Ontology highlight
ABSTRACT:
PROVIDER: PRJNA799907 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR17715790.fastq.gz | Fastqsanger.gz |
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Project description:CRISPR-based gene perturbation enables unbiased investigations of single and combinatorial genotype-to-phenotype associations. In light of efforts to map combinatorial gene dependencies at scale, choosing an efficient and robust CRISPR-associated (Cas) nuclease is of utmost importance. Even though SpCas9 and AsCas12a are widely used for single, combinatorial, and orthogonal screenings, side-by-side comparisons remain sparse. Here, we systematically compared combinatorial SpCas9, AsCas12a, and CHyMErA in hTERT-immortalized retinal pigment epithelial cells and extracted performance-critical parameters for combinatorial and orthogonal CRISPR screens. Our analyses identified SpCas9 to be superior to enhanced and optimized AsCas12a, with CHyMErA being largely inactive in the tested conditions. Since AsCas12a contains RNA processing activity, we used arrayed dual-gRNAs to improve AsCas12a and CHyMErA applications. While this negatively influenced the effect size of combinatorial AsCas12a applications, it enhanced the performance of CHyMErA. This improved performance, however, was limited to AsCas12a dual-gRNAs, as SpCas9 gRNAs remained largely inactive. To avoid the use of hybrid gRNAs for orthogonal applications, we engineered the multiplex SpCas9-enAsCas12a system (multiSPAS) that avoids RNA processing for efficient orthogonal gene editing.
2023-05-10 | GSE215175 | GEO
Project description:Prime editing is a highly versatile CRISPR-based genome editing technology with the potential to correct the vast majority of genetic defects1. However, correction of a disease phenotype in vivo in somatic tissues has not been achieved yet. Here, we establish proof-of-concept for in vivo prime editing, that resulted in rescue of a metabolic liver disease. We first develop a size-reduced prime editor (PE) lacking the RNaseH domain of the reverse transcriptase (SpCas9-PERnH), and a linker- and NLS-optimized intein-split PE construct (SpCas9-PE p.1153) for delivery by adeno-associated viruses (AAV). Systemic dual AAV-mediated delivery of this variant in neonatal mice enables installation of a transversion mutation at the Dnmt1 locus with 15% efficiency on average. Next, we targeted the disease-causing mutation in the phenylalanine hydroxylase (Pah)enu2 mouse model for phenylketonuria (PKU). Correction rates of 1.5% using the dual AAV approach could be increased to up to 14% by delivery of full-length SpCas9-PE via adenoviral vector 5 (AdV5), leading to full restoration of physiological blood phenylalanine (L-Phe) levels below 120 µmol/L. Our study demonstrates in vivo prime editing in the liver at two independent loci, emphasizing the potential of PEs for future therapeutic applications.
2021-12-29 | GSE174757 | GEO
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.
2023-04-12 | GSE228462 | GEO
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.
2023-04-12 | GSE228463 | GEO
Project description:Prime editing is a powerful means of introducing precise changes to specific locations in mammalian genomes. However, the widely varying efficiency of prime editing across target sites of interest has limited its adoption in the context of both basic research and clinical settings. Here, we set out to exhaustively characterize the impact of the cis-chromatin environment on prime editing efficiency. Utilizing a newly developed and highly sensitive method for mapping the genomic locations of a randomly integrated “sensor”, we identify specific epigenetic features that strongly correlate with the highly variable efficiency of prime editing across different genomic locations. Next, to assess the interaction of trans-acting factors with the cis-chromatin environment, we develop and apply a pooled genetic screening approach with which the impact of knocking down various DNA repair factors on prime editing efficiency can be stratified by cis-chromatin context. Finally, we demonstrate that we can dramatically modulate the efficiency of prime editing through epigenome editing, i.e. enhancing (or restricting) local chromatin accessibility in order to increase (or decrease) the efficiency of prime editing at a target site. Looking forward, we envision that the insights and tools described here will broaden the range of both basic research and therapeutic contexts in which prime editing is useful.
2023-04-12 | GSE228464 | GEO
Project description:The type V-I CRISPR-Cas system is becoming increasingly attractive for its potential utility in gene editing. However, natural nucleases often exhibit low efficiency, limiting their application. Here, we utilized structure-guided rational design and combinatorial protein engineering to optimize an uncharacterized Cas12i nuclease, Cas12i3. Accordingly, we developed Cas-SF01, a Cas12i3 variant that exhibits significantly improved gene-editing activity in mammalian cells and plants. Cas-SF01 displays comparable or superior editing performance compared to SpCas9 or recently engineered Cas12 nucleases. Further analysis of PAM recognition showed that Cas-SF01 has an expanded PAM range and effectively recognizes NTTN and noncanonical NATN and TTVN PAMs. Additionally, we identified an amino acid substitution, D876R, that markedly reduced the off-target effect while maintaining high on-target activity, leading to the development of Cas-SF01HiFi (high-fidelity Cas-SF01). Finally, we demonstrated that Cas-SF01 has robust gene-editing activity in both the monocot plant rice and dicot plant pepper. Our results suggest that Cas-SF01 can serve as a robust gene-editing platform with high efficiency and specificity for future genome editing applications across different organisms.
2023-11-05 | GSE236755 | GEO
Project description:High specificity of e\ngineered nucleases ensures precise genome editing. Couple methods were developed to identify off-target sites of CRISPR/Cas9, but hardly any high-throughput sequencing method can unequivocally determine their targeting efficiencies. Here we describe a comprehensive method, primer-extension-mediated sequencing (PEM-seq), which could sensitively detect CRISPR/Cas9 off-target sites as well as assess their editing efficiency by quantifying DNA interference events at on-target sites. Demonstrated by PEM-seq, we generated a high-fidelity Cas9 variant FeCas9 that possesses similar targeting ability as the wild-type while with extremely low off-target activities. Moreover, we provided further evidences for the broader range of xCas9 protospacer adjacent sequence. We also found the AcrIIA4 inhibitor could inhibit both on- and off-target activities of SpCas9, but it suppressed SpCas9 cleavage at the off-target loci not so efficiently as at the on-target sites. Finally, we believe PEM-seq is applicable to optimizing genome editing strategy for clinical purpose or creating animal model.
2019-04-03 | GSE116231 | GEO
Project description:The goal of these experiments were to test the on-target and target-adjacent editing efficiencies of different single-nucleobase editing systems. Previous studies have shown that tethering DNA mutating enzymes to Cas9-nickase-UGI complexes results in editing of chromosomal DNA. However, these editing events encompass undesirable target-adjacent nucleobase edits. Here, we characterize a novel approach that reduces the frequency of target-adjacent editing while maintaining a high level of on-target editing.
2020-02-23 | E-MTAB-8742 | biostudies-arrayexpress