Transient in vivo base editing with no detectable RNA- and DNA off-target mutations
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA623983 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR11514400_1.fastq.gz | Fastqsanger.gz | |||
| SRR11514400_2.fastq.gz | Fastqsanger.gz | |||
| SRR11514401_1.fastq.gz | Fastqsanger.gz | |||
| SRR11514401_2.fastq.gz | Fastqsanger.gz | |||
| SRR11514402_1.fastq.gz | Fastqsanger.gz |
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Project description:RNA-programmable deaminases, known as base editors (BEs), enable precise single base conversions on genomic DNA and hold great promise for therapeutic application in patients. Recent studies, however, have raised serious concern with regard to off-target effects, questioning translatability of BEs to the clinic. Here we analyze transcriptome- and genome-wide off-target effects following AAV-mediated delivery of cytosine base editors (CBEs) in vivo in an unbiased manner. We show that low expression of CBEs allows sufficient on-target editing to cure a disease phenotype with no increase in off-target effects compared to untreated controls. To further improve safety of in vivo base editing, we developed a lipid nanoparticle (LNP)-mediated delivery system to transiently express BEs. We reach up to 21% on-target editing with no detectable transcriptome- or genome-wide off-target effects, and are able to reverse the disease phenotype of a phenylketonuria mouse model. These results have important implications, underlining the feasibility of transient in vivo base editing for therapeutic use in patients.
2020-08-24 | GSE148349 | GEO
Project description:Transient in vivo base editing with no detectable DNA off-target mutations
| PRJEB40008 | ENA
Project description:We examined the off-targets of new base editing tools at RNA level
2020-10-14 | GSE142840 | GEO
Project description:CRISPR-Cas base editors are preferred tool for genome editing as they generate desired editing without any double strand break in the genome, as double stand break is detrimental to the cells. In our study we have demonstrated the significance of base editors in editing the highly homologous HBG promoter (HBG1 and HBG2) region to introduce novel HPFH-like mutation to elevate HbF for therapeutical applications. Previous studies revealed that the base editors can cause unintended Cas-independent edits at transcriptome level. To validate off-target at RNA level, we performed a transcriptome wide analysis. The frequency of unintended edits in the HUDEP-2 stable cell lines expressing the base editors with the gRNA were not significant compared to the control. We determined the ABE mediated A to I conversion and CBE mediated C to U conversion across the base edited samples. The RNA off-target analysis was carried out with the help of REDItools v 2 tool. This data suggests that despite high on-target editing in DNA, the Cas-independent RNA off-target were not at detectable range compared to control. The differential expression of 34 selected genes which necessitate globin regulation were compared between the unedited HUDEP WT, CBE control, ABE control, and edited ABE (with gRNA 2/11) and edited CBE (with gRNA 2/11). We observed that there is no significant differential gene expression between the edited and control cells except the gamma and delta globin genes. These results suggest that base editors are preferred tools to edit highly homologous HBG promoter region to created HPFH-like mutations inducing HbF levels without causing double strand breaks, larger deletions and no significant RNA off-targets which are detrimental to the gene edited cells.
2022-01-02 | GSE192801 | GEO
Project description:CRISPR technology has demonstrated broad utility for controlling target gene expression. However, there remains a need for strategies capable of modulating expression via the precise editing of non-coding regulatory elements. Here we demonstrate that CRISPR base editors, a class of gene-modifying proteins capable of inducing single-base substitutions in DNA, can be harnessed to perturb target gene expression via the targeted mutagenesis of cis-acting sequences. Using the promoter region of the human huntingtin (HTT) gene as an initial target, we show that editing of the binding site for the transcription factor NF-κB led to a marked reduction in HTT gene expression. We find that these gene perturbations were persistent and specific, as a transcriptome-wide RNA-seq analysis revealed virtually no off-target effects. We further show that this base-editing platform could lower HTT in vivo, as its delivery to a mouse model of Huntington’s disease decreased HTT expression in striatal neurons, an outcome that we show also increased survival. Finally, we use this approach to target the amyloid-beta precursor protein, demonstrating that multiplexed editing of its promoter region could significantly perturb its expression, supporting the applicability of this method. These findings thus demonstrate the potential for base editors to regulate target gene expression.
