a Illustration of the developmental stages and specification timing of the seven major retinal cell types: retinal ganglion cells, amacrine, horizontal, bipolar, Müller, cone, and rod photoreceptors. b Time course of Hells mRNA expression in the developing retina in wild-type mice. Levels of Hells mRNA were measured by RT-qPCR and normalized to the levels at E15.5 taken as 1 (n = 3). Mean ± SD. c Representative western blot analysis of HELLS protein levels with high and low exposure. Tubulin was used as a loading control. d Quantification of the relative HELLS protein levels on western blots were E15.5 was taken as 1 (n = 3). Mean ± SD.