Rgma/Neo1a signaling is not required for junctional polarity establishment or maintenance. A–J, Transverse sections through the hindbrain of 1 dpf (A–E, H–J) and 12 som (F, G) embryos that were untreated (A, F, H) or injected with rgma MO2-injected (B, G, I), rgma gRNA exon 2 + 3 and HF-nCas9 (rgma^ex2+3), or neo1a^δ1133-FLAG (E). Embryos were labeled with phalloidin (F-actin, A–E, syan) or anti-ZO1 (tight junctions, F–J, cyan) and counterstained with DAPI (nuclei, F–J, red). Arrows indicate the formation of ventricles. nc, Visible notochord. Scale bars, 50 μm.