Binding between Crossveinless-2 and Chordin von Willebrand factor type C domains promotes BMP signaling by blocking Chordin activity.

Background: Crossveinless-2 (CV2) is an extracellular BMP modulator protein of the Chordin family, which can either enhance or inhibit BMP activity. CV2 binds to BMP2 via subdomain 1 of the first of its five N-terminal von Willebrand factor type C domains (VWC1). Previous studies showed that this BMP binding is required for the anti-, but not for the pro-BMP effect of CV2.

The transcription factors Scl and Lmo2 act together during development of the hemangioblast in zebrafish.

The transcription factors Scl and Lmo2 are crucial for development of all blood. An important early requirement for Scl in endothelial development has also been revealed recently in zebrafish embryos, supporting previous findings in scl(-/-) embryoid bodies. Scl depletion culminates most notably in failure of dorsal aorta formation, potentially revealing a role in the formation of hemogenic endothelium.

The "Ets" factor: vessel formation in zebrafish--the missing link?

The zebrafish offers a powerful model for studying the development of new blood vessels.

Scl is required for dorsal aorta as well as blood formation in zebrafish embryos.

Blood and endothelial cells arise in close association in developing embryos, possibly from a shared precursor, the hemangioblast, or as hemogenic endothelium. The transcription factor, Scl/Tal1 (stem cell leukemia protein), is essential for hematopoiesis but thought to be required only for remodeling of endothelium in mouse embryos. By contrast, it has been implicated in hemangioblast formation in embryoid bodies.