Act I · Physical & Clinical Story
Search-and-Replace Without Cutting the Chromosome in Two
Writing directly into human chromosomes without cutting both strands of the double helix remained an unsolved challenge until recent breakthroughs in search and replace molecular engineering. Reporting in Nature Biomedical Engineering, researcher Ines Sousa and her multidisciplinary colleagues demonstrated that precision prime editing can correct the classic three nucleotide deletion in the cystic fibrosis channel gene within primary human airway cells. Standard gene scissors cut both strands of the genomic duplex, triggering unpredictable insertions and deletions that damage delicate airway tissues. Earlier single base editors could swap individual letters, yet remained powerless against deletions or complex stop signals. By pairing an engineered nicking enzyme with a specialized reverse transcriptase and an extended guide ribonucleic acid, this modular architecture copies exact genetic corrections directly into chromosomal DNA without catastrophic fragmentation. Their quantitative findings establish that systematic chemical and architectural tuning of the guide tail yields remarkable functional recovery in living human respiratory epithelia.
Every human cell carries a vast instruction manual written in chemical letters that govern life. When vital letters vanish from a gene, the cell cannot construct working chloride channels. Early gene tools acted like blunt shears. By cutting completely through both strands of DNA, older nucleases triggered chaotic cellular alarms and left unpredictable genomic scars. Prime editing operates with the gentle elegance of an electronic word processor. Instead of severing the entire chromosome, an engineered molecular machine nicks only one strand and holds open a flexible flap of DNA. A custom copying enzyme reads an included guide ribbon, writing the missing letters directly into the genome with microscopic precision. Once the new letters settle, the cell trims away the unedited flap and seals the corrected code forever. This single intervention durably restores normal channel production without breaking the underlying chromosome.
Everyday Analogy: Picture a master bookbinder repairing a torn, centuries-old parchment volume without cutting the spine. Instead of slicing through the binding cords, the binder carefully lifts a single loose paper flap along the damaged edge. She slides a narrow template ruler underneath to align the missing characters. Using an ultra-fine quill, she inscribes the missing words directly onto the newly supported paper lip. A protective brass clasp shields the delicate script from smudging while the ink sets. Once dry, the freshly lettered flap slides seamlessly over the old torn margin, and natural adhesive integrates the patch durably. The rest of the fragile manuscript remains completely untouched throughout the entire delicate operation. This analogy stops being accurate because genomic repair enzymes operate under continuous thermal Brownian agitation, where chemical flap competition and cellular mismatch repair proteins can dismantle the newly synthesized strand before it ever seals.
How the Two Sliders Work in Plain Words: Before engaging with mathematical rate equations, our interactive workbench lets you manipulate the two governing control levers of prime editing. The first control governs the Primer Binding Site (PBS) Melting Temp Match. Tuning this temperature dial optimizes how firmly the guide ribbon grips the exposed genomic strand; if the grip is too loose, reverse transcription never initiates, while an overly tight grip causes the guide to tangle into dead-end knots. The second control adjusts the epegRNA 3'-Pseudoknot Protection & MMR Evasion. Increasing this protective factor shields the guide tail against cellular degradation enzymes and prevents mismatch surveillance proteins from undoing your edit. As you adjust these levers, observe how the Clean CFTR Allele Correction Yield climbs toward thirty-five percent. Simultaneously, watch the Restored CFTR Cl⁻ Current surge past fifty percent of wild-type flux, while the Unwanted Indel Byproduct Ratio remains negligible. Finally, note the Cargo Footprint readout, which reminds us of the delivery vehicle capacity needed to transport this molecular engine.
Prime editing unites a Cas9 H840A nickase with an engineered reverse transcriptase and an engineered prime editing guide RNA (epegRNA) that carries both the address of the target site (the spacer) and the exact spelling of the corrected DNA sequence (the Reverse Transcriptase Template, RTT). When the nickase cuts just one strand of the CFTR locus, the cell's own DNA strand serves as the primer for reverse transcription—stitching the missing three nucleotides of Phe508 directly back into exon 11.
