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At least 19 recordsLinked to original sources
PubMed2025

Engineering and comparison of cas12a-based genome editing systems in plants.

While Cas9 and Cas12a are both RNA-guided endonucleases used for genome editing, only Cas12a is able to process pre-crRNA via its additional ribonuclease activity. This feature reduces the complexity of Cas12a versus Cas9-based genome editing systems thus providing an attractive alternative for generating site-specific mutations in plants. Here we aimed to improve the efficiency of the cas12a-based generation of two double-strand breaks flanking the open reading frame of a target gene, leading to its full deletion. To this end, we compared the relative impact of different components on cas12a-based gene deletion efficiency in three different eudicotyledons, Arabidopsis thaliana, Lotus japonicus, and Nicotiana benthamiana. We detected the highest cas12a-based editing efficiency with a combination of suitable promoters for crRNA and cas12a expression, a tandem terminator to control cas12a expression, a re-coded cas12a, adapted to the codon usage of Arabidopsis and engineered to carry introns, and encoding a Cas12a flanked by a nuclear localization signal at both ends. Our work revealed the high potential for improving cas12a-based genome editing systems for plant genetic research.

Gene Editing↗
PubMed2026

Enhancing CRISPR-Cas12a base editing in plants with LbCas12a variants and introns.

Cytosine base editors (CBEs) and adenine base editors (ABEs) are powerful tools for precise genome editing in plants. Conventionally, such base editors are built upon the CRISPR-Cas9 systems where Cas9 nickases are used. To expand the base editing scope and minimize off-target effects, base editors derived from the CRISPR-Cas12a systems are desired. However, the use of deactivated Cas12a (dCas12a) in such base editors constrains the editing activity, preventing the wide use of Cas12a base editors for plant research and trait development. In this study, we demonstrate the use of an ABE based on the efficient LbCas12a-RRV variant to introduce herbicide-resistant mutations in OsACCase in rice. To improve Cas12a CBEs and ABEs, we inserted introns into the coding sequence of dLbCas12a-RRV. This intron-containing Cas12a-CBE shows substantial improvement in editing efficiency in rice, compared to the intron-less counterparts. By contrast, the improvement of ABE with the intron-containing dLbCas12a-RRV is very limited, partly due to the already high baseline editing efficiency of the intron-less dLbCas12a-RRV ABE. Testing of these base editors in poplar shows elevated C-to-T base editing by dLbCas12a-RRV-intron-CBE. For A-to-G editing, ABEs built upon dLbCas12a-RV and dLbCas12a-RRV variants showed significant improvement over ABEs derived from wild-type LbCas12a and the ttLbCas12a variant. The addition of introns to dLbCas12a-RRV does not further improve the base editing efficiency. With whole genome sequencing in rice, we evaluated genome editing specificities with these improved Cas12a base editors. Our analyses show that both intron-containing Cas12a CBE and ABE barely introduce guide RNA-dependent off-target mutations. However, they can generate guide RNA-independent off-target mutations, which are likely attributed to the high enzymatic activities of the deaminases. Collectively, our study demonstrates the successful use of a Cas12a base editor for trait development and reports improved Cas12a CBEs and ABEs for precise base editing in plants.

Oryza↗
PubMed2026

Development and evaluation of a one-pot RPA-Cas12a assay based on a primer-driven reverse screening strategy for preliminary screening of megalocytivirus-related viruses.

