Fig. 5. Co-expression of RGC-specific genes and bHLH transcription factors in newborn RGCs and RGC precursors. Cells were transfected with an ATH5-promoter/GFP-reporter plasmid at stage 26 (E5) and cultured for 24 hours. (A, right) Transcriptional profile of a newborn RGC. This neuron-like GFP-positive cell (left) expresses ATH5, Neuro M, ß3 and BRN3C, but not ASH1. (B) ATH5-expressing cells do not always co-express Neuro M, ß3 and BRN3C. (C) Colocalization of ß3 promoter activity and HES1 or Neuro M expression. Cells were transfected with a ß3-promoter/lacZ-reporter plasmid at stage 24. After 24 hours in culture, lacZ-expression was revealed and cells were processed for in situ hybridization with (a) HES1- or (b,c) Neuro M-specific riboprobes. Arrowhead in a indicates a double-labelled cell.