The biophysical stakes of prime editing in respiratory epithelia center on whether a non-cleaving molecular machine can achieve sufficient functional correction to restore airway surface hydration. In primary human nasal and bronchial epithelial cells carrying the common F508del mutation, Sousa and colleagues demonstrated that un-optimized prime editing yielded negligible correction due to rapid exonuclease degradation of the guide tail. However, engineering a protective structural pseudoknot onto the extension and fine-tuning primer hybridization thermodynamics elevated clean genomic editing to nearly thirty-five percent. This genomic correction translated directly into restoration of short-circuit chloride current exceeding fifty percent of normal wild-type levels in patient-derived tissues. Unlike double-strand break nucleases, prime editing generated unwanted insertion-deletion artifacts below one percent. Crucially, the large six-kilobase physical footprint of the editor complex poses a formidable barrier for delivery across thick airway mucus. Translational success hinges on engineering non-viral vehicles capable of packaging this multi-component cargo without compromising cellular viability.
“Completes Pillar II by providing a programmable, DSB-free mechanism capable of correcting all 12 possible base-to-base conversions plus targeted insertions (F508del +CTT) and multi-kilobase recombinase integrations (PASSIGE).”
— Cross-Pillar Research Thread · Grounded in Sousa et al. (2024), Nature Biomedical Engineering 9(1):7-21 — Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells (PMID 38987629).
Key Parameters, Readouts & Primary Anchor
| Quantity / Anchor | Pinned Baseline | Physical / Clinical Role |
|---|---|---|
| Primer Binding Site (PBS) Melting Temp Match | 34.0 °C T_m |
Primary perturbation axis (24.0 to 42.0 °C T_m) |
| epegRNA 3'-Pseudoknot Protection & MMR Evasion | 4.2× boost |
Coupled co-perturbation axis (1.0 to 6.0× boost) |
| Clean CFTR Allele Correction Yield & Restored CFTR Cl⁻ Current (%WT I_sc) | 34.8% (Primary Airway HNE) · 52.0% of Wild-Type Flux |
Baseline biophysical operating point |
| Primary Literature Anchor | DOI 10.1038/s41551-024-01233-3 | Sousa et al. (2024), Nature Biomedical Engineering 9(1):7-21 — Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells (PMID 38987629). · Kernel src/scripts/cftr-prime-editing.js |
Act II · From Intuition to Governing Law
Thermodynamic PBS Annealing and 3'-Flap / 5'-Flap Branch Migration
Three coupled physical equilibria govern prime editing efficiency η_PE. First, the exposed 3'-extension of a standard pegRNA is rapidly degraded by cellular exonucleases unless capped by a structured 3'-pseudoknot such as tevopreQ1 (forming an epegRNA, Nelson et al. 2022), which raises the intact intracellular guide concentration [epegRNA]_intact by 3- to 4-fold. Second, the Primer Binding Site (PBS) must hybridize to the nicked genomic strand with a melting temperature T_m near 30–36 °C: if the PBS is too short, reverse transcription fails to initiate; if it is too long, the epegRNA self-folds into an inactive hairpin. Third, once the edited 3'-DNA flap is synthesized, it competes via branch migration with the unedited 5'-DNA flap. Installing benign synonymous mutations alongside the therapeutic edit evades MLH1/MSH2 mismatch repair recognition, shifting K_flap strongly toward durable incorporation.
