ETAR gene (ortholog gene in mouse was Ednra) encodes endothelin-A receptor, a member of the endothelin receptor group of G-protein-coupled receptors. consist of an extracellular glycosylated N-terminal domain followed by transmembrane regions containing seven hydrophobic α-helices. The transmembrane domains are linked via three shorter extracellular and intracellular loops. ETAR located primarily in the vascular endothelial cells where they play a role in vasoconstriction, vasodilation, bronchoconstriction and cell proliferation. ETAR activation by its natural ligand, the potent vasoconstrictor endothelin 1, also mediates similar physiologic functions, but most importantly plays a role in the regulation of normal blood flow through alternate vasoconstriction and vasodilation, as endothelin 1 binds to ETAR and other endothelin receptors.
mRNA and protein expression analysis
Strain specific analysis of ETAR gene expression in B-ETAR mice by RT-PCR and flow cytometry. A. Mouse Ednra mRNA was detectable in lung of C57BL/6 (+/+) mice. Human ETAR mRNA was detectable only in homozygous B-hETAR mice (H/H) but not in wild-type mice. B. Monocytes and macrophages of bone marrow from C57BL/6 and B-hETAR mice (H/H) were analyzed by flow cytometry with anti-ETAR antibodies. ETAR was detectable in C57BL/6 and homozygous B-hETAR mice. This anti-mouse ETAR antibody also cross reacts with human ETAR. Taken together with RT results, B-hETAR mice successfully express human ETAR protein.