Fig. 7

Expression of pkd genes in zebrafish embryos and larvae. Lateral views of whole embryo expression of pkd genes at 24 h and 5 dpf. Rostral left, dorsal up. (A,B) pkd1 is strongly expressed in the pronephros at 24 h (arrows, A) but not at 5 dpf. By 5 dpf, pkd1 expression persists only in the putative taste receptors (white asterisks, B). (C,D) pkd1b is broadly expressed throughout the dorsal-ventral hindbrain and spinal cord, and in the caudal-most midbrain at 24 h. By 5 dpf, strong expression persists in the floor plate in the midbrain and hindbrain, whilst weaker expression persists in putative taste receptors of the pharynx (white asterisks, D). (E,F) pkd1l1 is not expressed at 24 h but is detected in the ear at 5 dpf (white dotted line, F). (G,H) pkd1l2a is expressed in cells in the ventral-most spinal cord at 24 h. This expression persists at 5 dpf, as does expression in putative taste receptors (white asterisk, H). (I,J) pkd1l2b expression is not detected at 24 h and persists only weakly in the pharyngeal cartilage at 5 dpf (white asterisk, J). (K,L) pkd2 is expressed in the pronephros (arrows, K) and perhaps very weakly in the floor plate at 24 h (arrowheads, K). By 5 dpf, pkd2 expression is restricted to the ventral region of the rostral somites and putative taste receptors (white asterisks, L). (M,N) Like pkd1l2a, pkd2l1 is also expressed in cells in the ventral-most spinal cord at 24 h. This expression also persists at 5 dpf, together with weak expression in putative taste receptors (white asterisks, N). Low level diffuse staining in the brain in (A,C,F,H,L,N) and more widely in (E,I,K) is probably background staining. These embryos were stained for longer periods in order to try and detect any weak, but specific, expression in the spinal cord. As a consequence of this, the brain, which contains large ventricles which sometimes trap RNA riboprobes, often has background staining (see Section Discussion). Scale bar (A) = 100 μm.