Fig. 1. Ectopic expression of kreisler in the hindbrain of transgenic mice. (A) Construct for the generation of transgenic mice. An EphA4 r3/r5 enhancer in combination with a ß-globin minimal promoter (ßG) is used to drive expression of a kreisler mini gene in the hindbrain. (B-D) In situ hybridisation analysis of wild-type and transgenic embryos with a kreisler probe. (B) In wild-type E9.0 embryos, kreisler transcripts can be detected in r5/r6, in neural crest cells migrating to the third branchial arch and in the roof plate of the neural tube (arrow). (C) Dorsal view of an age-matched transgenic kreislerr3/r5 littermate showing additional kreisler expression in r3 and elevated expression levels in r5. (D) Side view of the same embryo shown in C revealing a flexure of the neural tube at the level of r3.