A primer-driven reverse-screening strategy was used to identify an RPA-Cas12a target suitable for the rapid preliminary screening of megalocytivirus-related viruses. The ISKNV reference genome NC_003494.1 was used as the initial template, and candidate amplification units were designed according to RPA primer-design requirements, primer physicochemical properties, and the availability of Cas12a protospacer-adjacent motif (PAM) sites and crRNA target sequences. Following preliminary amplification assessment, the retained candidate primers were aligned individually against 75 complete genome sequences of megalocytivirus-related viruses. Of these, 67 sequences met the predefined criteria for target-region integrity, primer-binding-site compatibility, and Cas12a recognition. Retrospective mapping to the reference genome located the candidate amplification region within ORF057L. Based on the resulting candidate detection unit, a one-pot RPA-Cas12a assay incorporating a commercially available lyophilized RPA amplification module was developed. Optimization showed that 400 nM reporter and 80 nM crRNA-1 provided relatively stable fluorescence output. A cut-off value of 1281.6 relative fluorescence units (RFU) was established as the mean plus three standard deviations of the endpoint fluorescence values obtained from 20 qPCR-negative samples. In analytical sensitivity testing, the assay generated fluorescence signals above the negative control at low plasmid copy numbers. However, because only a limited number of replicates were tested at these low template concentrations, these findings were not used to define a formal limit of detection. ISKNV, RSIV, and TRBIV samples tested positive, whereas the MRV sample produced an endpoint fluorescence value below the cut-off. Repeatability analysis of the same sample in six independent reactions yielded a coefficient of variation of 8.03%. Among the 39 samples examined, no discordant qualitative results were observed between the RPA-Cas12a assay and qPCR. These findings support the use of the ORF057L-targeted one-pot RPA-Cas12a assay as a rapid preliminary screening tool for megalocytivirus-related viruses. Nevertheless, its formal limit of detection, inter-batch stability, cross-reactivity with additional non-target pathogens, and clinical diagnostic performance require further evaluation.

Lyophilized RPA↗
PubMed2026

Active-site arginines differentially control Cas12a DNA cleavage and specificity.

Cas12a is a CRISPR-Cas nuclease with biochemical features that make it useful for genome editing and nucleic acid diagnostics. However, its off-target and non-specific trans and CRISPR RNA-independent DNA cleavages can reduce the accuracy and limit applications requiring high fidelity. Here, we analyzed the role of two conserved arginine residues, R918 and R921, found in the RuvC active site pocket of Francisella novicida Cas12a. Through amino acid substitutions, biochemical assays, kinetic analysis, and computational study, we establish that a positive charge at 921 is required for CRISPR RNA-dependent DNA cleavage (cis cleavage), whereas R918 primarily enhances cleavage efficiency. Replacing R918 with lysine or alanine eliminates trans activity while retaining cis cleavage, whereas replacing R921 with lysine eliminates trans activity and replacing with alanine abolishes cis and trans cleavages. Furthermore, these changes significantly decrease RNA-independent cleavage and improve mismatch discrimination during cis cleavage, especially at PAM-distal sites. Structural analysis shows that R918 assists in the conversion of the lid covering the RuvC active site to an alpha helical form, while R921 stabilizes the DNA in the active site. Molecular dynamics simulations reveal that while R921 is critical in supporting the positioning of scissile phosphate, R918 is essential in maintaining catalytic-site organization through lid's conformational change as well as in positioning DNA through its role in stabilizing the active site framework. Together, our results highlight the importance of R918 and R921 in Cas12a's activity and the potential of modifying active pocket residues to reduce unwanted DNA cleavage while increasing on-target specificity.

CRISPR-Cas↗
PubMed2025

Gene Editing and Protein Tagging in the Oomycete Phytophthora infestans Using CRISPR-Cas12a.

Molecular genetic tools such as CRISPR-Cas gene editing systems are invaluable for understanding gene and protein function and revealing the details of a pathogen's life and disease cycles. Here we present protocols for genome editing in Phytophthora infestans, an oomycete with global importance as a pathogen of potato and tomato. Using a vector system that expresses variants of Cas12a from Lachnospiraceae bacterium and its guide RNA from a unified transcript, we first present a method for editing genes through the non-homologous end-joining (NHEJ) pathway. We then describe an application of homology-directed repair (HDR), in which Cas12a is used to fuse a protein-coding gene with a fluorescent or epitope tag. Both methods should be adaptable to many oomycetes other than P. infestans.

