Differential expression of neuropilin-1 and neuropilin-2 in arteries and veins

Neuropilin-1 (np1) and neuropilin-2 (np2) are receptors for class-3 semapho rins and for several isoforms of VEGF. We have cloned and characterized two chick isoforms of np2 cDNA. Expression patterns of npl, np2, and ephrin-B2 were compared in the developing vascular system of 24-72 h old chick embry os. We show for the first time that np2 is expressed in blood vessels in vi vo from the earliest stages of their formation. In contrast to ephrin-B2, b oth np1 and np2 are expressed in blood islands of 24 h old chick embryos. A t 48-72 h, npl expression is localized preferentially in arteries with an e xpression pattern that resembles that of ephrin-B2. In contrast, np2 is exp ressed preferentially in veins. Thus, neuropilins may play a role in determ ining the arterial or venous identity of blood vessels. (C) 2001 Elsevier S cience Ltd. All rights reserved.