TSPEAR S475TfsX79 mutation does not affect auditory function, tooth morphology or hair development in mice.

TSPEAR is a member of the EAR (epilepsy-associated repeat) protein family with poorly characterized function. Several lines of evidence suggest that mutations in the human TSPEAR gene are associated with hearing loss or ectodermal dysplasia. Although tooth abnormalities and a reduced capacity for caudal fin regeneration were observed in the Tspeara;Tspearb knockout zebrafish model, there have been no reports of the Tspear knockout mouse model to date, which hampers further investigation of its physiological role. Here, we inactivated the Tspear gene in mice using CRISPR/Cas9-mediated genome editing. Intriguingly, stereociliary morphology and auditory function remain unaffected in TSPEAR S475TfsX79 mutant mice. Similarly, tooth morphology and hair development are unaltered in these mutants. Nevertheless, the S475TfsX79 mutation appears to perturb both Notch and Wnt signaling pathways. Specifically, Notch1 and several downstream target genes are downregulated, whereas Heyl expression is upregulated in the skin. Additionally, Wnt4 expression is elevated in both the skin and inner ear. In conclusion, our data demonstrate that TSPEAR S475TfsX79 mutation does not compromise auditory function, tooth morphology, or hair development in mice, but TSPEAR may modulate both Notch and Wnt signaling pathways in the mouse.