Gene Editing↗
PubMed2025

Efficient and multiplexed somatic genome editing with Cas12a mice.

Somatic genome editing in mouse models has increased our understanding of the in vivo effects of genetic alterations. However, existing models have a limited ability to create multiple targeted edits, hindering our understanding of complex genetic interactions. Here we generate transgenic mice with Cre-regulated and constitutive expression of enhanced Acidaminococcus sp. Cas12a (enAsCas12a), which robustly generates compound genotypes, including diverse cancers driven by inactivation of trios of tumour suppressor genes or an oncogenic translocation. We integrate these modular CRISPR RNA (crRNA) arrays with clonal barcoding to quantify the size and number of tumours with each array, as well as the impact of varying the guide number and position within a four-guide array. Finally, we generate tumours with inactivation of all combinations of nine tumour suppressor genes and find that the fitness of triple-knockout genotypes is largely explainable by one- and two-gene effects. These Cas12a alleles will enable further rapid creation of disease models and high-throughput investigation of coincident genomic alterations in vivo.

Animals↗
PubMed2026

Engineering bubble structures as Cas12a activators for highly sensitive monitoring of WRN helicase function.

The Werner syndrome helicase (WRN) is a critical synthetic lethal target in microsatellite instability cancers, essential for resolving complex genomic structures like replication bubbles and R-loops. However, strategies to simultaneously discriminate WRN activity on DNA versus DNA-RNA substrates in living cells are lacking. Here, we developed a structure-specific CRISPR/Cas12a biosensing strategy to visualize WRN functional activity by engineering bubble-structure probes. These probes were rationally designed to structurally mimic DNA replication bubbles and R-loop associated DNA-RNA hybrids. Upon specific unwinding by WRN, the probes release a sequestered activator strand that triggers Cas12a trans-cleavage, effectively converting the unwinding event into an amplified fluorescent signal. This assay achieves low picomolar sensitivity (LODs: 5.6-6.0 pM) and exceptional selectivity against homologous RecQ helicases. Uniquely, this strategy enables the parallel quantification of WRN activity on both substrate types, providing insights into distinct WRN-mediated pathways for resolving genomic stress. We further demonstrated the strategy's utility by visualizing endogenous WRN dynamics in living cells and profiling the efficacy of small-molecule inhibitors. This work offers a powerful molecular toolkit for dissecting WRN biology and facilitating high-throughput drug screening in targeted cancer therapy.

Werner Syndrome Helicase↗
PubMed2025

Versatile and Portable Cas12a-mediated Detection of Antibiotic Resistance Markers.

Antibiotic-resistant bacteria are spreading in clinical, industrial, and environmental ecosystems. The spreading dynamics to and from the environment are unknown, largely due to the lack of appropriate (robust, fast, low-cost) analytical assays. In this study, we developed C12a, a versatile molecular toolbox to detect genetic markers of antibiotic resistance using CRISPR/Cas12a. Biochemical characterization show that the C12a toolbox can detect less than 100 attoMolar of pure DNA fragments from the blaCTX-M15 and floR genes, conferring resistance to b-lactams and amphenicols, respectively important for human and veterinary uses. In microbiological assays, C12a detected less than 102 CFU/mL and high concordance was observed if compared to antibiotic susceptibility tests, PCR, or to whole genome sequencing. Additionally, C12a confirmed a high prevalence of the integrase/integron system in E. coli isolates containing multiple antibiotic resistance genes (ARGs). The C12a toolbox shows equivalent detection performance in diverse laboratory settings, results redout (Fluorescence vs FLA) or input sample. Altogether, this work presents a comprehensive proof-of-concept, development description, and biochemical characterization of a collection of molecular tools to detect antibiotic resistance markers in a one health setup.

Antibiotic Resistance Gene↗
PubMed2026

Rapid CRISPR-based bovine embryo sexing to streamline genotype-informed cattle breeding.

