Extended Data Fig. 3: Nodal controls basement membrane remodelling in embryos and ES cells.
From: Basement membrane remodelling regulates mouse embryogenesis

a, Representative examples of control Nodalfl/flcreERT2 embryos (n = 8 embryos) fixed and stained immediately upon recovery. In the absence of tamoxifen treatment, Nodalfl/flcreERT2 embryos have a normal basement membrane appearance, as Nodal expression is not affected. Bottom, position of AP axis and basement membrane perforation patterning. Arrowheads, AVE. b, Representative examples of control embryos (n = 20) and embryos treated with Nodal inhibitor (n = 22). Note the absence of basement membrane perforations and the appearance of accumulated fibrillar laminin in embryos treated with Nodal inhibitor (SB431542). c, Percentage of embryos with basement membrane perforations appearance in control embryos and embryos treated with Nodal inhibitor (SB431542). χ2 test; ****P < 0.0001. d, LifeAct-GFP ES cells cultured in conditions to maintain pluripotency (FC + 2i-LIF) and conditions to induce exit from pluripotency (FC − 2i-LIF) plated on Cy3–gelatin; three examples for each condition (1, 2, 3 and 1′, 2′ and 3′). The stripy appearance of gelatin is a result of the way it is plated. Three independent experiments. e, Representative example from three independent experiments of Cy3–gelatin remodelling by LifeAct-GFP ES cells upon exit from pluripotency. Arrowheads point to actin enrichment (invadopodia-like structures) colocalizing with region of remodelled ECM. f, Control and SB431542-treated ES cells plated on Cy3–gelatin and cultured in conditions to allow exit from pluripotency. Right, magnified images showing colocalization of control ES cells with Cy3–gelatin perforations. g, Quantification of results in f, showing amount of Cy3–gelatin remodelling based on the percentage of fluorescence that is absent. n = 7 regions for each condition. Two-sided unpaired Student’s t-test; ****P < 0.0001; mean ± s.e.m. Scale bars, 20 μm.