Figure 7. The effects of internal insulators on the expression of the RK-GFP and IRBP156-CHER transgenes carried by the pFIN-RK-GFP-IRBP156-CHER-WPRE vector. Examination of the expression of GFP and CHER in retinas transduced with pFIN-RK-GFP-HS4(2×250)F-IRBP156-CHER-WPRE (3.3×10⁸ vector genomes/µl; A-J) or pFIN-RK-GFP-HS4(1.2)F-IRBP156-CHER (1.2×10⁸ vector genomes/µl; K-T). Each lentivirus was injected into the developing neural tubes of E2 chicken embryos in ovo. The retinal whole mounts were photographed twice using the exposure duration shown in lower left of each panel and filters appropriate for detection of GFP or CHER. The GFP and CHER images were merged (C, H, M, R) and analyzed using the co-localization module of the Zeiss AxioVision Image Suite. The results of these analyses are expressed as the percent of the transduced area in the image (pixels) containing co-localized GFP and CHER (yellow bar) or GFP (green bar) or CHER (red bar) fluorescence alone D, I, N, S. The images shown in E, J, O, T were derived from the merged images (C, H, M, R) and show only those areas of the merged image in which GFP and CHER were co-localized. The scale bar shown in A is applicable to all images and equals 50 µm.