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Reactivation of γ-globin expression through Cas9 or base editor to treat β-hemoglobinopathies.
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Quantum biological insights into CRISPR-Cas9 sgRNA efficiency from explainable-AI driven feature engineering.
CRISPR-Cas9 tools have transformed genetic manipulation capabilities in the laboratory. Empirical rules-of-thumb have been developed for only a narrow range of model organisms, and mechanistic underpinnings for sgRNA efficiency remain poorly understood. This work establishes a novel feature set and new public resource, produced with quantum chemical tensors, for interpreting and predicting sgRNA efficiency. Feature engineering for sgRNA efficiency is performed using an explainable-artificial intelligence model: iterative Random Forest (iRF). By encoding quantitative attributes of position-specific sequences for Escherichia coli sgRNAs, we identify important traits for sgRNA design in bacterial species. Additionally, we show that expanding positional encoding to quantum descriptors of base-pair, dimer, trimer, and tetramer sequences captures intricate interactions in local and neighboring nucleotides of the target DNA. These features highlight variation in CRISPR-Cas9 sgRNA dynamics between E. coli and H. sapiens genomes. These novel encodings of sgRNAs enhance our understanding of the elaborate quantum biological processes involved in CRISPR-Cas9 machinery.
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Novel human mutation and CRISPR/Cas genome-edited mice reveal the importance of C-terminal domain of MSX1 in tooth and palate development.
Several mutations, located mainly in the MSX1 homeodomain, have been identified in non-syndromic tooth agenesis predominantly affecting premolars and third molars. We identified a novel frameshift mutation of the highly conserved C-terminal domain of MSX1, known as Msx homology domain 6 (MH6), in a Japanese family with non-syndromic tooth agenesis. To investigate the importance of MH6 in tooth development, Msx1 was targeted in mice with CRISPR/Cas system. Although heterozygous MH6 disruption did not alter craniofacial development, homozygous mice exhibited agenesis of lower incisors with or without cleft palate at E16.5. In addition, agenesis of the upper third molars and the lower second and third molars were observed in 4-week-old mutant mice. Although the upper second molars were present, they were abnormally small. These results suggest that the C-terminal domain of MSX1 is important for tooth and palate development, and demonstrate that that CRISPR/Cas system can be used as a tool to assess causality of human disorders in vivo and to study the importance of conserved domains in genes.
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A ribonucleoprotein transfection strategy for CRISPR/Cas9-mediated gene editing and single cell cloning in rainbow trout cells.
BACKGROUND: The advent of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 technology marked the beginning of a new era in the field of molecular biology, allowing the efficient and precise creation of targeted mutations in the genome of every living cell. Since its discovery, different gene editing approaches based on the CRISPR/Cas9 technology have been widely established in mammalian cell lines, while limited knowledge is available on genetic manipulation in fish cell lines. In this work, we developed a strategy to CRISPR/Cas9 gene edit rainbow trout (Oncorhynchus mykiss) cell lines and to generate single cell clone-derived knock-out cell lines, focusing on the phase I biotransformation enzyme encoding gene, cyp1a1, and on the intestinal cell line, RTgutGC, as example. RESULTS: Ribonucleoprotein (RNP) complexes, consisting of the Cas9 protein and a fluorescently labeled crRNA/tracrRNA duplex targeting the cyp1a1 gene, were delivered via electroporation. A T7 endonuclease I (T7EI) assay was performed on flow cytometry enriched transfected cells in order to detect CRISPR-mediated targeted mutations in the cyp1a1 locus, revealing an overall gene editing efficiency of 39%. Sanger sequencing coupled with bioinformatic analysis led to the detection of multiple insertions and deletions of variable lengths in the cyp1a1 region directed by CRISPR/Cas9 machinery. Clonal isolation based on the use of cloning cylinders was applied, allowing to overcome the genetic heterogeneity created by the CRISPR/Cas9 gene editing. Using this method, two monoclonal CRISPR edited rainbow trout cell lines were established for the first time. Sequencing analysis of the mutant clones confirmed the disruption of the cyp1a1 gene open reading frame through the insertion of 101 or 1 base pair, respectively. CONCLUSIONS: The designed RNP-based CRISPR/Cas9 approach, starting from overcoming limitations of transfection to achieving a clonal cell line, sets the stage for exploiting permanent gene editing in rainbow trout, and potentially other fish cells, for unprecedented exploration of gene function.
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Multiplex gene-editing strategy to engineer allogeneic EGFR-targeting CAR T-cells with improved efficacy against solid tumors.
