Fig. 4. Transcriptional analysis of ATH5-expressing single cells. Stage 22-23 (E3.5) retinal cells were transfected with an ATH5-promoter/GFP-reporter plasmid either singly or in combination with a vector expressing NGN2. They were cultured for either 24 (E4.5) or 48 hours (E5.5). Stage 26 (E5) retinal cells were transfected with the ATH5-promoter/GFP-reporter plasmid and cultured for 24 hours (E6). Individual GFP-positive cells were collected and processed for single-cell RT-PCR using the primers listed in Table S1 (see supplementary material). (A) Representative transcriptional profiles obtained with a set of 39 cells from the five groups generated by the experiment, as identified by the colour code in B. RT-PCRs of total RNA isolated from E8 retina (NRE8) were used as positive controls for each set of primers. (C) Ratios of HES1-, Neuro M-, Delta 1- and ASH1-positive cells to the total number of cells tested for expression of these genes.