Cattle in vitro fertilisation and embryo transfer programmes increasingly rely on embryo-level selection to accelerate genetic gain, but current sexing and genotyping workflows can be costly, slow and logistically demanding. This study developed an efficient, low-resource workflow for bovine embryo sexing that combines whole genome amplification (WGA) with recombinase polymerase amplification-CRISPR-Cas12a (RPA-Cas12a). It also assessed whether the same WGA biopsy products could be used for downstream single nucleotide polymorphism (SNP) microarray genotyping. A one-tube RPA-Cas12a assay targeting the bovine Y-chromosome S4 repeat was developed for fluorescence and lateral flow assay (LFA) readouts. Analytical sensitivity was assessed using serially diluted bovine genomic DNA (gDNA), and breed robustness was tested using male and female gDNA from five major beef breeds and Holstein cattle. The workflow was then applied to WGA products from 22 bovine blastocyst biopsies, with sex calls validated against an established real-time PCR melt curve assay and 100K SNP microarray genotyping. The assay detected male bovine gDNA down to 100 pg using both fluorescence and LFA readouts, with no signal from female gDNA. Male-specific detection was consistent across all breeds tested. All WGA-RPA-Cas12a sex calls from blastocyst biopsies were concordant with real-time PCR and SNP microarray sex calls, and WGA biopsy products produced genome-wide SNP call rates above 85%. This workflow provides a practical approach for rapid bovine embryo sex triage and could reduce unnecessary cryopreservation and genotyping while improving the efficiency of genotype-informed cattle breeding programmes.

Bovine embryo↗
PubMed2026

Monitoring kinetic changes and restriction of influenza A virus RNA species during infection using a Flu-Stranded CRISPR platform.

UNLABELLED: Influenza A virus (IAV) generates three closely related RNA species: viral RNA (vRNA), complementary RNA (cRNA), and messenger RNA (mRNA), whose strand-specific quantification remains limited by sensitivity and quantitative dynamic range, particularly at low RNA abundance. Here, we developed Flu-Stranded CRISPR-Cas12a, a strand-specific detection platform integrating tagged reverse transcription, segment-specific PCR, and Cas12a collateral cleavage to support quantitative analysis of all three RNA species across a broad dynamic range. The assay enables reliable detection down to 102 copies per reaction, extending the lower quantitative boundary relative to both SYBR Green and TaqMan reverse transcription quantitative PCR (RT-qPCR) under matched conditions. Validated in infected cell lines, murine lung tissues, and clinical nasopharyngeal specimens, the platform enabled subtype-discriminating, strand-resolved detection, including samples near or below the quantitative range of SYBR Green RT-qPCR. Using finely resolved infection time-course analyses in NP and NA segments, we identified a reproducible early vRNA decline within the early post-infection phase. This decline was partially attenuated in RIG-I knockout A549 cells, while subsequent vRNA accumulation was enhanced, consistent with a modulatory rather than essential role for RIG-I in early viral RNA dynamics. Subcellular fractionation localized this decline to cytoplasmic incoming genomes. In contrast, importazole-mediated inhibition of nuclear import abolished vRNA recovery without affecting the early decline, indicating that nuclear entry functionally separates early genome reduction from subsequent productive replication. These findings establish Flu-Stranded CRISPR-Cas12a as a strand-resolved framework for monitoring IAV RNA dynamics and reveal an early window of genome vulnerability during cytoplasmic transit that shapes infection outcome. IMPORTANCE: The early fate of incoming influenza virus genomes remains unclear, limiting our understanding of how infection is established or aborted in host cells. We developed Flu-Stranded CRISPR-Cas12a, a strand-specific platform for sensitive and quantitative analysis of influenza viral RNA (vRNA), complementary RNA (cRNA), and messenger RNA (mRNA) across experimental and clinical samples. Using high-resolution time-course analysis, we identified a reproducible early decline in vRNA during the post-entry phase. Our data suggest that this early genome loss arises from multiple processes, with RIG-I acting as a modulatory factor rather than a primary driver. Subcellular fractionation localized this effect to cytoplasmic incoming genomes, whereas importin-β-mediated nuclear entry was required for subsequent vRNA recovery. These findings support a model of an early cytoplasmic phase of genome attrition that is distinct from replication and provide a framework for understanding early influenza RNA kinetics and for guiding strand-resolved diagnostics and antiviral evaluation.

