Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1231090 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Adenine base editors (ABEs) are precise gene-editing agents that convert A:T pairs into G:C through a deoxyinosine intermediate. ABEs function most effectively when the target A is in a TA context. Deficient ABE processing of RA (R = A or G) is most evident when the target A is outside the comfortable editing window or when delivery is suboptimal. In the current study, we report directed evolution of TadA8r, a new variant of the Escherichia coli tRNA-specific adenosine deaminase (TadA) with ultra-fast deoxyadenosine deamination and no context bias.
2023-09-14 | GSE242012 | GEO
Project description:Precise adenine base editors that exhibit minimized cytosine catalysis
| PRJNA693459 | 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:In this study, we set out to reprogram deaminase context specificity to pinpoint editing. We identified multiple nucleic acid-recognition hotspots in the E. coli tRNA-specific adenosine deaminase (TadA). Strategically sampling these recognition hotspots, we first accessed multipotency for C in TadA and subsequently eliminate its A-deamination activity. We further reprogrammed TadAC context specificity through 16 evolution campaigns, each aimed at a defined NCN context, and isolated hundreds of thousands of context-specific cytosine deaminases. Our panel of 16 NCN-specific deaminases covers the full spectrum of all possible minus1 and plus 1 contexts for a target C, offering on demand deaminase choices for editor customization. Our context-specific CBEs corrected 5,866 of 7,196 disease-associated T:A-to-C:G transitions documented by ClinVar with higher accuracy than existing CBEs, often achieving selective editing of a single cytosine out of multiple cytosines in the protospacer without compromising editing potency. We also showcased the application of context-specific base editing for modeling disease-associated C:G-to-T:A transitions using two cancer driver mutations, KRASG12D and TP53R248Q, each demanding selective editing of one cytosine in two consecutive cytosines (ACC and CCG). These context-specific editors, as expected, showed tightly controlled off-target profiles by rejecting most cytosines at potential off-target sites. Bystander-free, single-nucleobase editing, as enabled by reprogramming deaminase context specificity, complements our current editor portfolio and unlocks new potential in base editing.
2025-04-14 | GSE294219 | GEO