The biophysical efficiency of prime editing is governed by a sequence of coupled thermodynamic and kinetic equilibria. First, Cas9 H840A nickase cleaves the non-target DNA strand, exposing a single-stranded 3'-hydroxyl terminus that must hybridize to the Primer Binding Site of the engineered pegRNA. This hybridization operates under nearest-neighbor base-pairing thermodynamics: if the melting temperature T_m deviates significantly from the physiological range of 30 to 37 °C, either reverse transcription initiation stalls or the extended guide self-anneals into non-functional secondary structures. Once hybridization succeeds, the tethered reverse transcriptase extends the genomic strand, synthesizing the edited 3'-DNA flap according to the template sequence. The intact intracellular concentration of this template is dramatically enhanced by structured pseudoknots, such as tevopreQ1, which shield the 3'-extension against cytoplasmic exonucleases. The overall probability of reverse transcription completion, denoted P_RT, reflects this balance between polymerization rate and competing degradation hazards.
Following reverse transcription, the newly generated 3'-flap competes against the endogenous, unedited 5'-flap for annealing to the un-nicked complementary genomic strand. This branch migration process defines an equilibrium constant K_flap = exp(−ΔG_3'flap / RT), where ΔG_3'flap represents the net hybridization free-energy difference. Incorporating silent synonymous mutations at adjacent codons destabilizes mismatch repair recognition complexes, shifting the equilibrium toward 3'-flap annealing. Flap endonuclease FEN1 subsequently cleaves the displaced 5'-flap, allowing DNA ligase to seal the edited heteroduplex. In our primary computational kernel, implemented in src/scripts/cftr-prime-editing.js, the net prime editing yield is computed as η_PE = [epegRNA]_intact · P_RT · (K_flap / (1 + K_flap)), integrating flap partition functions with mismatch evasion probabilities to model allele conversion yields across varied airway epithelial culture conditions.
Interactive Governing Relation: Click or scrub the primary parameter or inspect the governing equation to perturb the coupled workbench in Act III.
Four-Stage Mechanistic Progression
- Stage 1 (Non-Target Strand Nicking & 3'-PBS Annealing): Cas9 H840A nickase nicks the PAM-containing DNA strand, liberating a 3'-hydroxyl DNA flap that hybridizes to the Primer Binding Site (PBS, optimal T_m ≈ 30–37 °C) at the 3'-extension of the epegRNA.
- Stage 2 (tevopreQ1 Pseudoknot Exonuclease Shield): A compact 3'-RNA pseudoknot motif (tevopreQ1) protects the exposed 3'-PBS/RTT tail of the epegRNA from cellular 3'→5' exonucleases so the full Reverse Transcriptase Template (RTT) remains intact.
- Stage 3 (M-MLV Reverse Transcription of the Edit): Engineered Moloney murine leukemia virus reverse transcriptase (PEmax / PE6) extends the genomic 3'-DNA flap directly from the RTT—writing the +CTT triplet of F508del or the GGA codon of G542X.
- Stage 4 (5'-Flap FEN1 Excision & MMR Evasion): The newly synthesized 3'-flap equilibrates with the original unedited 5'-flap; FEN1 endonuclease cleaves the 5'-flap, and silent PAM-proximal synonymous edits (or transient MLH1dn) prevent DNA mismatch repair from reverting the edit.
Act III · Interactive Visual Experiment & Plain-Language Lens
Try It Yourself: PBS Melting-Temperature & Flap-Equilibrium Lab
Tune the Primer Binding Site melting temperature (T_m) and epegRNA/MMR optimization factor to trace clean allele rewriting and restored CFTR chloride current.
Base editors can swap single letters, but they cannot replace the three missing letters in F508del or fix transversion mutations. Prime editing works like a word processor's search-and-replace: it nicks just one DNA strand and uses a built-in RNA template to copy the corrected sequence directly into the gap. When paired with a landing-pad enzyme (Bxb1 integrase in PassaGENE), the same machinery can slot in an entire multi-exon replacement cassette.
Questions to discuss with a CF care team: How are prime editing and gene-insertion approaches being developed to cover multiple CFTR mutations with a single reagent?
What this diagram leaves out: Prime editing ribonucleoproteins are large cargos (~6.3 kb) whose delivery across human airway mucus remains the primary engineering bottleneck.
