Fig. 1: Physical and functional interaction between ΔNp63α and GCM1.

a Expression of ΔNp63α and GCM1 in human placental trophoblasts. First-trimester and term placental sections were subjected to immunohistochemistry (IHC) and RNAscope in situ hybridization (ISH) for analysis of ΔNp63α and GCM1 expression. Boxed areas are shown at higher magnification at right. Arrowhead, asterisk, and arrow indicate trophoblasts expressing ΔNp63α, GCM1, and both factors, respectively. Schematic illustrations of the IHC images are presented. CC, cell column. CTB, cytotrophoblast. STB, syncytiotrophoblast. EVT, extravillous trophoblast. Placental sections were stained with CK7 Ab for trophoblasts and normal mouse IgG (M-IgG) and rabbit IgG (R-IgG) for negative controls in IHC or hybridized with dapB probes for negative controls in ISH. b Interaction between GCM1 and ΔNp63α, but not OVOL1. c Expression of GCM1 and ΔNp63α in human JAR, JEG3, and BeWo trophoblast cell lines. d Interaction of ΔNp63α-FLAG and endogenous GCM1 in BeWo cells stably expressing ΔNp63α-FLAG. BeWo cells were transduced with lentiviruses harboring pCDH-ΔNp63α-FLAG. After puromycin selection, the ΔNp63α-FLAG-expressing BeWo cells were subjected to coimmunoprecipitation analysis using FLAG mAb and GCM1 Ab. e Suppression of GCM1 target gene expression in ΔNp63α-FLAG-expressing BeWo cells. f, Enhancement of ΔNp63α expression in BeWo cells by GCM1 knockdown. g Suppression of trophoblast stemness gene expression in the differentiation of JEG3 cells stimulated by FSK or DB-cAMP. CTRL, control buffer. h Enhancement of trophoblast differentiation gene expression in FSK-stimulated JEG3 cells by ΔNp63α knockdown. The numbers underneath indicate the protein band intensities normalized against β-actin. Arrow and arrowhead in (c) and (f–h) denote the ΔNp63α band and a non-specific band, respectively. i, Enhancement of FSK-stimulated fusion of JEG3 cells by ΔNp63α knockdown. Scramble control and ΔNp63α-knockdown JEG3 cells treated with or without FSK were subjected to immunofluorescence microscopy with E-cadherin Ab. Syncytia are marked with asterisks. Scale bar, 20 μm. Cell fusion was quantified by fusion index. Data are presented as mean ± SD of independent experiments (n = 3 for e–i). Differences were assessed by unpaired two-tailed Student’s t-test (e–g, i) or one-way ANOVA with Tukey’s post hoc test (h). Source data are provided in the Source Data file.