Enabling large-scale genome editing at repetitive elements by reducing DNA nicking
Level 5 - mechanism / opinion, no new human data
Bench research / in vitro cell culture study (design analogy for non-clinical technology)
OpenAlex W3016711432 · doi:10.1093/nar/gkaa239
What was done
Researchers tested dead-Cas9 base editor (dBE) variants designed to overcome cell death caused by double-strand and single-strand DNA breaks during high-copy genome engineering. They applied guide RNAs targeting repetitive mammalian genomic elements with copy numbers ranging from approximately 32 to 161,000 per cell across human 293T cells and human induced pluripotent stem cells (hiPSCs).
What was found
The dBE variants enabled cell survival during massive multiplex editing, achieving targeted mutations at up to approximately 13,200 loci in 293T cells and up to approximately 12,200 loci in hiPSCs. According to the abstract, this increases the number of successfully targeted repetitive sites per cell by three orders of magnitude over prior records.
Why it matters
Reducing nicking-associated DNA toxicity enables ultra-high-throughput multiplex genome editing at tens of thousands of repetitive loci in human stem and somatic cells without triggering fatal cell death pathways.
Limits
This is an in vitro bench study restricted to two cultured human cell models (293T and hiPSCs). The abstract does not report specific percentage editing efficiencies, off-target rates, comprehensive cytotoxicity metrics, or long-term karyotype stability.
Cited by
- supports Church's lab has achieved up to 24,000 edits in a single genome using enzymatic targeting methods.