CRISPR-Cas12a↗
PubMed2025

Analysis of metal-dependent DNA nicking activities by Cas endonucleases.

CRISPR-Cas systems use RNA-guided CRISPR-associated (Cas) effectors to neutralize infections in bacteria and archaea. In class 2 CRISPR-Cas systems, Cas9 and Cas12 are single-protein Cas effectors that target double-stranded DNA based on complementarity to the guide RNA before cleaving the target DNA using metal-dependent endonuclease domains. Cas9 and Cas12 proteins can be readily programmed to target any DNA of interest by changing the guiding RNA sequence and have been co-opted for genome editing and other biotechnology purposes. The effect of metal ion concentration is an essential consideration in the physiological role of Cas immunity effectors as well as the biotechnological applications of Cas endonucleases. In this chapter, we describe methods for studying the effect of variable divalent metal ion conditions on the DNA binding and cleavage activities of well-studied Cas9 and Cas12a proteins.

CRISPR-Cas Systems↗
PubMed2026

Expanding the scope of precision editing in seaweeds through the application of a novel CRISPR-associated nuclease 12a-aligned CRISPR system in Ulva prolifera.

Seaweeds, such as the fast-growing green alga Ulva prolifera, can be harnessed as valuable marine crops. The lack of scalable genome-editing tools hampers functional genomics to explore and elucidate algal molecular pathways with industrial importance. Here, we expanded precision genome modification in seaweeds by successfully demonstrating gene editing with a transgene-free AT-rich-targeting CRISPR-associated protein (Cas) system in U. prolifera. By evaluating various delivery buffers, comparing different Cas systems, and optimizing incubation temperatures, we determined suitable conditions for more widespread applicability of a novel Cas12a-aligned ST8 editor. We obtained >50 ST8-mediated knockout mutants of a toxin-based endogenous marker gene, UpAPT, at 28 °C post-delivery incubations. Our work diversified the applicable genome-editing tools in seaweeds, advancing algal functional genomics and providing more strategies to precisely target unexplored seaweed resources.

Ulva↗
PubMed2026

A CRISPR-Based Rapid Detection Assay for Crayfish Plague (Aphanomyces astaci) From Environmental Samples.

Crayfish plague, caused by Aphanomyces astaci (Aa), is an infectious disease invasive in Europe, where its rapid spread has resulted in sharp declines of native crayfish species. Monitoring currently relies on a highly sensitive, but costly and time-consuming qPCR approach. Here, we designed a simplified, rapid and cost-efficient molecular assay for on-site detection of Aa. The novel rapid assay employs a combination of isothermal recombinase polymerase amplification and CRISPR-Cas12a-based detection that can be coupled with fluorescence or lateral flow visualisation. We demonstrate that the novel assay can detect A. astaci from tissue and environmental DNA with higher sensitivity than the available qPCR assay and readily distinguishes Aa from its non-pathogenic sister taxon A. fennicus. We tested two genomic marker sites for Aa that discriminate closely related oomycetes and incorporate field-deployable lateral flow and fluorescence readouts. Our work will make crayfish plague monitoring broadly accessible to practitioners and non-academic stakeholders as a tool to curb further Aa-driven loss of Europe's imperilled freshwater crustaceans and strengthen preparedness against future incursions of the pathogen in other regions.

Cas12a↗
PubMed2025

Application of engineered CRISPR/Cas12a variants with altered protospacer adjacent motif specificities for the detection of isoniazid resistance mutations in Mycobacterium tuberculosis.

