Pax6Sey/Sey embryos (J). Red arrows indicate positions of the ECN and LRN and red arrowheads indicate ectopic settlement of mms neurons in Pax6Sey/Sey embryos. (Scale bar is 0.3mm in [A, A9]; 0.2 mm in [B, B9, C, C9, D, D9, F, F9, H, H9]; 0.9 mm in [E, E9]; 1 mm in [G, G9]; 1.2 mm in [I, I9]; 2 mm in [J, J9].) (TIF) Figure S3 Increased size of the Pax6Sey/Sey inferior olive. (A) Complete series of coronal E14.5 wt and Pax6Sey/Sey brainstem vibratome sections stained with Etv1 by in situ hybridization. (B) Examples of the size determination of the inferior olivary nuclei. Shown are two individual pairs of E14.5 embryos stained with Etv1 and one pair of E14.5 embryos stained with Pou4f2. Note that Etv1 is a specific marker for inferior olivary cells, whereas, Pou4f2 stains mms and inferior olivary neurons and may therefore also include mms neurons that have ectopically migrated into the inferior olivary territory. Values are given in mm2 for the area taken by the left plus right inferior olivary sub-nuclei. (C,D,E,F) In situ hybridization of coronal wt (C,D,E) and Pax6Sey/Sey (F) E14.5 (C,D) and E18.5 (E,F) vibratome sections. Fgfr2a (C) and Unc5h3 (D) label both: migrating mms neurons and IO neurons. RgmB labels equally the dorsal and principal sub-nuclei of the wt and the Pax6Sey/Sey inferior olive suggesting a normal patterning of the mutant inferior olivary nucleus. Scale bar: 0.44 mm in [A]; 0.7 mm in [C,D]; 0.55 mm in [E,F]. (TIF) Figure S4 Efficiency of shRNA and siRNA gene knockdown. (A–D) Efficiency of RNA knockdown. The fold repression was determined by the degree of silencing of Renilla luciferase- targeting construct relative to the firefly luciferase control. Averages of two to four individual experiments are shown as indicated. (E) The target sequences of shRNA constructs as References 1. van Heyningen V, Williamson KA (2002) PAX6 in sensory development. 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