Double homozygous waltzer and Ames waltzer mice provide no evidence of retinal degeneration

摘要

Purpose: To determine whether cadherin23 and protocadherin 15 can substitute for one another in themaintenance of the retina and other tissues in the mouse. Doeshomozygosity for both v and av mutant alleles (i.e., adouble homozygous mouse) cause retinal degeneration or an obviousretinal histopathology? Methods: We generated mice homozygousfor both Cdh23v-6J and Pcdh15av-Jfballeles. The retinal phenotypes of double heterozygous and doublehomozygous mutant mice were determined by light microscopy andelectroretinography (ERG). Histology on 32 different tissues, scanningelectron microscopy of organ of Corti hair cells as well as serumbiochemical and hematological examinations were evaluated. Results: ERG waves of doubleheterozygous and double homozygous mice showed similar shape, growth ofthe amplitude with intensity, and implicit time for both rod and conepathway mediated responses. Mice homozygous for both Cdh23v-6Jand Pcdh15av-Jfb mutations showed no sign ofretinitis pigmentosa or photoreceptor degeneration but, as expected,were deaf and had disorganized hair cell sensory bundles. Conclusions: The simultaneous presenceof homozygous mutant alleles of cadherin 23 and protocadherin 15results only in deafness, not retinal degeneration or any otheradditional obvious phenotype of the major organ systems. We concludethat in the mouse cadherin 23 or protocadherin 15 appear not tocompensate for one another to maintain the retina.