Sox10-dependent enhancer activation is stimulated by Nfatc2 and inhibited by Olig2 and Nkx2.2. a Transient transfections of N2a cells with luciferase reporters carrying Nkx2.2 ECR19 in the absence (−) or presence (+) of Sox10 and constitutively active Nfatc2 as effectors (n = 3). Activation of reporter gene expression was determined in extracts 48 h post transfection and is presented as fold inductions ± SEM with transfections in the absence of effectors arbitrarily set to 1 (58.5 ± 4.0 for Sox10, 0.3 ± 0.0 for Nfatc2, and 130.5 ± 11.6 for Sox10 in combination with Nfatc2). b, c Neural tube electroporations in HH11-stage chicken embryos (n = 3). The relative number of electroporated cells, in which Nkx2.2 expression was induced 48 h after neural tube electroporation of Sox10 and Nfatc2, was quantified (b: 0 for control, 19.5 ± 4.9 for Sox10, 25.9 ± 4.1 for Nfatc2, and 39.0 ± 4.6 for Sox10 in combination with Nfatc2). Transverse sections were used for quantifications (c). Sections were probed for the occurrence of Nkx2.2 (white in upper row, red in lower row). Electroporated cells on the left side all express GFP (green) and to variable extent Nkx2.2 (white in upper row, red in lower row). Nuclei are counterstained by DAPI (blue). Scale bar, 50 µm. d, e Transient transfections of N2a cells with luciferase reporters carrying ECR19 (d) or OLEa (e) in the absence of added transcription factors (−) or in the presence (+) of Sox10, Olig2, Nkx2.2, and combinations thereof (n = 3). Activation of reporter gene expression was determined in extracts 48 h post transfection and is presented as fold inductions ± SEM with transfections in the absence of added transcription factors being arbitrarily set to 1 (ECR19: 55.3 ± 7.7 in the presence of Sox10, 0.7 ± 0.1 in the presence of Olig2 and 13.1 ± 2.0 in the presence of Sox10 and Olig2; OLEa: 21.6 ± 1.3 in the presence of Sox10, 2.2 ± 0.1 in the presence of Nkx2.2 and 8.8 ± 1.2 in the presence of Sox10 and Nkx2.2). Statistical significance was determined by two-tailed Student’s t-test (*P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001)