Phillips, J.B., Blanco-Sanchez, B., Lentz, J.J., Tallafuss, A., Khanobdee, K., Sampath, S., Jacobs, Z.G., Han, P.F., Mishra, M., Williams, D.S., Keats, B.J., Washbourne, P., and Westerfield, M. (2011) Harmonin (Ush1c) is required in zebrafish Muller glial cells for photoreceptor synaptic development and function. Disease models & mechanisms. 4(6):786-800.
Usher syndrome is the most prevalent cause of hereditary deaf-blindness, characterized by congenital sensorineural hearing
impairment and progressive photoreceptor degeneration beginning in childhood or adolescence. Diagnosis and management of this
disease are complex, and the molecular changes underlying sensory cell impairment remain poorly understood. Here we characterize
two zebrafish models for a severe form of Usher syndrome, Usher syndrome type 1C (USH1C): one model is a mutant with a newly
identified ush1c nonsense mutation, and the other is a morpholino knockdown of ush1c. Both have defects in hearing, balance and visual function from the first week of life. Histological analyses reveal specific
defects in sensory cell structure that are consistent with these behavioral phenotypes and could implicate Müller glia in
the retinal pathology of Usher syndrome. This study shows that visual defects associated with loss of ush1c function in zebrafish can be detected from the onset of vision, and thus could be applicable to early diagnosis for USH1C