Fig. 6. Disturbance in the AP polarity of somites and preserved expression of paraxis in rs mutants. Whole-mount in situ hybridization of rs/rs embryos (B,D,F,H,J) compared with stage-matched control embryos (A,C,E,G,I) at early E10 (A-F) and late E10 (G-J) with probes for Sox10 (A,B) Tbx18 (C,D), Uncx4.1 (E,F) and paraxis (G-J). (A-F) Sox10-positive domains show the status of segmentation of the DRGs. In rs/rs, DRG segmentation in the caudal region is disturbed (yellow arrowheads in B). Expression patterns of Tbx18 and Uncx4.1 in rs/rs in somites rostral to the hindlimb bud are fairly normal and are restricted to the anterior and posterior compartments, respectively. In more caudal regions, their expression patterns become diffuse in rs/rs. (G-J) Expression of paraxis is well maintained in rs/rs (overviews in G,H; magnified views in I,J). Both the initiation of paraxis expression in the PSM (red arrowheads in I,J) and its strong upregulation in the rostral PSM (black arrowheads in G-J) take place normally in rs/rs. FL, forelimb buds; HL, hindlimb buds.