Prime editing for functional repair in patient-derived disease models
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ABSTRACT:
PROVIDER: EGAS00001004611 | EGA |
REPOSITORIES: EGA
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Project description:Prime editing is a versatile genome-editing technique that shows great promise for the generation and repair of patient mutations. However, some genomic sites are difficult to edit and optimal design of prime-editing tools remains elusive. Here we present a fluorescent prime editing and enrichment reporter (fluoPEER), which can be tailored to any genomic target site. This system rapidly and faithfully ranks the efficiency of prime edit guide RNAs (pegRNAs) combined with any prime editor variant. We apply fluoPEER to instruct correction of pathogenic variants in patient cells and find that plasmid-editing enriches for genomic editing up to 3-fold compared to conventional enrichment strategies. DNA repair and cell cycle-related genes are enriched in the transcriptome of edited cells. Stalling cells in the G1/S boundary increases prime editing efficiency up to 30%. Together, our results show that fluoPEER can be employed for rapid and efficient correction of patient cells, selection of gene-edited cells, and elucidation of cellular mechanisms needed for successful prime editing.
2022-02-03 | GSE195977 | 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 allows precise modification of genomes. To identify cellular determinants of prime editing, we developed scalable prime editing reporters and performed genome-scale CRISPR-interference screens. From these screens, a single factor emerged as the strongest mediator of prime editing: the small RNA-binding exonuclease protection factor La (SSB). Further investigation revealed that La promotes prime editing across approaches (PE2, PE3, PE4, PE5), edit types (substitutions, insertions, deletions), guide RNA designs (pegRNAs, epegRNAs), endogenous loci, and cell types, but has no consistent effect on genome editing approaches that rely on standard, unextended guide RNAs. La binds polyuridine tracts at the 3' ends of RNA polymerase III transcripts and protects those transcripts from cellular exonucleases. We found that La stabilizes (e)pegRNAs, with particular effect on their 3' extensions, where edits are encoded. Guided by these insights, we developed a prime editing protein (PE7) fused to the RNA-binding, N-terminal domain of La. This editor improved prime editing with expressed (e)pegRNAs and synthetic pegRNAs optimized for La binding. Our results provide key insights into how prime editing components interact with the cellular environment and suggest general strategies for stabilizing exogenous small RNAs therein.
2024-02-04 | GSE255003 | GEO
Project description:Prime editing enables the precise modification of genomes through reverse transcription of template sequences appended to the 3′ ends of CRISPR–Cas guide RNAs. To identify cellular determinants of prime editing, we developed scalable prime editing reporters and performed genome-scale CRISPR-interference screens. From these screens, a single factor emerged as the strongest mediator of prime editing: the small RNA-binding exonuclease protection factor La. Further investigation revealed that La promotes prime editing across approaches (PE2, PE3, PE4 and PE5), edit types (substitutions, insertions and deletions), endogenous loci and cell types but has no consistent effect on genome-editing approaches that rely on standard, unextended guide RNAs. Previous work has shown that La binds polyuridine tracts at the 3′ ends of RNA polymerase III transcripts. We found that La functionally interacts with the 3′ ends of polyuridylated prime editing guide RNAs (pegRNAs). Guided by these results, we developed a prime editor protein (PE7) fused to the RNA-binding, N-terminal domain of La. This editor improved prime editing with expressed pegRNAs and engineered pegRNAs (epegRNAs), as well as with synthetic pegRNAs optimized for La binding. Together, our results provide key insights into how prime editing components interact with the cellular environment and suggest general strategies for stabilizing exogenous small RNAs therein.
2024-01-22 | GSE253424 | 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:A truncated reverse transcriptase enhances prime editing by split AAV vectors
| PRJNA846287 | ENA
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:We evaluate CRISPR-based prime editing for application in organoids. First we model mutations in TP53 in intestinal and hepatocyte oganoids and determine the efficiency and accuracy of mutation induction on multiple targets. Then, to evaluate potential clinical applicability of prime editing we repair mutations in the CFTR channel that cause cystic fibrosis in intestinal organoids. First we repair the CFTR-F508del mutation which is the most common mutation in cystic fibrosis. Then we compare adenine base editing to prime editing by repairing the CFTR-R785* mutation using both strategies.
| EGAS00001005358 | EGA
Project description:To investigate if the truncated PE can be dilivered by dual AAV8 vectors for in vivo prime editing. We injected the dual AAV8 into 10-week-old C57BL/6J mice . Livers were isolated 4 weeks after injection and next generation sequencing showed an average of 1.4% and 5.4% precise prime editing with the low and high AAV doses, respectively (Figure 4D ). This demonstrates that PECO-Mini can be efficiently delivered by dual AAVs for in vivo prime editing.
2022-06-09 | GSE205532 | GEO