transfection, cells were selected by puromycin for 3 days before they were cloned. Selected knock-out clones were subsequently checked on their protein levels by western blotting.Results: CRISPR/Cas9, a genome engineering technique successfully knocked-out TMEPAI in the Hs578T TNBC cell line. Sequencing shows a frameshift mutation in TMEPAI. Western blot shows the absence of TMEPAI band on Hs578T KO cells.Conclusion: TMEPAI gene was deleted in the TNBC cell line using the genomic editing technique CRISPR/Cas9. The deletion was confirmed by genome and protein analysis.

scholarly journals Anti-CRISPR-Based and CRISPR-Based Genome Editing of Sulfolobus islandicus Rod-Shaped Virus 2

Viruses ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 695 ◽  
Author(s):  
David Mayo-Muñoz ◽  
Fei He ◽  
Jacob Jørgensen ◽  
Poul Madsen ◽  
Yuvaraj Bhoobalan-Chitty ◽  
...  
Keyword(s):  
Genome Editing ◽  
Selection Marker ◽  
Knock Out ◽  
Viral Propagation ◽  
Functional Studies ◽  
Double Stranded Dna ◽  
Sulfolobus Islandicus ◽  
Knockout Mutants ◽  
A Genome ◽  
Core Genes

Genetic engineering of viruses has generally been challenging. This is also true for archaeal rod-shaped viruses, which carry linear double-stranded DNA genomes with hairpin ends. In this paper, we describe two different genome editing approaches to mutate the Sulfolobus islandicus rod-shaped virus 2 (SIRV2) using the archaeon Sulfolobus islandicus LAL14/1 and its derivatives as hosts. The anti-CRISPR (Acr) gene acrID1, which inhibits CRISPR-Cas subtype I-D immunity, was first used as a selection marker to knock out genes from SIRV2M, an acrID1-null mutant of SIRV2. Moreover, we harnessed the endogenous CRISPR-Cas systems of the host to knock out the accessory genes consecutively, which resulted in a genome comprised solely of core genes of the 11 SIRV members. Furthermore, infection of this series of knockout mutants in the CRISPR-null host of LAL14/1 (Δarrays) confirmed the non-essentiality of the deleted genes and all except the last deletion mutant propagated as efficiently as the WT SIRV2. This suggested that the last gene deleted, SIRV2 gp37, is important for the efficient viral propagation. The generated viral mutants will be useful for future functional studies including searching for new Acrs and the approaches described in this case are applicable to other viruses.

CRISPER/CAS: A potential tool for genomes editing

2021 ◽  
Vol 7 (2) ◽  
pp. 122-129
Keyword(s):  
Genome Editing ◽  
Basic Mechanism ◽  
Zinc Finger Nucleases ◽  
Transcription Activator ◽  
End Joining ◽  
Knock Out ◽  
Homology Directed Repair ◽  
Wide Range ◽  
Non Homologous End Joining ◽  
Cas A

The ability to engineer genomes presents a significant opportunity for applied biology research. In 2050, the population of this world is expected to reach 9.6 billion residents; rising food with better quality is the most promising approach to food security. Compared to earlier methodologies including Zinc Finger Nucleases (ZFNs) plus Transcription Activator-Like Effector Nucleases (TALENs), which were expensive as well as time-consuming, innovation in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and related CRISPR (Cas) protein classifications allowed selective editing of genes for the enhancement of food. The basic mechanism of CRISPR Cas9 process and its applications on genome editing has been summarized in this manuscript. The method relies on Sequence-Specific Nucleases (SSNs) to create Double Stranded Breaks (DSB) of DNA at the locus of genome defined by user, mended by using one of two DNA mending ways: Non-Homologous End Joining (NHEJ) or Homology Directed Repair (HDR). Cas9, an RNA-guided endonuclease, was used to produce stable knock-in and knock-out mutants. The focus of this effort is to explore the CRISPR Cas9 genome editing to manage gene expression and improve future editing success. This adaptable technique can be consumed for a wide range of applications of genome editing requiring high precision. Advances in this technology have sparked renewed interest in the possibilities for editing genome in plants.

scholarly journals Reprogramming acetogenic bacteria with CRISPR-targeted base editing via deamination

2020 ◽  
Author(s):  
Peng-Fei Xia ◽  
Isabella Casini ◽  
Sarah Schulz ◽  
Christian-Marco Klask ◽  
Largus T. Angenent ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dna Cleavage ◽  
Genetically Modified Organisms ◽  
Cytidine Deaminase ◽  
Base Editing ◽  
Homology Directed Repair ◽  
Clostridium Ljungdahlii ◽  
Acetogenic Bacteria ◽  
A Genome ◽  
Nucleotide Resolution

AbstractAcetogenic bacteria are rising in popularity as chassis microbes in biotechnology due to their capability of converting inorganic one-carbon (C1) gases to organic chemicals. To fully uncover the potential of acetogenic bacteria, synthetic-biology tools are imperative to either engineer designed functions or to interrogate the physiology. Here, we report a genome-editing tool at a one-nucleotide resolution, namely base editing, for acetogenic bacteria based on CRISPR-targeted deamination. This tool combines nuclease deactivated Cas9 with activation-induced cytidine deaminase to enable cytosine-to-thymine substitution without DNA cleavage, homology-directed repair, and donor DNA, which are generally the bottlenecks for applying conventional CRISPR-Cas systems in bacteria. We designed and validated a modularized base-editing tool in the model acetogenic bacterium Clostridium ljungdahlii. The editing principles were investigated, and an in-silico analysis revealed the capability of base editing across the genome. Moreover, genes related to acetate and ethanol production were disrupted individually by installing premature STOP codons to reprogram carbon flux towards improved acetate production. This resulted in engineered C. ljungdahlii strains with the desired phenotypes and stable genotypes. Our base-editing tool promotes the application and research in acetogenic bacteria and provides a blueprint to upgrade CRISPR-Cas-based genome editing in bacteria in general.SignificanceAcetogenic bacteria metabolize one-carbon (C1) gases, such as industrial waste gases, to produce fuels and commodity chemicals. However, the lack of efficient gene-manipulation approaches hampers faster progress in the application of acetogenic bacteria in biotechnology. We developed a CRISPR-targeted base-editing tool at a one-nucleotide resolution for acetogenic bacteria. Our tool illustrates great potential in engineering other A-T-rich bacteria and links designed single-nucleotide variations with biotechnology. It provides unique advantages for engineering industrially relevant bacteria without creating genetically modified organisms (GMOs) under the legislation of many countries. This base-editing tool provides an example for adapting CRISPR-Cas systems in bacteria, especially those that are highly sensitive to heterologously expressed Cas proteins and have limited ability of receiving foreign DNA.

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