Figure 2.

Localization of RPGR in the connecting cilium by immunofluorescence. (a) Confocal image of a normal retina probed with the RPGR antibodies. A band of punctate staining is seen between the inner and outer segments, indicative of connecting cilia. (×500.) (b) Developmental time course of RPGR staining in the mouse retina. Staining first appears around postnatal day 3 as a band at the apex of the photoreceptor layer and increases in intensity and definition through day 9. (c) The connecting cilium staining for RPGR is absent in KO mice. (×250.) (d) RPGR is also localized in the connecting cilia of cone photoreceptors. Shown is RPGR immunostaining of the cone-dominant ground squirrel retina (Upper). Western blotting of ground squirrel tissue homogenates confirms that the RPGR antibodies made against mouse sequence cross-reacts with squirrel RPGR (Lower). RPE, retinal pigment epithelium; OS, outer segment; IS, inner segment; ONL, outer (photoreceptor) nuclear layer.