Opn1sw, encoding the short-wavelength sensitive (S-opsin), is a gene crucial for color vision. S-opsin is one of the photopigments expressed in retinal cone photoreceptors, enabling the detection of short-wavelength (blue) light. The expression of Opn1sw is under the control of nuclear receptors like RORα, RORβ, and others, and is involved in the basic dichromatic color-vision system of mammals [2,4].

In Opn1mw-/-/Opn1sw-/-mice (lacking both M-and S-opsin), cones are viable at younger ages but degenerate rapidly. AAV-mediated expression of human L-opsin can rescue cone outer segment regeneration and cone-mediated function when injected subretinally at 2 months of age or younger, highlighting the importance of early intervention in gene therapy for related disorders such as blue cone monochromacy (BCM) [1]. In Opn1sw (Neo/Neo) mice lacking S-opsin expression, ventral cones remain viable, and their increased M-opsin expression leads to heightened sensitivity to mid-wavelength light, suggesting an interaction between S-and M-opsin expression in cones [3].

In conclusion, Opn1sw is essential for normal color vision, especially in detecting short-wavelength light. Gene knockout mouse models, such as Opn1mw-/-/Opn1sw-/-and Opn1sw (Neo/Neo) mice, have provided valuable insights into the role of Opn1sw in cone function and viability, and its implications for understanding and treating diseases like blue cone monochromacy [1,3].

References:

1. Ma, Xiajie, Sechrest, Emily R, Fajardo, Diego, Baehr, Wolfgang, Deng, Wen-Tao. 2022. Gene Therapy in Opn1mw-/-/Opn1sw-/- Mice and Implications for Blue Cone Monochromacy Patients with Deletion Mutations. In Human gene therapy, 33, 708-718. doi:10.1089/hum.2021.298. https://pubmed.ncbi.nlm.nih.gov/35272502/

2. Fujieda, Hiroki, Bremner, Rod, Mears, Alan J, Sasaki, Hiroshi. 2008. Retinoic acid receptor-related orphan receptor alpha regulates a subset of cone genes during mouse retinal development. In Journal of neurochemistry, 108, 91-101. doi:10.1111/j.1471-4159.2008.05739.x. https://pubmed.ncbi.nlm.nih.gov/19014374/

3. Daniele, Lauren L, Insinna, Christine, Chance, Rebecca, Nikonov, Sergei S, Pugh, Edward N. 2011. A mouse M-opsin monochromat: retinal cone photoreceptors have increased M-opsin expression when S-opsin is knocked out. In Vision research, 51, 447-58. doi:10.1016/j.visres.2010.12.017. https://pubmed.ncbi.nlm.nih.gov/21219924/

4. Srinivas, Maya, Ng, Lily, Liu, Hong, Jia, Li, Forrest, Douglas. 2006. Activation of the blue opsin gene in cone photoreceptor development by retinoid-related orphan receptor beta. In Molecular endocrinology (Baltimore, Md.), 20, 1728-41. doi:. https://pubmed.ncbi.nlm.nih.gov/16574740/