Additional Supporting Information may be found in the online version of this article.

STEM_630_sm_suppinfofig1.tif5029KSupplementary Figure 1. Expression of Hoxb1 in the trunk region of the neural tube reduces mitotic rates and results in thinning of the neural tube. Immunohistochemical detection of BrdU incorporation on transverse sections of the neural tube 6h PE of Hoxb1 (A-C) and quantitation shows reduced incorporation in Hoxb1+ cells as compared to control cells (F) (p<0.001) and results in thinner neural tube on the electroporated side apparent by 24h PE (compare brackets in D, E).
STEM_630_sm_suppinfofig2.tif8312KSupplementary Figure 2. Expression of anterior Hox genes in the trunk neural tube may induce upregulation of HNK-1. Immunohistochemical detection of HNK-1 (A-I) was performed on transverse sections of neural tubes 24h PE with Hoxa1 (A-C), Hoxb2 (D-F) and Hoxb4 (G-I). Expression of Hoxa1 and Hoxb2 upregulated HNK-1 in a cell autonomous manner (A-F, asterisks in B and E) but electroporation of Hoxb4 had no effect on HNK-1 expression (G-I).
STEM_630_sm_suppinfofig3.tif9292KSupplementary Figure 3. Expression of Hoxb1 in the midbrain region induces a neuronal to neural crest switch. Immunohistochemical detection of HNK-1 (A-C), Snail2 (D-F), Msx1/2 (G-I) and Tuj1 (J-L) was performed on transverse sections of the midbrain 24h PE with Hoxb1. Expression of Hoxb1 upregulated HNK-1 (A-C, asterisks in B), Snail2 (D-F, asterisks in E) and Msx1/2 (G-I, asterisks in H) whereas it repressed expression of the neuronal marker Tuj1 (J-L, arrowheads in K).
STEM_630_sm_suppinfofig4.tif4289KSupplementary Figure 4. Expression of Hoxb1 in the trunk region represses expression of Sox9 and FoxD3. Detection of Sox9 (A-C) and FoxD3 (D-F) expression by in situ hybridisation on transverse sections of neural tubes 12h PE (A-C) and 24h PE (D-F). Ectopic expression of Hoxb1 represses expression of Sox9 12h PE (arrowheads in B) and FoxD3 24h PE (arrowhead in E).
STEM_630_sm_suppinfofig5.tif8533KSupplementary Figure 5. Blocking Wnt signalling does not affect the ability of Hoxb1 to induce NC cell fates. Immunohistochemical detection of Msx1/2 (A-C), HNK-1 (D-F), Snail2 (G-I), Pax7 (J-L) and Pax3 (M-O) on transverse sections of neural tubes 24h PE (A-O) of dnTCF4 alone (A-C) or in combination with Hoxb1 (D-O). Electroporation of dnTCF4 alone repressed Msx1/2 expression on the electroporated side (A-C, arrowheads in B). However, ectopic expression of Hoxb1 in the presence of dnTCF4 still resulted in ectopic expression of HNK-1 (D-F, asterisks in E), ectopic expression of Snail2 (G-I, asterisks in H) and repression of Pax7 (J-L, arrowheads in K) and Pax3 (M-O, arrowheads in N).
STEM_630_sm_suppinfo.doc33KSupporting Information

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