Altered Visual Function in Short-Wave-Sensitive 1 () Gene Knockout Japanese Medaka () Larvae.

Visual perception plays a crucial role in foraging, avoiding predators, mate selection, and communication. The regulation of color vision is largely dependent on opsin, which is the first step in the formation of the visual transduction cascade in photoreceptor cells. Short-wave-sensitive 1 () is a visual pigment that mediates short-wavelength light transduction in vertebrates. The depletion of resulted in increased M-opsin in mice. However, there is still no report on the visual function of in teleost fish. Here, we constructed the knockout medaka using CRISPR/Cas9 technology. The 6 dph (days post-hatching) medaka larvae exhibited significantly decreased food intake and total length at the first feeding stage, and the mRNA levels of orexigenic genes ( and ) were significantly upregulated after feeding. The swimming speed was significantly reduced during the period of dark-light transition stimulation in the -mutant larvae. Histological analysis showed that the thickness of the lens was reduced, whereas the thickness of the ganglion cell layer (GCL) was significantly increased in medaka larvae. Additionally, the deletion of decreased the mRNA levels of genes involved in phototransduction (, , and ). We also observed increased retinal cell apoptosis and oxidative stress in knockout medaka larvae. Collectively, these results suggest that deficiency in medaka larvae may impair visual function and cause retinal cell apoptosis, which is associated with the downregulation of photoconduction expression and oxidative stress.