Chimeric Antigen Receptor (CAR) T cells have induced remarkable clinical responses in patients with hematological cancers. However, CAR T-cell therapies against solid tumors have not elicited similar outcomes since immunosuppressive barriers in the tumor microenvironment attenuate anti-tumor activity. Here, we describe a multifaceted approach to engineer allogeneic CAR T-cells resistant to both biochemical (hypoxia-adenosinergic) and immunological (PD-L1 and TGF-β) inhibitory signaling using an adenine base editor and a CRISPR-Cas12b nuclease. The resulting EGFR-targeting CAR T-cell product comprised a combination of six gene edits designed to evade allorejection (B2M, CIITA), prevent graft-versus-host disease (CD3E) and overcome biochemical (ADORA2A) and immunological (PDCD1, TGFBR2) barriers in solid tumor microenvironment of subcutaneously grown EGFR+ human lung tumor xenografts. This combinatorial genetic disruption enhances CAR T cell effector function and anti-tumor efficacy leading to improved tumor elimination and survival in xenograft and humanized mouse solid tumor models. Our strategy confers CAR T cells resistance to multiple clinically relevant inhibitory signaling pathways that are amplified in hypoxic tumor areas and may improve the therapeutic potential of CAR T-cells against solid tumors.
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CRISPR/Cas12a-based biosensing platform for the on-site detection of single-base mutants in gene-edited rice.
At present, with the accelerated development of the global biotechnology industry, novel transgenic technologies represented by gene editing are developing rapidly. A large number of gene-edited products featuring one or a few base indels have been commercialized. These have led to great challenges in the use of traditional nucleic acid detection technology and in safety regulation for genetically modified organisms (GMOs). In this study, we developed a portable clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins 12a-based (CRISPR/Cas12a-based) biosensing platform named Cas12aFVD (fast visual detection) that can be coupled with recombinase polymerase amplification (RPA) for on-site detection of mutants in gene-edited rice in one tube. The detection procedure can be accomplished in 40 min with a visible result, which can be observed by the naked eye under blue light (470-490 nm). By accurate recognition of targets based on Cas12a/CRISPR RNA (crRNA), Cas12aFVD exhibits excellent performance for the detection of two- and three-base deletions, one-base substitution, and one-base insertion mutants with a limit of detection (LOD) of 12 copies/μl showing great potential for mutant detection, especially single-base mutants. The Cas12aFVD biosensing platform is independent of laboratory conditions, making it a promising and pioneering platform for the detection of gene-edited products.
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As CRISPR Technologies Ripen, What Should We Prioritize?
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How CRISPR gene editing could help treat Alzheimer's.
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Mycobacterium tuberculosis type III-A CRISPR/Cas system crRNA and its maturation have atypical features.
Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) systems are prokaryotic adaptive immune systems against invading nucleic acids. CRISPR locus variability has been exploited in evolutionary and epidemiological studies of Mycobacterium tuberculosis, the causative agent of tuberculosis, for over 20 yr, yet the biological function of this type III-A system is largely unexplored. Here, using cell biology and biochemical, mutagenic, and RNA-seq approaches, we show it is active in invader defense and has features atypical of type III-A systems: mature CRISPR RNA (crRNA) in its crRNA-CRISPR/Cas protein complex are of uniform length (∼71 nt) and appear not to be subject to 3'-end processing after Cas6 cleavage of repeat RNA 8 nt from its 3' end. crRNAs generated resemble mature crRNA in type I systems, having both 5' (8 nt) and 3' (28 nt) repeat tags. Cas6 cleavage of repeat RNA is ion dependent, and accurate cleavage depends on the presence of a 3' hairpin in the repeat RNA and the sequence of its stem base nucleotides. This study unveils further diversity among CRISPR/Cas systems and provides insight into the crRNA recognition mechanism in M. tuberculosis, providing a foundation for investigating the potential of a type III-A-based genome editing system.-Wei, W., Zhang, S., Fleming, J., Chen, Y., Li, Z., Fan, S., Liu, Y., Wang, W., Wang, T., Liu, Y., Ren, B., Wang, M., Jiao, J., Chen, Y., Zhou, Y., Zhou, Y., Gu, S., Zhang, X., Wan, L., Chen, T., Zhou, L., Chen, Y., Zhang, X.-E., Li, C., Zhang, H., Bi, L. Mycobacterium tuberculosis type III-A CRISPR/Cas system crRNA and its maturation have atypical features.
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Scalable biological signal recording in mammalian cells using Cas12a base editors.
Biological signal recording enables the study of molecular inputs experienced throughout cellular history. However, current methods are limited in their ability to scale up beyond a single signal in mammalian contexts. Here, we develop an approach using a hyper-efficient dCas12a base editor for multi-signal parallel recording in human cells. We link signals of interest to expression of guide RNAs to catalyze specific nucleotide conversions as a permanent record, enabled by Cas12's guide-processing abilities. We show this approach is plug-and-play with diverse biologically relevant inputs and extend it for more sophisticated applications, including recording of time-delimited events and history of chimeric antigen receptor T cells' antigen exposure. We also demonstrate efficient recording of up to four signals in parallel on an endogenous safe-harbor locus. This work provides a versatile platform for scalable recording of signals of interest for a variety of biological applications.
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