Suzanne de Bruijn

88 Chapter 2 long transcript showed a low to moderate expression in retina and other tissues, such as heart and kidney, and is predominantly expressed in brain as has been previously described. 21 Localization of KIAA1549 in mouse retina sections To confirm the presence of KIAA1549 in the retina, as well as to define its specific localization in this tissue, immunofluorescence was performed in retina sections obtained from a healthy, 2-month-old mouse. Costaining was performed with anti- Centrin, a well-defined marker for the connecting cilium within the photoreceptor cell. 22 Results showed that KIAA1549 colocalized with Centrin, and thus is located at the connecting cilium of the photoreceptor cells ( Figure 4 ). Moreover, positive staining of KIAA1549 was also observed at the outer plexiform layer of the mouse retina. This layer contains neural synapses between the photoreceptors and the bipolar and horizontal cells in the retina. DAPI Centrin KIAA1549 Overlay KIAA1549 Overlay Centrin OS CC IS A B OS CC IS ONL OPL INL OPL Figure 4. Localization of KIAA1549 in the retina of an adult mouse. Immunofluorescence analysis of KIAA1549 (red) stained on an unfixed retina section obtained from a healthy 2-month-old mouse. Costaining was performed with an antibody for Centrin (green), a connecting cilium marker of the photoreceptor. (A) Provides an overview of the retina section and was imaged using a 40x magnification. The scale bar represents 20 µm. KIAA1549 is detected at the connecting cilium photoreceptor cells and the outer plexiform layer of the mouse retina. (B) Focused image of the photoreceptor region taken using a 63x magnification. The signal of KIAA1549 at the connecting cilium shows overlap with that of Centrin. CC, connecting cilium; INL, inner nuclear layer; IPL, inner plexiform layer; IS, inner photoreceptor segment; ONL, outer nuclear layer; OPL, outer plexiform layer; OS, outer photoreceptor segment.