Journal: bioRxiv
Article Title: S-SELeCT: A Human-Evolved Serine Integrase System for Efficient Large-Cargo Genome Integration
doi: 10.64898/2026.01.30.702954
Figure Lengend Snippet: Localization optimization ( A ) Split-GFP site A integration efficiency assay. Wildtype C31 attP was placed at both site A loci in HEK293 cells. Downstream of each attP, a splice acceptor, 3’ segment of GFP, and transcription-termination sequence were also introduced. To enable detection of site-specific integration, a donor plasmid was constructed that contains the elements needed to form a complete GFP-expression cassette: CMV promoter, 5’ GFP segment, splice donor, wildtype attB site. After co-transfection of the donor and integrase-expression plasmids, cells where site-specific integration has occurred can be identified by looking for green fluorescence. Integration can happen at one (panels i and ii) or both loci (panel iii). ( B ) WT C31-int dMad7 fusion protein expression cassette used to test impact of different gRNA on site A localization efficiency. A 5’ mCherry segment fused to a trans-splicing intein domain was co-expressed and separated from int-dMad7 via a 2A-skipping peptide. In the donor plasmid, the remaining 3’ mCherry segment fused to the complementary trans-splicing intein domain was co-expressed with the 5’ GFP segment mentioned in (A), and these two proteins were separated via 2A peptide ribosome skipping. ( C ) Results of site A localization experiments for the indicated guide RNAs and combinations, in transfected cells that express the fusion protein most strongly. Assay was performed for 72 hours in HEK293 cells that stably express the fusion protein from the H11 locus. ( D ) Expression (mCherry) and GFP gating. The rightmost mCherry gate was used to analyze the cells summarized in (C).
Article Snippet: The poly beta-amino ester transfection reagent Xfect (Takara 631318) was used for all plasmid delivery, at a 0.3 uL per 1 ug ratio.
Techniques: Sequencing, Plasmid Preparation, Construct, Expressing, Cotransfection, Fluorescence, Transfection, Stable Transfection