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CRISPR/Cas9-mediated multiplex gene editing of gamma and omega gliadins: paving the way for gliadin-free wheat.
Wheat is a staple cereal in the human diet. Despite its significance, an increasing percentage of the population suffers adverse reactions to wheat, which are triggered by wheat gluten, particularly the gliadin fractions. In this study, we employed CRISPR/Cas [clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein] multiplexing to introduce targeted mutations into γ- and ω-gliadin genes of wheat, to produce lines deficient in one or both immunogenic gliadin fractions simultaneously. For this study, eight single guide RNAs (sgRNAs) were designed and combined into four plasmids to produce 59 modified wheat lines, of which 20 exhibited mutations in the target genes. Characterization of these lines through Sanger sequencing or next-generation sequencing revealed a complex pattern of InDels, including deletions spanning multiple sgRNAs. The mutations were transmitted to the offspring, and the analysis of homozygous derived lines by reverse-phase HPLC and monoclonal antibodies showed a 97.7% reduction in gluten content. Crossing these lines with other CRISPR/Cas lines deficient in the α-gliadins allowed multiple mutations to be combined. This work represents an important step forward in the use of CRISPR/Cas to develop gluten-free wheat.
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Expanding the range of editable targets in the wheat genome using the variants of the Cas12a and Cas9 nucleases.
The development of CRISPR-based editors recognizing distinct protospacer-adjacent motifs (PAMs), or having different spacer length/structure requirements broadens the range of possible genomic applications. We evaluated the natural and engineered variants of Cas12a (FnCas12a and LbCas12a) and Cas9 for their ability to induce mutations in endogenous genes controlling important agronomic traits in wheat. Unlike FnCas12a, LbCas12a-induced mutations in the wheat genome, even though with a lower rate than that reported for SpCas9. The eight-fold improvement in the gene editing efficiency was achieved for LbCas12a by using the guides flanked by ribozymes and driven by the RNA polymerase II promoter from switchgrass. The efficiency of multiplexed genome editing (MGE) using LbCas12a was mostly similar to that obtained using the simplex RNA guides and showed substantial increase after subjecting transgenic plants to high-temperature treatment. We successfully applied LbCas12a-MGE for generating heritable mutations in a gene controlling grain size and weight in wheat. We showed that the range of editable loci in the wheat genome could be further expanded by using the engineered variants of Cas12a (LbCas12a-RVR) and Cas9 (Cas9-NG and xCas9) that recognize the TATV and NG PAMs, respectively, with the Cas9-NG showing higher editing efficiency on the targets with atypical PAMs compared to xCas9. In conclusion, our study reports a set of validated natural and engineered variants of Cas12a and Cas9 editors for targeting loci in the wheat genome not amenable to modification using the original SpCas9 nuclease.
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Optimized protocols for the characterization of Cas12a activities.
The CRISPR-associated (Cas) Cas12a is the effector protein for type V-A CRISPR systems. Cas12a is a sequence-specific endonuclease that targets and cleaves DNA containing a cognate short signature motif, called the protospacer adjacent motif (PAM), flanked by a 20 nucleotide (nt) segment that is complementary to the "guide" region of its CRISPR RNA (crRNA). The guide sequence of the crRNA can be programmed to target any DNA with a cognate PAM and is the basis for Cas12a's current use for gene editing in numerous organisms and for medical diagnostics. While Cas9 (type II effector protein) is widely used for gene editing, Cas12a possesses favorable features such as its smaller size and creation of staggered double-stranded DNA ends after cleavage that enhances cellular recombination events. Collected here are protocols for the recombinant purification of Cas12a and the transcription of its corresponding programmable crRNA that are used in a variety of Cas12a-specific in vitro activity assays such as the cis, the trans and the guide-RNA independent DNA cleavage activities with multiple substrates. Correspondingly, protocols are included for the quantification of the activity assay data using ImageJ and the use of MATLAB for rate constant calculations. These procedures can be used for further structural and mechanistic studies of Cas12a orthologs and other Cas proteins.
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Versatile electroporation protocols enable reproducible CRISPR-RNP delivery across multiple primary mouse cells of the hematopoietic lineage.
