Project description:Background The safety of CRISPR-based gene editing methods is of the utmost priority in clinical applications. Previous studies have reported that Cas9 cleavage induced frequent aneuploidy in primary human T cells, but whether cleavage-mediated editing of base editors would generate off-target structure variations remains unknown. Here, we investigated the potential off-target structural variations associated with CRISPR/Cas9, ABE and CBE editing in mouse embryos and primary human T cells by whole-genome sequencing and single-cell RNA-seq analyses. Results The results showed that both Cas9 and ABE generated off-target structural variations (SVs) in mouse embryos, while CBE induced rare SVs. In addition, off-target large deletions were detected in 32.74% of primary human T cells transfected with Cas9 and 9.17% of cells transfected with ABE. Moreover, Cas9-induced aneuploid cells activated the P53 and apoptosis pathways, whereas ABE-associated aneuploid cells significantly upregulated cell cycle-related genes and arrested in G0 phase. A percentage of 16.59% and 4.29% aneuploid cells were still observable at 3 weeks post transfection of Cas9 or ABE. These off-target phenomena in ABE were universal as observed in other cell types such as B cells and Huh7. Furthermore, the off-target SVs were significantly reduced in cells treated with high-fidelity ABE (ABE-V106W). Conclusions This study raises urgent need for minimizing the off-target SVs of CRISPR/Cas9 and ABE.
Project description:Comparing the expression profiles of the genes in response to 17b-estradiol (E2) and Agaricus blazei extract (ABE) Two-condition experiment, E2- or ABE-treated vs. control cells. 2 to 3 biological replicates, independently grown and harvested. Two to three replicates per array.
Project description:Clostridium beijerinckii is an anaerobic strain and well known for acetone-ethanol-butanol (ABE) fermentation using carbohydrates derived from cellulose or starch. During ABE fermentation, various byproducts are formed, mainly including acids (acetate, butyrate and lactate) and gas (hydrogen and carbon dioxide). recently, we found that Clostridium beijerinckii is able to produce a new product that had never been reported before and tightly regulated by pH and nitrogen source.
Project description:To alleviate the ABE-mediated cytosine editing activity, we engineered the commonly-used version of adenosine deaminase, TadA7.10. We found that the D108Q mutation also reduces cytosine deamination activity in two recently-developed versions of ABE, ABE8e and ABE8s, and has a synergistic effect with V106W, a key mutation that reduces off-target RNA editing.
Project description:A-T to G-C base editing efficiency at targeted gene sites in HEK293T cells using the dCas12f-ABE design or the Cas12f-ABE design. Found that the total A-T to G-C conversion efficiency of Circular gRNAs exhibited about two-fold increase compared with U6 gRNAs. We further analyzed the pattern for A-T to G-C conversion on the target site, and observed that the most efficient base editing occurred in a narrow window A3 (3bp downstream of the PAM) similar to U6 gRNAs. In summary, Circular gRNAs with dCas12f-ABE design could enhance A-T to G-C base editing efficiency in a narrow window.
