Fig. 1.

Expression of ion transport genes in the X. laevis larval skin. Whole-mount in situ hybridization on stage 26 tadpoles was used to localize transcripts encoding proteins involved in ion transport, including (A,D) two subunits of the H⁺v-ATPase, (B,E) two isoforms of carbonic anhydrase and (C) a pendrin-like anion exchanger. Note that these genes are expressed in scattered cells that are absent from the posterior and anterior areas of skin, in contrast to the pattern of ciliated cells marked by α-tubulin expression (F). A magnified view is shown in the neighboring panels.