UNLABELLED: Drug-resistant tuberculosis (TB) is a major global public health concern. Although isoniazid is currently considered one of the most effective first-line drugs for TB treatment, its efficacy is limited by the emergence of resistance. Therefore, it is imperative to develop new methods for detecting drug-resistant TB. In this study, we developed a nucleic acid detection system based on the clustered regularly interspaced short palindromic repeat (CRISPR) Cas12a_RR protein. The system combines recombinase polymerase amplification with an engineered CRISPR/Cas12a_RR protein to enable rapid and specific detection of the katG G944C mutation in isoniazid-resistant Mycobacterium tuberculosis (Mtb). It could detect the target DNA at concentrations as low as 1% in a mixed sample. Compared with TaqMan quantitative polymerase chain reaction and DNA sequencing, the CRISPR/Cas12a_RR system demonstrated superior detection performance in terms of sensitivity, specificity, and cost-effectiveness. Furthermore, it effectively differentiated between drug-resistant Mtb strains from wild-type Mtb strains in clinically isolated samples, with the entire detection process completed in 60 min. In conclusion, the CRISPR/Cas12a_RR detection system offers a novel, rapid, simple, sensitive, and specific approach for identifying isoniazid-resistant Mtb, with significant potential for clinical application, particularly in resource-limited settings. IMPORTANCE: This study presents a novel method for detecting isoniazid-resistant Mycobacterium tuberculosis (Mtb) using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas12a mutants, offering rapid detection, cost-effectiveness, and high specificity, and thereby providing a promising new avenue for detecting isoniazid-resistant Mtb.

Isoniazid↗
PubMed2026

Attomolar Detection of HIV-1 With Label-Free RCA-rCRISPR on Smartphone.

HIV remains a major global public health challenge, causing 42.3 million deaths since its discovery in the early 1980s. Despite progress in prevention and treatment, around 60% of people with HIV (PWH) remain undiagnosed in resource-limited regions due to the lack of inexpensive and equipment-free detection methods. Here, we developed a low-cost, robust, and label-free CRISPR-based diagnostic platform for detecting HIV viral load with minimal instrumentation. Our strategy combines rolling circle amplification (RCA) with plasmid reporter-based ratiometric CRISPR (rCRISPR) that enables the detection of HIV RNA down to single-digit aM sensitivity from PWH-derived HIV samples ex vivo. Unlike conventional RCA, which requires fragmentations of long RNA target sequences, our design harnesses the triple functions of the phi29 DNA polymerase (namely exonuclease activity, polymerization, and strand displacement), enabling the detection of the long HIV genome without pre-fragmentation. Cas12a reaction then detected RCA products by converting supercoiled ΦX174 plasmid reporters to relaxed forms. The target concentration was quantified based on the supercoil-to-relaxed plasmid ratio. Further, we constructed an all-in-one smartphone-based minigel electrophoresis device to demonstrate equipment-free HIV viral load testing. Finally, the assay has demonstrated for BRAF point mutation detection, showcasing the robustness of our strategy for broad disease diagnostic applications.

CRISPR↗
PubMed2026

CRISPR-Cas-based diagnostics for point-of-care detection of sexually transmitted infections: a laboratory development and evaluation study.

