Generation of a STRAIGHT-IN Dual AAVS1 hiPSC line with orthogonal landing pads for versatile DNA payload integration.

The STRAIGHT-IN platform is designed for facile genomic integration of DNA payloads into human induced pluripotent stem cells (hiPSCs) that contain a pre-inserted landing pad (LP). Here, we expanded the versatility of STRAIGHT-IN by introducing an additional, orthogonal LP into the unmodified allele of the safe harbor locus AAVS1. Specifically, we targeted the hiPSC line LUMC0099iCTRL04_AAVS1-bxb-v2 (hPSCreg LUMCi004-A-1), which already carried one LP. The resulting STRAIGHT-IN AAVS1 Dual line can integrate two independent DNA payloads in parallel, expanding the applicability of the platform for complex genomic engineering applications.