Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1132788 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Current base editors use DNA deaminases, including cytidine deaminase in cytidine base editor (CBE) or adenine deaminase in adenine base editor (ABE), to facilitate transition nucleotide substitutions. Combining CBE or ABE with glycosylase enzymes can induce limited transversion mutations. Nonetheless, a critical demand remains for base editors capable of generating alternative mutation types, such as T>G corrections. In this study, we leveraged pre-trained protein language models to optimize a uracil-N-glycosylase (UNG) variant with altered specificity for thymines (eTDG). Notably, after two rounds of testing fewer than 50 top-ranking variants, more than 50% exhibited over 1.5-fold enhancement in enzymatic activities. When eTDG was fused with nCas9, it induced programmable T-to-S (G/C) substitutions and corrected db/db diabetic mutation in mice (up to 55%). Our findings not only establish orthogonal strategies for developing novel base editors, but also demonstrate the capacities of protein language models for optimizing enzymes without extensive task-specific training data.
2024-01-23 | GSE253655 | GEO
Project description:We report transcriptome wide edits comparison between split-engineered base editors and intact base editors. Our results show that, split-engineered base editors show backgound levels of unique C>U edits when compared to intact base editors.
2021-10-18 | GSE181109 | GEO
Project description:Reconstructed glycosylase base editors GBE2.0 Raw sequence reads
| PRJNA778911 | ENA
Project description:Optimization of CRISPR/Cas9-mediated genome engineering has resulted in base editors that hold promise for mutation repair and disease modeling. Here, we demonstrate the application of base editors for the generation of complex tumor models in human ASC-derived organoids. First we show Efficacy of cytosine and adenine base editors in modelingCTNNB1hot-spot mutations in hepatocyte organoids. Next, we use C>T base editors to insert nonsense mutations inPTENin endometrial organoids and demonstrate tumorigenicity even in the heterozygous state. Moreover, drug screening assays on organoids harboring eitherPTENorPTENandPIK3CAmutations reveal the mechanism underlying the initial stages of endometrial tumorigenesis. To further increase the scope of base editing we combine SpCas9 and SaCas9 for simultaneous C>T and A>G editing at individual target sites. Finally, we show that base editor multiplexing allow modeling of colorectal tumorigenesis in a single step by simultaneously transfecting sgRNAs targeting five cancer genes.
2023-07-30 | GSE236490 | GEO
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:Techniques for exclusion of exons from mature transcripts have been applied as gene therapies for treating many different diseases. Since exon skipping has been traditionally accomplished using technologies that have a transient effect, it is particularly important to develop new techniques that enable permanent exon skipping. We have recently demonstrated that this can be accomplished using cytidine base editors for permanently disabling the splice acceptor of target exons. We now demonstrate the application of adenine-deaminase base editors to disrupt the conserved adenosine within splice acceptor sites for programmable exon skipping. We also demonstrate that by altering the amino acid sequence of the linker between the adenosine deaminase domain and the Cas9 nickase or by coupling the adenine base editor with a uracil glycosylase inhibitor, the DNA editing efficiency and exon skipping rates improve significantly. Finally, we developed a split base editor architecture compatible with adeno-associated viral packaging. Collectively, these results represent significant progress towards permanent in vivo exon skipping through base editing and, ultimately, a new modality of gene therapy for the treatment of genetic diseases.
2019-09-12 | GSE120125 | 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:Recent optimization of CRISPR/Cas9-mediated genome engineering has resulted in the development of base editors that can efficiently mediate C>T and A>G transitions. Combining these genome engineering tools with human adult stem cell (ASC)-derived organoid technology holds promise for disease modeling. Here, we demonstrate the application of base editors for the generation of complex tumor models in human ASC-derived hepatocyte, endometrial and intestinal organoids. First, using conventional and evolved Cas9-variants, we show efficacy of both cytosine and adenine base editors and use them to model four hot-spot point mutations in CTNNB1 in hepatocyte organoids. Next, we apply C>T base editors in endometrial organoids to insert nonsense mutations in PTEN and demonstrate tumorigenicity even in the heterozygous state. Furthermore, we use cytosine base editors for simultaneous oncogene activation (PIK3CA) and tumor-suppressor inactivation (APC and TP53). To increase the flexibility of base editor multiplexing, we then combine SpCas9 and SaCas9 base editors for simultaneous C>T and A>G editing at individual target sites. Finally, we show the power of base editor multiplexing by modeling colorectal tumorigenesis in a single step by simultaneously transfecting sgRNA’s targeting four cancer genes.
Seven clonal organoid lines and one bulk wild-type control sample were paired-end whole-genome sequenced using the Illumina Novaseq 6000 system. We sequenced four clonal intestinal organoid lines harbouring engineered TP53 and FBXW7 mutations as well as three lines targeted for oncogenic APC/TP53/PIK3CA/SMAD4 mutations. This WGS showed, as previously reported, a genome-wide increase in C>T mutations due to C>T base editor off-target activity, which is not enriched in predicted off-target regions based on the sgRNA sequences. Furthermore, we confirmed the absence of editing-induced driver mutations and lack of off-target mutational hotspots created by the genomic engineering.
| EGAS00001006886 | EGA
Project description:A variety of base editors have been developed to achieve C-to-T editing in different genomic contexts. Here, we compare a panel of five base editors on their C-to-T editing efficiencies and product purity at commonly-editable sites, including some human pathogenic C-to-T mutations. We further profile the accessibilities of twenty base editors to all possible pathogenic mutations in silico. Finally, we build the BEable-GPS (Base Editable prediction of Global Pathogenic SNVs) database for users to select proper base editors to model or correct disease-related mutations. This in-vivo comparison and in-silico profiling catalogs the availability of base editors and their broad applications in biomedical studies.
2019-09-25 | GSE136749 | GEO