Dual-AAV delivering split prime editor system for in vivo genome editing
Zhi et al. (2022) established that prime editors — too large (~6.3 kb) to fit in single AAV vectors — can be split across two AAV particles using Rma intein-mediated protein trans-splicing. They screened split sites and identified split-PE1005 and split-PE1024 as highly active candidates. Dual-AAV1 vectors delivered these editors to human cells; dual-AAV8 vectors achieved in vivo editing of the Dnmt1 gene in adult mouse retina following subretinal injection. The retina is a post-mitotic sensory tissue — closely analogous in cell biology to the cochlea — making this the first published demonstration that split-intein dual-AAV PE works in post-mitotic sensory tissue in vivo.
Author note: This paper was cited in earlier h07 notes as “Villiger 2021” (PMID 34298129). The correct first author is Shengyao Zhi (Sun Yat-sen University). “Villiger 2021” dual-AAV split PE retina paper does not exist in PubMed. Corrected 2026-04-25.
Key finding
Dual-AAV8 + Rma intein split at PE1005 or PE1024 achieves in vivo prime editing in adult mouse retina. The scientific claim (dual-AAV split PE works in post-mitotic sensory tissue) is confirmed correct; only the attribution was wrong.
Numbers that matter
| Parameter | Value | Units | Source | Conditions |
|---|---|---|---|---|
| Target locus (in vivo) | Dnmt1 | gene | Abstract | Adult mouse retina, subretinal injection |
| Delivery vector | Dual-AAV8 | — | Abstract | Subretinal route; post-mitotic photoreceptors / RPE |
| Splicing mechanism | Rma intein trans-splicing | — | Abstract | Protein reconstitution post-transduction |
| Active split sites identified | PE1005, PE1024 | positions | Abstract | High-activity candidates from screen |
| In vitro delivery vector | Dual-AAV1 | — | Abstract | Human cell line validation |
| Edit types demonstrated | Base transversions + insertions | — | Abstract | Multiple endogenous genomic sites |
Limitations
- Editing efficiency percentage not quantified in abstract; full PMC text (PMC8753371) has the numbers.
- Dnmt1 is an endogenous mouse locus, not a therapeutic target; proof-of-concept only.
- Retina ≠ cochlea: injection route (subretinal vs round window membrane) differs; AAV8 tropism for retina may not transfer directly to OHCs (Anc80L65 preferred for cochlea).
- Epub July 2021; published January 2022 — cited year varies by source.
Connections
[source]Prime Editing for STRC — establishes dual-AAV split-intein PE in post-mitotic sensory tissue; corrected from “Villiger 2021”[source]STRC Cross-Hypothesis Verification Sweep 2026-04-25 — wrong-author correction applied this turn[part-of]prime-editing — prime-editing topic parameter table[applies]h07 hub — delivery architecture precedent for dual-AAV split PE in OHCs[see-also]2024-davis-dual-aav-split-prime-editor-brain — same split-intein architecture, neurons