Fig. 4.

Comparison between the expression of glial and epithelial cell markers by immortalized Müller glia with stem cell characteristics and non-pigmented CE cells (A) RT-PCR analysis of Müller (MIO-M1 and MIO-M7) and non-pigmented CE cells (CE 6165 and CE 6213) for mRNA expression of retinal pigment epithelial (RPE) markers showed that both cell types expressed mRNA for the RPE cell markers ZO-1, RPE65, MITF-A and MERTK. However, non-pigmented CE cells showed higher expression of these markers than Müller stem cells. mRNA coding for CRALBP, a characteristic marker of Müller glia was expressed by Müller cells but not by CE cells. GAPDH primers were used as control. (B) Immunostaining of Müller and non-pigmented CE cells for markers of RPE. (i) Non-pigmented CE cells showed strong staining with a pan-cytokeratin antibody, whilst no expression of this marker was observed in Müller stem cells. (ii) A small proportion of Müller stem cells stained for RPE65 (less than 10%), whilst all CE cells stained strongly for this protein. (C) Staining for glial markers showed that Müller cells that expressed stem cell properties expressed the proteins CD44 and vimentin, whilst CE cells did not stain for these markers. (CE = Ciliary Epithelium, EGF = Epidermal Growth Factor. Scale bars represents 50 μm.)