Antibodies directed against the chicken type II TGF beta receptor identifyendothelial cells in the developing chicken and quail

Due to the availability of the endothelial cell marker QH1, experiments usi ng quail embryos have traditionally been used to trace the endothelial cell lineage and describe the morphologic events of vessel formation. A compara ble marker in the chicken has not been available. Here we report that antib odies raised against the extracellular domain of the chicken type II TGF be ta receptor (TBRII) preferentially identify endothelial cells in the chick. Endothelial cells can first be identified in the 6-somite chick embryo by TBRII expression. TBRII expression in 12- and aa-somite chick and quail emb ryos was found to directly correlate with the endothelial QH1 staining patt ern in quail, This preferential labeling of endothelial cells persists unti l at least embryonic day 10 in the chick. These data indicate that antibodi es to TBRII are an effective marker of endothelial cells in chick and provi de useful reagents for the evaluation of vascular patterning. (C) 1999 Wile y-Liss,Inc.