Search-and-Replace Walkthrough · Mode: Pinned Evidence Storyboard · How to explore this model
- Step through the four visual chapters: Click the four mechanism chapters below (1 · Non-Target Strand Nicking… through 4 · 5'-Flap FEN1 Excision &…) to watch the schematic transition across each regime.
- Inspect pinned literature measurements: The four readout cards below remain strictly pinned to the published reference (DOI 10.1038/s41551-024-01233-3) rather than synthetic slider scaling.
- Launch the full pillar simulator: Open Open Prime Editing (PEmax / epegRNA) Workbench on /cf/cftr/ for multi-parameter continuous simulation.
Pinned Primary Evidence Mode · Click Chapters 1–4 above to animate the G.06 mechanism.
K_flap = exp(−ΔG_3'flap / RT) · η_PE = [epegRNA]_intact · P_RT · (K_flap / (1 + K_flap))
Normalized Sensitivity (Stages 1–4)
Want to test this mechanism inside the full multi-module pillar observatory? Open the coupled interactive workbench on the Pillar Hub.
Act IV · Clinical & Therapeutic Horizon
Hand-Off to Pillar III (The Delivery Bottleneck)
In primary human airway epithelial monolayers derived from patients with F508del or nonsense mutations (Sousa et al., Nat. Biomed. Eng. 2024), optimized prime editing restores CFTR-mediated chloride transport to over 50 percent of wild-type levels—matching the functional benchmark of ETI in a durable, one-time genomic edit. Even further, combining prime editing with site-specific Bxb1 integrases (PASSIGE / PassaGENE) enables insertion of entire multi-kilobase CFTR cDNA super-exons that could treat hundreds of variants with a single reagent. Yet look at the bottom readout in the workbench above: the PEmax + epegRNA machinery spans roughly 6.4 kilobases. How do we carry a 6.4-kilobase molecular machine across thick CF mucus and into airway stem cells? That is the mission of Pillar III. Grounded in Lab Discovery Catalog modules: `class1_prime_base_editing`, `prime_editing_cftr`, `prime_editing_ptc_nmd_kinetics`.
The translational landscape of prime editing expands beyond single-nucleotide point mutations to encompass complex insertions, microdeletions, and whole-exon replacements. For the cystic fibrosis community, this platform offers a singular mechanistic advantage: the capability to restore true wild-type sequence at F508del by inserting the deleted CTT triplet, while simultaneously serving as a programmable engine for transversion stop mutations such as G542X that lie outside the scope of deaminase base editors. Furthermore, by pairing prime editing with site-specific serine recombinases in architectures such as PASSIGE, engineers can install sequence-specific attachment sites within non-coding introns to integrate multi-kilobase cDNA cassettes. This modular strategy creates an avenue for mutation-agnostic correction across wide patient cohorts.
Nevertheless, translating these laboratory triumphs to clinical reality requires overcoming stringent biophysical boundaries. The entire prime editing apparatus, comprising the Cas9 nickase, engineered reverse transcriptase, and extended guide RNA, spans more than six kilobases of genetic cargo. This footprint substantially exceeds the four-point-seven kilobase packaging limit of individual adeno-associated viral capsids, necessitating divided dual-vector formulations or advanced lipid nanoparticle delivery systems. Computational verification of off-target activity remains equally vital; high-throughput sequencing assays must confirm that nickase-mediated reverse transcription does not introduce spurious insertions at homologous genomic loci. While prime editing avoids the genotoxic chromosomal translocations characteristic of double-strand break nucleases, establishing long-term expression stability and durable airway stem cell transduction remains an essential focus of ongoing research.
Primary Anchor: Sousa et al. (2024), Nature Biomedical Engineering 9(1):7-21 — Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells (PMID 38987629). (DOI 10.1038/s41551-024-01233-3 · PubMed 38987629).
Governed by biophysical kernel src/scripts/cftr-prime-editing.js and cross-checked in the Open Prime Editing (PEmax / epegRNA) Workbench on /cf/cftr/.
