Alterations in phototransduction timing, dark adaptation and GNAT1 trafficking in GNAT1-edited Xenopus laevis.

In Xenopus laevis tadpoles with nonsense mutations in all four GNAT1 alleles, GNAT1 protein is absent and the scotopic ERG is absent, confirming full knockout.

• Why it matters: GNAT1 timing and trafficking are central to rod phototransduction, yet how GNAT1 loss or specific edits alter retinal signaling and adaptation remains unclear.
• What they did: F0 CRISPR-generated GNAT1-edited animals were interbred to produce F1 genotypes, then GNAT1 levels were measured by Western blot, retinal structure by histology, and function by electroretinography (ERG).
• The result: Reduced GNAT1 expression is linked to increased A- and B-wave implicit times and greater ERG delay; Q184L-GNAT1.L mimics knockout with minimal protein loss, while the three-base-pair deletion in GNAT1.S yields dominantly diminished ERG response, defective dark adaptation, structural abnormalities, and GNAT1 accumulation at the connecting cilium.

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