Fig. 4.

NF-κB promotes RA mediated differentiation of ESCs into neuroectoderm at the expense of mesoderm. (a–c) Four days after formation of EBs, cells were treated for 4 days with RA and dissociated after 8 days of differentiation. Five days after dissociation of EBs and replating, cells were stained for SMA (a), Tuj1 (b) and Islet1 (c). Scale bar: 200 μm. (d) Quantification of immunostainings. Only GFP⁺ cells were evaluated. Data show mean ± SD of three independent experiments; >750 cells were quantified. (e) Scheme of a cross-sectioned Drosophila embryo. Nuclei within the syncytium are either with high level of nuclear Dorsal (black, ventral side), intermediate levels of nuclear Dorsal (grey) or with no nuclear dorsal (white). High levels of dorsal activate target genes Twist and Snail, necessary for mesoderm formation, whereas neuroectoderm is formed with intermediate levels of dorsal. (f) Hypothetical pathway of cell fate induction by NF-κB in mESCs. ESCs are devoid of translated NF-κB [4]. Forced expression of NF-κB resulted in the formation of mesoderm [4], whereas this study indicates that knockdown of IKK1 and IKK2 enhanced the formation of neuroectoderm. ES: Embryonic stem cells; NC: Neural crest cells; NE: Neuroepithelial cells