Effect of RNAi knockdown of PI4K on photoreceptor ultrastructure. (A and B) TEM analysis showing poorly formed and fragmented rhabdomeres (r). The cell bodies of these photoreceptors show the accumulation of membrane transport intermediates (m). (C) Rh1 protein levels are reduced after RNAi-mediated knockdown of this gene. A loading control band is shown. Unit of measure, M _r.