BACKGROUND: Timely, point-of-care diagnosis of sexually transmitted infections (STIs) is crucial for enabling prompt treatment and reducing transmission. We aimed to develop a portable, multiplexed, CRISPR-based assay panel for the detection of Neisseria gonorrhoeae (including the ciprofloxacin resistance marker gyrA S91F), Chlamydia trachomatis, Treponema pallidum, and herpes simplex virus (HSV). METHODS: In this laboratory development and evaluation study, we developed and optimised four multiplexed, CRISPR-based, diagnostic STI assays for point-of-care use. The complete assay panel comprised a CRISPR TP-HSV (cTP-HSV) panel for the detection of T pallidum and pan-HSV, with reflex testing to distinguish HSV-1 from HSV-2, and a CRISPR NG-CT (cNG-CT) panel for the detection of N gonorrhoeae and C trachomatis, with reflex testing to detect N gonorrhoeae using two additional genome regions and to identify the gyrA S91F mutation. Each pathogen was targeted at two independent genomic regions by isothermal amplification and CRISPR-Cas reaction using Cas12a and Cas13a, each with distinct fluorescent reporters. Analytical specificity and limits of detection (LODs) were determined, and a retrospective, masked concordance study was conducted on genomic DNA from 900 clinical samples (400 for cTP-HSV and reflex testing and 500 for cNG-CT and reflex testing), using quantitative PCR as the reference standard. The diagnostic accuracy of the test was assessed by analysis of receiver operating characteristic curves. FINDINGS: The overall sensitivity of the TP-HSV CRISPR assay was 82·5% (95% CI 74·0-88·7) for T pallidum and 94·4% (90·2-97·0) for pan-HSV; LODs were 6·2 copies per μL for T pallidum and 7·8 copies per μL for HSV. Reflex testing gave sensitivities of 97·0% (91·1-99·3) for HSV-1 and 96·0% (89·7-98·7) for HSV-2. The NG-CT CRISPR assay had an overall sensitivity of 80·0% (74·0-84·9) for N gonorrhoeae and 73·0% (65·5-79·3) for C trachomatis, with a LOD of 3·9 copies per μL for both pathogens. Reflex testing for the detection of the gyrA S91F mutation in N gonorrhoeae showed an overall sensitivity of 63·1% (55·1-70·4); however, this was dependent on sample type, with a sensitivity of 85·7% (46·7-99·5) in genital samples and 61·2% (52·8-68·9) in extragenital samples. For all pathogens, assay sensitivity was positively correlated with pathogen load. Area under the curve (AUC) values were 0·90 for T pallidum and 0·99 for pan-HSV in the TP-HSV assay, with values of 0·99 for HSV-1 and 0·97 for HSV-2 obtained in the reflex HSV-1-HSV-2 assay. For the cNG-CT assay, AUC values were 0·90 for N gonorrhoeae and 0·85 for C trachomatis, with a value of 0·72 obtained for gyrA S91F in the reflex cNG-gyrA assay. INTERPRETATION: Our multiplexed, CRISPR-based, point-of-care platform achieved performance consistent with WHO target product profiles for N gonorrhoeae and T pallidum. Proof-of-concept detection of the gyrA S91F resistance marker highlights its potential for resistance-guided therapy. Although optimisation is required before large-scale deployment, this suite offers a promising approach for rapid, decentralised, and resistance-informed STI diagnosis, particularly in resource-limited settings. FUNDING: Victorian Government Department of Health, Australian Government Department of Health, Disability and Ageing and Aged Care, and Australian Research Council.

Humans↗
PubMed2026

Ultra-sensitive profiling of CRISPR-Cas off-target effects with Tracking-seq2.

Accurate detection of off-target activity in primary human cells is crucial for ensuring the safety of gene therapies, yet existing methods often lack sufficient sensitivity. To address this limitation, we develop Tracking-seq2, an advanced technology that integrates exogenous 5' → 3' exonuclease treatment and non-homologous end joining (NHEJ) pathway inhibitors with the original Tracking-seq. Tracking-seq2 exhibits enhanced sensitivity in profiling off-target sites of diverse genome editors-including Cas9, Cas12a, cytosine base editors (CBEs), adenine base editors (ABEs), and prime editors (PEs). Critically, Tracking-seq2 is directly applicable to clinically relevant primary human cell types, such as T cells and CD34+ hematopoietic stem and progenitor cells (HSPCs). Furthermore, our findings reveal that genomic variations drive distinct off-target heterogeneity across different individuals, highlighting the necessity for personalized safety assessment in clinical genome editing applications. Tracking-seq2 provides a robust platform for sensitive off-target detection in primary cells, with sensitivity comparable to or exceeding current state-of-the-art methods.

Humans↗