Figure 9. Zbed4 mediates transcriptional activation of several genes expressed in retina.

A. Immunocytochemical detection of endogenous Zbed4 in HEK293 cells (upper image) and in HEK293 cells stably transfected with a Zbed4 expression construct (lower image). The endogenous Zbed4 in HEK293 cells is localized mainly in the nuclei (cyan) and barely detected in the cytoplasm whereas in the HEK293 stable-transfected cells Zbed4 is seen in both, the nuclei (cyan) and cytoplasm (green). DAPI was used to stain nuclei. B. Trans-activation of promoters from genes expressed in retina by Zbed4. Stably transfected HEK 293 cells expressing Zbed4 and non-transfected HEK 293 cells were used in transient transfections with luciferase reporter constructs carrying different retinal promoters. Luciferase activity was measured in the cell lysates and normalized for each transfection system to the corresponding β-galactosidase activity for each sample. The results are expressed as fold induction by Zbed4 of the mean luciferase activity of the uninduced promoter compared to that of the Vim/luc, Rho/luc, Blue/luc, Green/luc, and α-PDE/luc reporter constructs, respectively, ± S.D. p values for each pair of Zbed4 stimulated and non-stimulated promoters are noted above the bars.