Resumen Científico en Español (ES-MX) · Folio G.06
Edición Prima (PEmax / epegRNA) y PassaGENE: Reescritura de F508del, 1717-1G>A y Variantes de Clase I: Cómo la nickasa Cas9 H840A fusionada con una transcriptasa inversa copia una plantilla epegRNA directamente en la hebra genómica.
Para las mutaciones que los editores de bases no pueden corregir—como insertar los tres nucleótidos CTT eliminados en F508del o revertir la transversión G542X—la Edición Prima (Prime Editing) actúa como un procesador de textos molecular que escribe la secuencia correcta directamente desde una plantilla epegRNA.
En Palabras Sencillas: Cada célula humana contiene un extenso manual de instrucciones químicas que dirige todas sus funciones biológicas. Cuando faltan letras esenciales dentro de un gen, la célula es incapaz de fabricar canales de cloruro funcionales. Las primeras herramientas de edición genética actuaban como tijeras bruscas. Al cortar por completo ambas hebras de la doble hélice, provocaban alarmas celulares y dejaban cicatrices desordenadas en el genoma. En contraste, la edición prima funciona con la sutileza de un procesador de textos digital. En lugar de partir el cromosoma, una maquinaria molecular especializada realiza una pequeña muesca en una sola hebra y levanta una solapa flexible. Un motor de copiado lee una cinta guía e inscribe las letras faltantes directamente en el sitio exacto. Una vez incorporada la corrección, la célula recorta el fragmento dañado y sella la secuencia restaurada. Este procedimiento permite restablecer la producción adecuada de canales sin comprometer la integridad estructural del cromosoma.
Analogía Cotidiana: Pensemos en un maestro encuadernador que restaura un antiguo manuscrito en pergamino sin dañar el lomo del libro. En lugar de cortar las costuras principales, levanta con sumo cuidado una solapa del borde deteriorado. Coloca una pequeña regla guía por debajo para alinear los caracteres que se habían perdido con los siglos. Con una pluma finísima, escribe las palabras faltantes directamente sobre la pestaña de papel reforzada. Un broche protector de latón resguarda la tinta húmeda mientras se seca para evitar borrones. Al secarse, la pestaña corregida se integra suavemente sobre el margen anterior, y un adhesivo natural sella el parche de forma duradera. El resto del frágil manuscrito permanece intacto durante toda la intervención. Esta analogía deja de ser exacta porque los procesos celulares operan bajo una agitación térmica constante, donde enzimas de vigilancia pueden desarmar la solapa recién sintetizada antes de que logre ligarse al cromosoma.
Guía de Controles Interactivos: Antes de analizar las ecuaciones termodinámicas, nuestro laboratorio interactivo le permite manipular los dos controles principales de la edición prima. El primer control regula el acoplamiento térmico del sitio de unión del iniciador. Modificar este dial optimiza la firmeza con la que la guía molecular se sujeta a la hebra expuesta; si la unión es débil no inicia el copiado, y si es excesivamente rígida la guía se pliega sobre sí misma. El segundo control ajusta la protección por pseudonudo y la evasión del sistema celular de reparación de desacoples. Aumentar este factor protege la cola de la guía frente a enzimas degradativas y evita que la célula revierta la corrección. Al mover estos controles, observe cómo el rendimiento de alelos corregidos alcanza cerca del treinta y cinco por ciento. Al mismo tiempo, la corriente de cloruro supera el cincuenta por ciento del flujo normal, mientras que las mutaciones accidentales se mantienen por debajo del uno por ciento. Finalmente, el indicador de tamaño de carga molecular señala el reto de empaquetar esta maquinaria en vectores de entrega.
