Fig. 2. Temporal decrease in SP cells in the developing retina. (A-E) Hoechst dye efflux assay, carried out on cell dissociates from different stages of late retinal histogenesis, revealed a temporal decrease in the proportion of SP cells (within triangle). (F) RT-PCR analysis carried out on SP and non-SP (NSP) cells from E18 retina revealed that the former predominantly expressed transcripts corresponding to Abcg2, Nestin, Notch1, Pax6 and Sox2 whereas the latter expressed those corresponding to differentiated cell markers, i.e. rhodopsin kinase (rods), mGluR6 (bipolar cells) and Brn3b (retinal ganglion cells).