In vivo analysis of trafficking and functional impact of hERG pore-domain missense variants in a CRISPR/Cas9-engineered C. elegans model of long QT syndrome
Abstract
Background: Loss-of-function variants in KCNH2, which encodes hERG, are responsible for long QT syndrome type 2 (LQT2), a major cause of sudden cardiac death. Most hERG pore-domain missense variants are associated with severe LQT2. However, functional heterogeneity exists among these variants, with a small subset associated with milder phenotypes. Only a limited number of these atypical variants have been functionally characterized. Caenorhabditis elegans expresses UNC-103, a voltage-gated potassium channel orthologous to hERG, with high conservation in sequence and channel biogenesis regulators, supporting its use as an in vivo model to investigate hERG variants. Objective: This study aimed to develop a C.elegans model for in vivo characterization of hERG pore-domain missense variants. Methods: Using CRISPR/Cas9 genome editing, we generated fluorescent UNC-103 knockin strains. We established an approach combining fluorescence in vivo imaging to assess channel trafficking efficiency, with behavioral readouts of muscle hyperexcitability to evaluate the integrated functional impact of hERG variants, encompassing defects in trafficking, gating, and potassium permeability. Results: The model faithfully recapitulated the profiles of G628S and G604S, 2 well-characterized hERG variants associated with severe LQT2. Moreover, it enabled in vivo characterization of G603S, a recently identified atypical pore-domain variant associated with a mild LQT2 phenotype in heterozygous carriers and a severe long QT syndrome in the homozygous state. G603S exhibited a trafficking defect responsible for a partial loss of function. Conclusion: This CRISPR/Cas9-engineered C.elegans model complements in vitro assays and complex transgenic animals, enabling in vivo characterization of hERG pore-domain missense variants.
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BibTeX
@article{deliniere2026vivo,
title = {{In vivo analysis of trafficking and functional impact of hERG pore-domain missense variants in a CRISPR/Cas9-engineered C. elegans model of long QT syndrome}},
author = {Antoine Delinière and Clément Boiteux and Clara Blancfuney and Sara Hysa and Lucía Rodríguez Martín and Sara Sechi and Elie Nevoret and Philippe Chevalier and Thomas Boulin and Olga Andrini},
journal = {Heart Rhythm},
year = {2026},
month = may,
doi = {10.1016/j.hrthm.2026.05.031},
url = {https://hal.science/hal-05772788v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - In vivo analysis of trafficking and functional impact of hERG pore-domain missense variants in a CRISPR/Cas9-engineered C. elegans model of long QT syndrome
AU - Antoine Delinière
AU - Clément Boiteux
AU - Clara Blancfuney
AU - Sara Hysa
AU - Lucía Rodríguez Martín
AU - Sara Sechi
AU - Elie Nevoret
AU - Philippe Chevalier
AU - Thomas Boulin
AU - Olga Andrini
PY - 2026
DA - 2026/05/25
JO - Heart Rhythm
DO - 10.1016/j.hrthm.2026.05.031
UR - https://hal.science/hal-05772788v1
AB - Background: Loss-of-function variants in KCNH2, which encodes hERG, are responsible for long QT syndrome type 2 (LQT2), a major cause of sudden cardiac death. Most hERG pore-domain missense variants are associated with severe LQT2. However, functional heterogeneity exists among these variants, with a small subset associated with milder phenotypes. Only a limited number of these atypical variants have been functionally characterized. Caenorhabditis elegans expresses UNC-103, a voltage-gated potassium channel orthologous to hERG, with high conservation in sequence and channel biogenesis regulators, supporting its use as an in vivo model to investigate hERG variants. Objective: This study aimed to develop a C.elegans model for in vivo characterization of hERG pore-domain missense variants. Methods: Using CRISPR/Cas9 genome editing, we generated fluorescent UNC-103 knockin strains. We established an approach combining fluorescence in vivo imaging to assess channel trafficking efficiency, with behavioral readouts of muscle hyperexcitability to evaluate the integrated functional impact of hERG variants, encompassing defects in trafficking, gating, and potassium permeability. Results: The model faithfully recapitulated the profiles of G628S and G604S, 2 well-characterized hERG variants associated with severe LQT2. Moreover, it enabled in vivo characterization of G603S, a recently identified atypical pore-domain variant associated with a mild LQT2 phenotype in heterozygous carriers and a severe long QT syndrome in the homozygous state. G603S exhibited a trafficking defect responsible for a partial loss of function. Conclusion: This CRISPR/Cas9-engineered C.elegans model complements in vitro assays and complex transgenic animals, enabling in vivo characterization of hERG pore-domain missense variants.
SN - 1547-5271
SN - 1556-3871
ER -