Riesgo Biofísico y Clínico: El reto biofísico de la edición prima en el epitelio respiratorio radica en si una maquinaria molecular sin cortes de doble cadena puede alcanzar la eficiencia suficiente para restablecer la hidratación de las vías aéreas. En células epiteliales de pacientes con la mutación F508del, Sousa y su equipo demostraron que la edición convencional era ineficaz debido a la rápida degradación de la guía por exonucleasas celulares. Sin embargo, al incorporar un pseudonudo protector y optimizar la termodinámica de hibridación, la tasa de corrección genómica limpia aumentó hasta casi el treinta y cinco por ciento. Esta restauración génica se tradujo en una recuperación de la corriente de cloruro superior al cincuenta por ciento de los niveles normales en tejidos primarios. A diferencia de las nucleasas tradicionales, la edición prima generó menos del uno por ciento de inserciones o deleciones no deseadas. No obstante, el gran tamaño molecular del complejo dificulta su cruce a través del moco espeso. El éxito traslacional dependerá del desarrollo de vehículos no virales capaces de transportar esta carga sin inducir toxicidad.
Derivación Formal: La eficiencia biofísica de la edición prima está regida por una serie de equilibrios termodinámicos y cinéticos acoplados. En primer lugar, la nickasa Cas9 H840A corta la hebra de ADN no diana, exponiendo un extremo terminal hidroxilo que debe hibridar con el sitio de unión del iniciador en el ARN guía extendido. Esta hibridación obedece a la termodinámica de vecinos más cercanos: si la temperatura de fusión se desvía del rango fisiológico de 30 a 37 °C, la transcriptasa inversa no inicia la síntesis o la guía forma horquillas inactivas. Una vez que la hibridación se establece, la transcriptasa inversa extiende la solapa genómica incorporando la secuencia corregida. La concentración intracelular de la plantilla intacta se preserva mediante pseudonudos como tevopreQ1, que bloquean el ataque de exonucleasas. Tras la síntesis, la nueva solapa 3-prima compite contra la solapa 5-prima no editada por aparearse con la hebra complementaria mediante migración de ramas, proceso descrito por la constante de equilibrio K_flap = exp(−ΔG_3'flap / RT). La introducción de mutaciones sinónimas adyacentes desestabiliza el reconocimiento por el sistema de reparación de desapareamientos, desplazando el equilibrio hacia la incorporación de la hebra editada. Posteriormente, la endonucleasa FEN1 escinde la solapa desplazada y una ligasa sella la heterocadena. En nuestro núcleo de simulación en src/scripts/cftr-prime-editing.js, el rendimiento final se modela integrando estas funciones de partición con las probabilidades de evasión celular.
Frontera Traslacional: El horizonte traslacional de la edición prima abarca desde correcciones puntuales hasta inserciones complejas y reemplazos de exones completos. Para la fibrosis quística, esta tecnología ofrece la ventaja de restaurar la secuencia silvestre en F508del al reinsertar el triplete CTT faltante, permitiendo corregir también mutaciones de paro como G542X que escapan a los editores de bases tradicionales. Además, al combinarse con recombinasas específicas como en el sistema PASSIGE, es posible instalar sitios de aterrizaje en intrones para integrar casetes de ADN de varios kilobases de longitud, lo que abre una vía para tratamientos universales independientes de la variante individual. Sin embargo, la traslación clínica requiere superar barreras biofísicas considerables. El complejo de edición prima supera los seis kilobases, excediendo la capacidad de empaquetamiento de cuatro punto siete kilobases de los vectores adenoasociados individuales. Esto exige recurrir a vectores duales divididos o a nanopartículas lipídicas avanzadas. Asimismo, la verificación computacional de sitios fuera de diana es crucial para garantizar que la transcripción inversa guiada no introduzca inserciones erróneas en otras regiones del genoma. Aunque se evitan las translocaciones cromosómicas graves, lograr una expresión persistente en células madre basales sigue siendo el foco central de la investigación preclínica.
Horizonte terapéutico: Completa el Pilar II al ofrecer un mecanismo sin cortes de doble cadena capaz de realizar las 12 conversiones de bases posibles, inserciones (F508del +CTT) e integraciones de exones completos. Investigación independiente, no asesoramiento médico.
