PDE6B and retinitis pigmentosa 1: Interestingly, three different rodent RP models (rd1 mouse, S334ter, and P23H rats) displayed 5mC labeling in cells with lysine hypoacetylation (Figure 2), that is, with overactivated HDACs,4, 16 indicating that more than one epigenetic event may simultaneously affect degenerating photoreceptors.