Myosin Vb is required for correct trafficking of N-cadherin and cardiac chamber ballooning.

Background: During heart morphogenesis, the cardiac chambers undergo ballooning: a process involving regionalized elongation of cardiomyocytes. Cardiomyocyte shape changes require reorganization of the actin cytoskeleton; however, the genetic regulation of this process is not well understood.

Results: From a forward genetic screen, we identified the zebrafish uq mutant which manifests chamber ballooning defects.

Nppa and Nppb act redundantly during zebrafish cardiac development to confine AVC marker expression and reduce cardiac jelly volume.

Atrial natriuretic peptide () and brain natriuretic peptide () form a gene cluster with expression in the chambers of the developing heart. Despite restricted expression, a function in cardiac development has not been demonstrated by mutant analysis. This is attributed to functional redundancy; however, their genomic location has impeded formal analysis.

carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (cad) regulates Notch signaling and vascular development in zebrafish.

Background: The interplay between Notch and Vegf signaling regulates angiogenesis in the embryo. Notch signaling limits the responsiveness of endothelial cells to Vegf to control sprouting. Despite the importance of this regulatory relationship, much remains to be understood about extrinsic factors that modulate the pathway.

Sox18 genetically interacts with VegfC to regulate lymphangiogenesis in zebrafish.

Objective: Lymphangiogenesis is regulated by transcription factors and by growth factor pathways, but their interplay has not been extensively studied so far. We addressed this issue in zebrafish.

Approach And Results: Mutations in the transcription factor-coding gene SOX18 and in VEGFR3 cause lymphedema, and the VEGFR3/Flt4 ligand VEGFC plays an evolutionarily conserved role in lymphangiogenesis.