2022-08-24 | GSE204833 | GEO
Project description:Efficient CRISPR-mediated base editing in Agrobacterium spp.
| PRJEB38304 | ENA
Project description:RNA base editing applies endogenous or engineered adenosine deaminases to introduce adenosine-to-inosine changes into a target RNA in a highly programmable manner. Recently, notable success was achieved for the repair of disease-causing guanosine-to-adenosine mutations by means of RNA base editing. Here, we propose that RNA base editing could be broadly applied to perturb protein function by removal of regulatory sites of post-translational modification (PTM), like phosphorylation and/or acetylation sites. We demonstrate the feasibility of PTM interference (PTMi) on more than 70 PTM sites in various signaling proteins and identify key determinants for high editing efficiency and potent down-stream effects. Specifically, we demonstrate both negative and positive regulation of the JAK/STAT pathway by PTMi. To identify potent regulatory sites for PTMi, we applied an improved version of the SNAP-ADAR tool, which achieved high editing efficiency over a broad codon scope with tight control of bystander editing. The transient nature of RNA base editing enables the fast, dose-dependent (thus partial) and reversible manipulation of PTM sites, which is a key advantage over DNA editing approaches, where genetic compensation or lethality can conceal a phenotype. In summary, PTM interference might become a valuable field of application of RNA base editing in basic biology and medicine.
2024-04-19 | GSE264114 | GEO
Project description:Conjugation of CRISPR-Cas9 with cytidine deaminases leads to base editors (BEs) for programmable C-to-T editing, which holds potentials in clinical applications, but suffers from off-target (OT) mutations. By taking advantage of a cleavable deoxycytidine deaminase inhibitor (dCDI) domain, a transformer BE (tBE) system is developed to induce efficient editing with only background levels of genome-wide and transcriptome-wide OT mutations. After being produced, tBE remains inactive at OT sites with the fusion of a cleavable dCDI, thus eliminating unintended mutations. Only when binding at on-target sites, tBE is transformed to cleave off the dCDI domain and catalyzes targeted deamination for precise base changes. After delivery into mice via a dual-AAV system, tBE created a premature stop codon in Pcsk9 and significantly reduced serum PCSK9 level, which resulted in ~30-40% decrease of total cholesterol. Together, the development of tBE establishes a highly-precise base editing system and its in vivo efficacy envisions potential therapeutic applications.
2021-03-12 | GSE164477 | GEO
Project description:CRISPR-Cas base editor technology enables targeted nucleotide alterations and is being rapidly deployed for research and potential therapeutic applications. The most widely used base editors induce DNA cytosine (C) deamination with rat APOBEC1 (rAPOBEC1) enzyme, which is targeted by a linked Cas protein-guide RNA (gRNA) complex. Previous studies of cytosine base editor (CBE) specificity have identified off-target DNA edits in human cells. Here we show that a CBE with rAPOBEC1 can cause extensive transcriptome-wide RNA cytosine deamination in human cells, inducing tens of thousands of C-to-uracil (U) edits with frequencies ranging from 0.07% to 100% in 38% - 58% of expressed genes. CBE-induced RNA edits occur in both protein-coding and non-protein-coding sequences and generate missense, nonsense, splice site, 5’ UTR, and 3’ UTR mutations. We engineered two CBE variants bearing rAPOBEC1 mutations that substantially decrease the numbers of RNA edits (reductions of >390-fold and >3,800-fold) in human cells. These variants also showed more precise on-target DNA editing and, with the majority of gRNAs tested, editing efficiencies comparable to those observed with wild-type CBE. Finally, we show that recently described adenine base editors (ABEs) can also induce transcriptome-wide RNA edits. These results have important implications for the research and therapeutic uses of base editors, illustrate the feasibility of engineering improved variants with reduced RNA editing activities, and suggest the need to more fully define and characterize the RNA off-target effects of deaminase enzymes in base editor platforms. This SuperSeries is composed of the SubSeries listed below.
2019-03-31 | GSE121668 | GEO
Project description:C-to-T base editing mediated by CRISPR/Cas9 base editors (BEs) needs a G/C-rich PAM and the editing fidelity is compromised by unwanted indels and non-C-to-T substitutions. We developed CRISPR/Cpf1-based BEs to recognize a T-rich PAM and induce efficient C-to-T editing with few indels and/or non-C-to-T substitutions. The requirement of editing fidelity in therapeutic-related trials necessitates the development of CRISPR/Cpf1-based BEs, which also facilitates base editing in A/T-rich regions.
2018-10-16 | GSE105002 | GEO