Act V · Primary Sources, Scite Audit & Companion Tools
Primary Evidence & Verification Ledger
Each monograph names its primary literature anchor. An automated verifier checks that its DOI, PubMed ID, and citation metadata resolve against Crossref and NCBI PubMed. Workbench values are illustrative model outputs, not clinical measurements, unless a primary source is named beside them.
- Primary Literature Receipt: Sousa et al. (2024), Nature Biomedical Engineering 9(1):7-21 — Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells (PMID 38987629). (DOI 10.1038/s41551-024-01233-3 · PubMed 38987629).
- Citation Context (Scite): Inspect how later literature cites 10.1038/s41551-024-01233-3 on Scite.ai ·
Crossref + Scite verified (data/folio-citations.cache.json · fetched 2026-11-08 · 70 citing · 1 supporting · 44 mentioning · 0 contrasting). - Open-Source Computational & Epistemic Engine: PySINDy Two-Compartment Stem-Cell Lineage Identification (DOI 10.21105/joss.02104 · Scite Report).
- Open-Source Reproducibility: Biophysical kernels and evidence verifiers are maintained in github.com/senseiewok/cf-research and github.com/senseiewok/cf-skills.
For builders: method, companion SKILL.md, Python verifier, and edition history (REV 1.1)
cftr-prime-editing-epeg-SKILL.md · Kernel src/scripts/cftr-prime-editing.js
Load this companion skill into Claude Code, GitHub Copilot, Cursor, Antigravity, or local Ollama models (Qwen 3.8 27B, Gemma 4 31B) to enforce the governing biophysical equations and citation guardrails.
View raw SKILL.md source
--- name: cftr-prime-editing-epeg description: AI-agnostic gene-editing skill for CFTR Prime Editing (PEmax, epegRNA tevopreQ1 pseudoknot, PBS melting temperature optimization, 3'/5' flap equilibration, and MLH1dn MMR evasion). license: CC-BY-4.0 --- # G.06 — Prime Editing (PEmax / epegRNA) & PassaGENE Rewriting ## Governing Biophysical / Mathematical Law K_flap = exp(−ΔG_3'flap / RT) · η_PE = [epegRNA]_intact · P_RT · (K_flap / (1 + K_flap)) ## Primary Evidence Receipt - **Citation:** Sousa et al. (2024), Nature Biomedical Engineering 9(1):7-21 — Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells (PMID 38987629). - **DOI:** https://doi.org/10.1038/s41551-024-01233-3 - **PubMed PMID:** https://pubmed.ncbi.nlm.nih.gov/38987629/ - **Answer Tier:** T2 · Sourced Prime Editing & Flap Equilibrium Model ## Verification Rules - Optimize Primer Binding Site (PBS) length for T_m ~ 30-37 C and cap the 3'-extension with a tevopreQ1 pseudoknot (epegRNA). - Include benign synonymous PAM/protospacer edits (or PE3b nicking) to evade MSH2/MLH1 mismatch repair reversion. - Ground primary human CF airway prime editing in Sousa et al. 2024 (DOI 10.1038/s41551-024-01233-3, PMID 38987629). ## Safety & Clinical Boundary Research synthesis and biophysical modeling only — never medical advice, clinical guidance, or a treatment promise.
REV 1.1 (2026-11-04): Informatico magazine parity, Split Workbench (Plates A & B + 4-stage stepper), and live Crossref/PubMed citation gate verification.
Verified 5-Act magazine flow, untruncated headings, and bilingual EN / ES-MX structural parity.
Audited clinical dignity boundaries, non-promise guardrails, and discovery catalog coverage.
check_folio_citations.py
Verified DOI 10.1038/s41551-024-01233-3 against Crossref and NCBI PubMed metadata.
src/scripts/cftr-prime-editing.js
Coupled governing relation K_flap = exp(−ΔG_3'flap / RT) · η_PE = [epeg to interactive Plates A & B.