Fig. 5

Fig. 5 Arhgef7b is required to localize N-cadherin and Alcama to the cell junctions. (A, E) Brightfield microscopy showed that (E) the arhgef7b mutant, bubblehead (bbh), exhibited cardiac edema (red arrow) and cranial hemorrhaging (asterisk) by 60 hpf. (B, F) Confocal projections of 60 hpf control wild-type sibling and bbh mutant phalloidin stained (F-actin) hearts revealed that bbh mutant hearts failed to undergo proper cardiac looping and displayed AV canal defects. White arrowhead points to AV canal. (C, D, G, H) Immunohistochemical staining of control and bbh mutant hearts at 60 hpf using (C, G) Alcama and (D, H) N-Cadherin antibodies, revealed mislocalization of Alcama and N-cadherin in bbh mutant AV cardiomyocytes (G, H – white arrow). At – atrium, V – ventricle. (I) bbh/arhgef7b genetically interacts with rhoua. Cardiac edema and AV canal defects were observed more frequently in bbh +/ embryos than in wild-type embryos upon increasing titrated doses of rhoua MO1. (WT+2.5, 5, 7.5, 10 ng MO1 – 0%, 21.4%, 52.7%, 88.7% cardiac phenotype and arhgef7b^+/m292+2.5, 5, 7.5, 10 ng MO1 – 15.4%, 37.5%, 78.9%, 100% cardiac phenotype).