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Found: 26 174
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CRISPR-Cas9 engineering in the hybrid yeast Zygosaccharomyces parabailii can lead to loss of heterozygosity in target chromosomes.
The hybrid yeast Zygosaccharomyces parabailii holds potential as a cell factory mainly because of its robustness in withstanding stressors that often characterize bio-based processes. However, a complex genome and a lack of gene editing tools hinder the capacity to engineer this yeast. In this work, we developed a CRISPR-Cas9 gene editing system for Z. parabailii that allows simultaneous disruption or deletion of both alleles of a gene. We evaluated four different gRNA expression systems consisting of combinations of tRNAs, tRNA and ribozyme or ribozymes as self-cleaving flanking elements and established that the most efficient systems used an RNA Pol II promoter followed by a 5'tRNA flanking the gRNA. This gRNA system was then used to construct a strain of Z. parabailii in which both alleles of DNL4 were inactivated and so relied on homologous recombination to repair double-stranded breaks. Our system can be used for gene inactivation in a wild-type strain and precise deletion with marker insertion in a dnl4 mutant. In some cases, we observed inter-chromosomal recombination around the site of the DSB that could cause loss of heterozygosity through gene conversion or deletion. Although an additional aspect that needs to be monitored during strain engineering, this phenomenon also offers opportunities to explore genome plasticity in hybrid yeasts.
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A Myostatin (MSTN-/-) Knockout Buffalo Produced by CRISPR-Cas9 Mediated Genome Editing and Somatic Cell Nuclear Transfer.
CRISPR-Cas9 genome editing offers significant opportunities to improve livestock traits; however, its application in buffalo has been very limited, with no prior reports of live gene-edited animals. Here, we report the successful birth of a buffalo edited in the myostatin (MSTN) gene. To achieve this, five single-guide RNAs (sgRNAs) targeting the buffalo MSTN gene were designed and tested in skin-derived fibroblasts. Among these, sgRNA5 exhibited the highest editing efficiency, approaching ∼50%, as confirmed by T7 Endonuclease I assay, Tracking of Indels by Decomposition, and Inference of CRISPR Edits analyses. Single-cell cloning identified six edited fibroblast clonal populations, including one with a bi-allelic frameshift mutation predicted to severely truncate the MSTN protein. These bi-allelic clonal cells were subsequently used as nuclear donors to produce somatic cell nuclear transfer (SCNT) embryos, which were transferred into recipient buffaloes (n = 15). This effort established three pregnancies and resulted in the birth of one live MSTN knockout buffalo calf. Phenotypically, the calf displayed accelerated growth and increased muscle fiber number and size while maintaining normal meat composition. In conclusion, this study reports the world's first gene-edited buffalo generated through CRISPR-Cas9-mediated genome editing combined with SCNT. These findings provide a proof-of-concept for genome editing in buffalo and demonstrate that MSTN disruption can effectively enhance muscle growth and meat production traits.
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[Improving the Efficiency and Safety of Human CCR5 Gene Editing by Selection of Optimal Guide RNAs for SpCAS9 and CAS12A].
Advances in CRISPR/Cas-mediated genome editing have opened up treatment alternatives for many human diseases, including HIV infection. Knockout of the CCR5 gene as a potential way to treat HIV infection has long been studied. Here we analyzed guide RNAs for SpCas9 and AsCas12a nucleases targeting CCR5 gene which had been previously studied and selected the most effective among them. We also designed novel guide RNAs for the same nucleases using bioinformatics resources. We compared the efficiency of target site cleavage for all selected gRNAs using three nucleases: wt SpCas9, SpCas9-HF1-plus, and AsCas12a, as well as their off- target activities. We demonstrated that among the tested guide RNAs two for SpCas9- HF1-plus and three for AsCas12a exhibited high cleavage activity, cutting CCR5 gene in 60-72% of cells, and had off-target activities below the limit of detection. Thus, these guide RNAs may be candidates for future development of gene therapies against HIV infection.
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CRISPR/Cas genome editing in plants: Dawn of Agrobacterium transformation for recalcitrant and transgene-free plants for future crop breeding.
