Fig. 1

Expression of pax2.1 in the inner ear of wildtype and dlA^dx2/dx2 embryos. (A-C) Dorsolateral view of the otic vesicle at 24 h showing accumulation of pax2.1 transcripts in a wild-type embryo (A), a moderately affected dlA^dx2/dx2 mutant (B) and a severely affected dlA^dx2/dx2 mutant (C). Cells lining the medial wall of the otic vesicle are heavily labeled, including small groups of cells in the developing sensory patches (arrows). In the dlA^dx2/dx2 mutants, increased numbers of labeled cells are evident in the sensory epithelia. (D,E) Dorsolateral view of the otic vesicle at 24 h showing immunofluorescent staining with two antibodies: one directed against acetylated tubulin and the other generated against mouse Pax2. Within the otic vesicle, anti-acetylated tubulin specifically labels the apical surfaces and kinocilia of hair cells (Haddon and Lewis, 1996; Riley et al., 1997). In both wild-type (D) and dlA^dx2/dx2 (E) embryos, hair cell nuclei show strong anti-Pax2 staining (arrows), and hair cells are overproduced in the dlA^dx2/dx2 mutant. (F,G) Lateral view of the nascent otic vesicle at 18.5 h showing immunofluorescent staining with anti-Pax2 antibody in a wild-type embryo (F) and a noi^tb21/tb21 (pax2.1) mutant (G). (H,I) Lateral view of the posterior trunk and tail region showing immunofluorescent staining with anti-Pax2. Nuclei are labeled in the developing pronephros (p) and in a subset of neurons in the spinal cord (sc). (J) Dorsolateral view of anterior hair cells in a noi^tb21/tb21 mutant at 24 h labeled with antibodies directed against acetylated tubulin and Pax2. Hair cell apices and kinocilia are strongly labeled with anti-acetylated tubulin (arrow), but nuclear Pax2 staining is no longer detectable. Because noi^tb21 reduces expression of pax2.1 (Brand et al., 1996) but not pax2.2 (Pfeffer et al., 1998), these data suggest that the Pax2 antibody used here preferentially recognizes pax2.1. (A-G,J) Anterior is to the left and dorsal is upward. (H,I) Anterior is to the right and dorsal is downward. Scale bar, 10 μm (J), 20 μm (D,E), 35 μm (A-C), 60 μm (F,G), and 115 μm (H,I).