Figure 1.

SCP1 as an anti-neural factor in the chick neural tube. (A) In situ hybridization on chick embryos reveals that SCP1 is widely expressed but down-regulated in the lateral neuronal zone. (B) SCP1-misexpressing cells (GFP⁺ cells) in the lateral zone lack the NF expression. (C) Misexpression of SCP1 leads to ectopic BrdU⁺-proliferating cells in the lateral zone (cells in red circle), and this is markedly enhanced by coexpression of REST. (D,E) While ectopic BrdU⁺ cells lack post-mitotic marker p27^kip1 (arrows in D), they maintain expression of progenitor gene Pax6 (arrows in E). (F,G) Phosphatase-inactive SCP1 mutant SCP1-pi induces ectopic and precocious NF⁺ neuronal differentiation (arrows in F) and expression of p27^kip1 (arrows in G) in the medial zone of the chick neural tube.