Genetic engineering of primary hematopoietic cells is essential for mechanistic immunology studies, however the development of cell-based therapies yet remains constrained by two major factors: the fragility of many primary lineages and challenges of viral delivery platforms that are costly, time-intensive, and biologically confounding. Here, we optimized scalable CRISPR-Cas9 electroporation workflows using the ExPERT platform across three primary mouse hematopoietic cell types: OT-I CD8+ T cells, bone marrow-derived macrophages (BMDMs), and hematopoietic stem/progenitor cells (HSPCs). In activated OT-I CD8+ T cells, two electroporation programs supported high-efficiency mRNA and RNP delivery with minimal impact on cell viability or proliferative capacity, with subtle activation-state-dependent sensitivity at higher energy settings. Extending optimization to myeloid and stem cell lineages, we found that BMDMs maintained high viability following electroporation, and a high-performing electroporation program supported robust RNP delivery and efficient target gene knockout while preserving macrophage differentiation. In HSPCs, the same program enabled consistent RNP delivery, sustained viability, and reproducible gene knockout. Together, these findings establish ExPERT electroporation as a robust, reproducible, and modular platform for genome editing across primary mouse hematopoietic lineages, lowering barriers to rapid genetic perturbation for both discovery and translational applications. This manuscript has been posted on BioRxiv (https://www.biorxiv.org/content/10.64898/2026.01.27.702081v1).
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Protoplast technology enables the identification of efficient multiplex genome editing tools in Phalaenopsis.
Phalaenopsis orchids are popular ornamental plants worldwide. The application and optimization of efficient CRISPR-Cas genome editing toolkits in Phalaenopsis greatly accelerate the development of orchid gene function and breeding research. However, these methods are greatly hindered by the deficiency of a rapid screening system. In this study, we established a fast and convenient Phalaenopsis protoplast technology for the identification of functional genome editing tools. Two multiplex genome editing tools, PTG-Cas9-HPG (PTG, polycistronic tRNA-gRNA) system and RMC-Cpf1-HPG (RMC, ribozyme-based multi-crRNA) system, were developed for Phalaenopsis genome editing and further evaluated by established protoplast technology. We successfully detected various editing events comprising substitution and indel at designed target sites of the PDS gene and MADS gene, showing that both PTG-Cas9-HPG and RMC-Cpf1-HPG multiplex genome editing systems are functional in Phalaenopsis. Additionally, by optimizing the promoter that drives Cpf1 expression, we found that Super promoter can significantly improve the editing efficiency of the RMC-Cpf1-HPG system. Altogether, we successfully developed two efficient multiplex genome editing systems, PTG-Cas9-HPG and RMC-Cpf1-HPG, for Phalaenopsis, and the established protoplast-based screening technology provides a valuable foundation for developing more diverse and efficient genome editing toolkits and facilitating the development of orchid precision breeding.
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Direct detection of CRISPR-Cas9 ribonucleoprotein gene doping using RNA immunoprecipitation and quantitative PCR.
Gene doping, using technologies such as CRISPR-Cas9, poses a considerable threat to the integrity of sports. In 2018, the World Anti-Doping Agency implemented a ban on genome editing, which highlighted the need for sensitive and specific detection methods. Detection techniques that are currently available have shown effectiveness in specific contexts, but are limited by low sensitivity and short detection windows. To overcome these limitations, this study presents a new detection method for CRISPR-Cas9 ribonucleoprotein (RNP) complexes, termed RNA immunoprecipitation followed by quantitative PCR (RIP-qPCR). The primary focus of this research was the in vitro development of a detection method targeting genes critical for doping, including myostatin (MSTN), α-actinin 3 (ACTN3), erythropoietin receptor (EPOR), and erythropoietin (EPO), with in vivo proof-of-concept demonstrated using MSTN. The RIP-qPCR method demonstrated sensitive performance, with a limit of quantification of 0.1 ng/mL in plasma. This method successfully detected single guide RNA targeting MSTN, ACTN3, EPOR, and EPO, along with two types of Cas9 proteins in RNP complexes in vitro. Additionally, the detection capabilities of RIP-qPCR were maintained for up to 30 days when plasma samples were stored at 4 °C. In vivo experiments were performed where RNPs were administered via intramuscular and intravenous injections to target the murine Mstn gene. CRISPR-Cas9 RNPs remained detectable for up to 24 h following intramuscular injection and 12 h after intravenous injection. This study underscores the potential of RIP-qPCR as a powerful tool for anti-doping analysis, with future efforts on expanding the target gene panel to enhance the detection of gene editing in sports doping.
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Establishment and application of a silkworm CRISPR/Cas9 tool for conditionally manipulating gene disruption in the epidermis.
