The secreted integrin ligand nephronectin is necessary for forelimb formation in Xenopus tropicalis

►The Xenopus tropicalis mutation xdm lacks all forelimb structures. ►Xdm results from a transgene integration in the nephronectin gene. ►Xdm tadpoles do not express tbx5 in the prospective forelimb field. ►Xdm is the first insertional mutation cloned in amphibians.