Abstract
Purpose :
Calcium-binding proteins (CaBPs) form a subfamily of calmodulin-like proteins that were cloned from the retina. CaBP4 and CaBP5 have been shown to be important for normal visual function. Although CaBP1 and CaBP2 have been shown to modulate various targets in vitro, the physiological roles of CaBP1 and CaBP2 in vivo has not yet been investigated. The goal of this study is to characterize the retinal morphology and function of CaBP1/caldendrin and CaBP2 knockout (KO) mice.
Methods :
CaBP2 KO mice were generated by homologous recombination in ES cells. CaBP1/caldendrin KO mice were generated previously. The absence of CaBP1/caldendrin and CaBP2 in CaBP1/caldendrin KO and CaBP2 KO mice, respectively, was investigated using RT-PCR and immunohistochemistry. The retinal morphology and visual function of six-week-old CaBP1/caldendrin KO and CaBP2 KO mice were analyzed by confocal and electron microscopy and by whole-cell patch-clamp recordings of alpha-like retinal ganglion cells.
Results :
CaBP2 KO mice were viable and did not show any apparent physiological deficits or breeding problems. No evidence of morphological retinal changes were observed in CaBP1/caldendrin KO and CaBP2 KO mice compared with wild-type mice. However, whole-cell patch clamp recordings of the light responses of alpha-like retinal ganglion cells showed that these light responses in CaBP1/caldendrin KO and CaBP2 KO mice were altered compared with those of wild-type mice.
Conclusions :
Our results show that lack of CaBP1/caldendrin or CaBP2 results in altered light responses of alpha-like retinal ganglion cells, indicating an essential role for CaBP1/caldendrin and CaBP2 for the normal transmission of light signals throughout the retinal circuitry.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.