Fig. 9. Hindbrain reeler-like phenotype for scrambler mutant but no hindbrain phenotype for Reln receptors mutants. (A) At E15.5, islet 1 labels trigeminal motor, OC/FVM and facial motoneurons in control mice. (B,C) Islet 1-labeled OC/FVM cells are absent at the pial surface in reeler (B) and scrambler (C) mice. Abnormal organization of the VII nucleus is seen in reeler and scrambler mutants (lower circle). In double mutants for Reln receptors, ApoER2 and VLDLR, the Isl1 expression pattern is similar to that in control embryos, in particular, the OC/FVM group of cells can be identified at the pial surface (upper circle, D). (E-G) Expression patterns of Dab1, ApoER2 and VLDLR were examined at E12.5 in consecutive vibratome sections through r5 using ISH. Dab1 expression is observed in facial precursors close to the ventricular region (E). ApoER2 was strongly expressed within the neural tube (F); however, VLDLR was only faintly expressed (G). No specific localization in relation to the OC/FVM and facial precursor positions was observed.