Genome editing tools based on CRISPR/Cas system have been posed to solve many issues in agriculture and improve food production. Genetic engineering by Agrobacterium-mediated transformation has helped to impart specific traits straightaway in many crops. Many GM crops have also reached the field for commercial cultivation. Genetic engineering requires mostly a transformation protocol often mediated by Agrobacterium to insert a specific gene at a random locus. Genome editing with CRISPR/Cas system is a more precise technique for the targeted modification of genes/bases in the host plant genome. Unlike the conventional transformation system, wherein elimination of marker/foreign gene was possible only post-transformation, CRISPR/Cas system could generate transgene-free plants by delivering CRISPR/Cas reagents such as the Cas protein and guide RNAs gRNA(s) preassembled to form ribonucleoproteins (RNPs) into plant cells. CRISPR reagent delivery might be helpful to overcome issues with plants that are recalcitrant to Agrobacterium transformation and the legal hurdles due to the presence of the foreign gene. More recently, the grafting of wild-type shoots to transgenic donor rootstocks developed by the CRISPR/Cas system has reported transgene-free genome editing. CRISPR/Cas system also requires only a small piece of gRNA besides Cas9 or other effectors to target a specific region in the genome. So this system has been projected to be a key contributor to future crop breeding. In this article, we recap the main events of plant transformation, compare the difference between genetic transformation and CRISPR/Cas-mediated genome editing, and draw insights into the future application of the CRISPR/Cas system.
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CRISPR based genome editing and removal of human viruses.
The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated proteins 9 (Cas9), a gene-editing technology, has been extensively applied as a tool for genetic engineering in basic research. Efficient genome engineering has been performed in viruses, human cells, bacteria, fungi, plants and animals, etc. Currently, it has been employed to edit human viruses for studying viral molecular biology, pathogenesis and oncogenesis, and facilitate the development of antiviral agents and vaccine. The virus is ubiquitous worldwide and elicits global health problems, many human diseases are associated with virus infections. Although traditional drugs can be used to treat or prevent productive viral infections, their efficacy is limited because of toxicity, side effects and other problems. Additionally, no current drugs are approved to be indicated for latent infections. Therefore, the next highlight is to develop antiviral approaches to against both productive and latent infections. Fortunately, CRISPR has been successfully applied in the removal of human viruses ex vivo and/or in vivo, and has the potential to be used to manufacture antiviral agents for clinical application. CRISPR/Cas9 is promising in applications, even though some technical challenges, safety concerns, ethic concerns need to be improved. In this article, the discovery and application of genome editing and removal of human viruses based on CRISPR are explored. Additionally, we evaluate the prospects and limitations of this novel antiviral strategies.
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CRISPR/Cas bioimaging: From whole body biodistribution to single-cell dynamics.
This review explores the transformative role of CRISPR/Cas systems in optical bioimaging, emphasizing how advancements in nanoparticle (NP) technologies are revolutionizing the visualization of gene-editing processes both in vitro and in vivo. Optical imaging techniques, such as near-infrared (NIR) and fluorescence imaging, have greatly benefited from the integration of nanoformulated contrast agents, improving resolution, sensitivity, and specificity. CRISPR/Cas systems, originally developed just for gene editing, are now being coupled with these imaging modalities to enable real-time monitoring and quantitative measurements of metabolites, vitamins, proteins, nucleic acids and other entities in specific areas of the body, as well as tracking of CRISPR/Cas delivery, editing efficiency, and potential off-target effects. The development of CRISPR/Cas-loaded NPs allows for enhanced imaging and precise monitoring across multiple scales with multiplexed and multicolor imaging in complex settings, including potential in vivo diagnostics. CRISPR/Cas therapeutics as well as diagnostics are hindered by the lack of efficient and targeted delivery tools. Biomimetic NPs have emerged as promising tools for improving biocompatibility, enhancing targeting capabilities, and overcoming biological barriers, facilitating more efficient delivery and bioimaging of CRISPR/Cas systems in vivo. As the design of these NPs and delivery mechanisms improves, alongside advancements in endolysosomal escape, CRISPR/Cas-based bioimaging will continue to advance, offering unprecedented possibilities in precision medicine and theranostic applications.
