(A, C) Electroporation of the left (A) or right (C) DM with the control, pCAG-GFP, had no effect on the basement membrane of the coelomic epithelium (arrows). Left n = 6. Right n = 4. (B, D) Electroporation of mouse Netrin4 (pCAGEN-Ntn4) and pCAG-GFP into the left (B) or right (D) DM disrupted the basement membrane underlying the coelomic epithelium (arrows) and scattered basement membrane in the mesenchyme (asterisks). Left n = 5. Right n = 5. (E) Double DM electroporations also disrupt the coelomic epithelium (arrows) but the midline appears intact despite being contacted by Ntn4+ cells (n = 3). (F, G) Electroporation of the endoderm directly with pCAG-GFP or pCAGEN-Ntn4 does not visibly affect the basement membrane underlying the endoderm (open round pointers). Control n = 5. Ntn4 n = 8. The midline appears unaffected by any of these perturbations. Scale bars = 100 um.