Spatial or temporal specific gene knockout system is a valuable tool for studying the molecular mechanisms underlying developmental processes. The integument is essential for insect fitness and survival, but tools for dissecting function of genes in this tissue are lacking. In this study, we firstly identified an epidermis specifically expressed gene of the domesticated silkworm, BmCPG25, by comparative transcriptomic analysis. Furthermore, a transgenic silkworm expressing the RNA dependent CRISPR-Cas9 protein driven by the regulatory region of the BmCPG25 was established. Immunochemistry analysis showed the endonuclease was specifically expressed in the nuclear of epidermal cells. We also validated the efficiency of this system by disrupting the function of an epidermis specifically expressed cuticular protein gene (Cpr21) and a ubiquitously expressed cuticular gene (Cph18), respectively. In summary, we successfully constructed a conditional knockout toolkit to manipulate the gene editing in epidermal cells, which provides a valuable approach to study the molecular mechanism of integument development.
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Single and combinatorial gene inactivation in Aspergillus niger using selected as well as genome-wide gRNA library pools.
Aspergillus niger is a saprotroph, a pathogen, an endophyte, a food spoiler and an important cell factory. Only a minor fraction of its genes has been experimentally characterized. We here set up a CRISPR/Cas9 mutagenesis screen for functional gene analysis using co-transformation of a pool of gene editing plasmids that are maintained under selection pressure and that each contain a gRNA. First, a pool of gRNA vectors was introduced in A. niger targeting five genes with easy selectable phenotypes. Transformants were obtained with all possible single, double, triple, quadruple and quintuple gene inactivation phenotypes. Their genotypes were confirmed using the gRNA sequences in the transforming vector as barcodes. Next, a gRNA library was introduced in A. niger targeting > 9600 genes. Gene nsdC was identified as a sporulation gene using co-transformation conditions that favored uptake of one or two gRNA construct(s) from the genome-wide vector pool. Together, CRISPR/Cas9 vectors with a (genome-wide) pool of gRNAs can be used for functional analysis of genes in A. niger with phenotypes that are the result of the inactivation of a single or multiple genes.
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Improving Precise Genome Editing Using Donor DNA/gRNA Hybrid Duplex Generated by Complementary Bases.
In precise genome editing, site-specific DNA double-strand breaks (DSBs) induced by the CRISPR/Cas9 system are repaired via homology-directed repair (HDR) using exogenous donor DNA templates. However, the low efficiency of HDR-mediated genome editing is a barrier to widespread use. In this study, we created a donor DNA/guide RNA (gRNA) hybrid duplex (DGybrid) that was composed of sequence-extended gRNA and single-stranded oligodeoxynucleotide (ssODN) combined with complementary bases without chemical modifications to increase the concentration of donor DNA at the cleavage site. The efficiency of genome editing using DGybrid was evaluated in Saccharomyces cerevisiae. The results show a 1.8-fold (from 35% to 62%) improvement in HDR-mediated editing efficiency compared to genome editing in which gRNA and donor DNA were introduced separately. In addition, analysis of the nucleic acid introduction efficiency using flow cytometry indicated that both RNA and ssODNs are efficiently incorporated into cells together by using the DNA/RNA hybrid. Our technique would be preferred as a universal and concise tool for improving the efficiency of HDR-mediated genome editing.
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Improved CRISPR/Cas9 gene editing by fluorescence activated cell sorting of green fluorescence protein tagged protoplasts.
BACKGROUND: CRISPR/Cas9 is widely used for precise genetic editing in various organisms. CRISPR/Cas9 editing may in many plants be hampered by the presence of complex and high ploidy genomes and inefficient or poorly controlled delivery of the CRISPR/Cas9 components to gamete cells or cells with regenerative potential. Optimized strategies and methods to overcome these challenges are therefore in demand. RESULTS: In this study we investigated the feasibility of improving CRISPR/Cas9 editing efficiency by Fluorescence Activated Cell Sorting (FACS) of protoplasts. We used Agrobacterium infiltration in leaves of Nicotiana benthamiana for delivery of viral replicons for high level expression of gRNAs designed to target two loci in the genome, NbPDS and NbRRA, together with the Cas9 nuclease in fusion with the 2A self-splicing sequence and GFP (Cas9-2A-GFP). Protoplasts isolated from the infiltrated leaves were then subjected to FACS for selection of GFP enriched protoplast populations. This procedure resulted in a 3-5 fold (from 20 to 30% in unsorted to more than 80% in sorted) increase in mutation frequencies as evidenced by restriction enzyme analysis and the Indel Detection by Amplicon Analysis, which allows for high throughput profiling and quantification of the generated mutations. CONCLUSIONS: FACS of protoplasts expressing GFP tagged CRISPR/Cas9, delivered through A. tumefaciens leaf infiltration, facilitated clear CRISPR/Cas9 mediated mutation enrichment in selected protoplast populations.
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