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The genetics of intellectual disability: advancing technology and gene editing.
Intellectual disability (ID) is a neurodevelopmental condition affecting 1-3% of the world's population. Genetic factors play a key role causing the congenital limitations in intellectual functioning and adaptive behavior. The heterogeneity of ID makes it more challenging for genetic and clinical diagnosis, but the advent of large-scale genome sequencing projects in a trio approach has proven very effective. However, many variants are still difficult to interpret. A combined approach of next-generation sequencing and functional, electrophysiological, and bioinformatics analysis has identified new ways to understand the causes of ID and help to interpret novel ID-causing genes. This approach offers new targets for ID therapy and increases the efficiency of ID diagnosis. The most recent functional advancements and new gene editing techniques involving the use of CRISPR-Cas9 allow for targeted editing of DNA in in vitro and more effective mammalian and human tissue-derived disease models. The expansion of genomic analysis of ID patients in diverse and ancient populations can reveal rare novel disease-causing genes.
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CRISPR/Cas9-mediated genome editing in Penicillium oxalicum and Trichoderma reesei using 5S rRNA promoter-driven guide RNAs.
OBJECTIVE: To construct convenient CRISPR/Cas9-mediated genome editing systems in industrial enzyme-producing fungi Penicillium oxalicum and Trichoderma reesei. RESULTS: Employing the 5S rRNA promoter from Aspergillus niger for guide RNA expression, the β-glucosidase gene bgl2 in P. oxalicum was deleted using a donor DNA carrying 40-bp homology arms or a donor containing no selectable marker gene. Using a markerless donor DNA as editing template, precise replacement of a small region was achieved in the creA gene. In T. reesei, the A. niger 5S rRNA promoter was less efficient than that in P. oxalicum when used for gene editing. Using a native 5S rRNA promoter, stop codons were introduced into the lae1 coding region using a markerless donor DNA with an editing efficiency of 36.67%. CONCLUSIONS: Efficient genome editing systems were developed in filamentous fungi P. oxalicum and T. reesei by using heterologous or native 5S rRNA promoters for guide RNA expression.
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Introduction of a point mutation in the KRAS gene of in vitro fertilized porcine zygotes via electroporation of the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides.
This study aimed to investigate the efficiency of KRAS gene editing via CRISPR/Cas9 delivery by electroporation and analyzed the effects of the non-homologous end-joining pathway inhibitor Scr7 and single-stranded oligodeoxynucleotide (ssODN) homology arm length on introducing a point mutation in KRAS. Various concentrations (0-2 µM) of Scr7 were evaluated; all concentrations of Scr7 including 0 µM resulted in the generation of blastocysts with a point mutation and the wild-type sequence or indels. No significant differences in the blastocyst formation rates of electroporated zygotes were observed among ssODN homology arm lengths, irrespective of the gRNA (gRNA1 and gRNA2). The proportion of blastocysts carrying a point mutation with or without the wild-type sequence and indels was significantly higher in the ssODN20 group (i.e., the group with a ssODN homology arm of 20 bp) than in the ssODN60 group (gRNA1: 25.7% vs. 5.4% and gRNA2: 45.5% vs. 5.9%, p < .05). In conclusion, the CRISPR/Cas9 delivery with ssODN via electroporation is feasible for the generation of point mutations in porcine embryos. Further studies are required to improve the efficiency and accuracy of the homology-directed repair.
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In vivo DNA methylation editing in zebrafish.
The CRISPR/dCas9-based epigenome editing technique has driven much attention. Fused with a catalytic domain from Dnmt or Tet protein, the CRISPR/dCas9-DnmtCD or -TetCD systems possess the targeted DNA methylation editing ability and have established a series of in vitro and in vivo disease models. However, no publication has been reported on zebrafish (Danio rerio), an important animal model in biomedicine. The present study demonstrated that CRISPR/dCas9-Dnmt7 and -Tet2 catalytic domain fusions could site-specifically edit genomic DNA methylation in vivo in zebrafish and may serve as an efficient toolkit for DNA methylation editing in the zebrafish model.
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