Expression of the platelet‐derived growth factor β receptor during organogenesis and tissue differentiation in the mouse embryo

Abstract

In this study we used in situ hybridization to localize expression of the platelet‐derived growth factor β (PDGFβ) receptor mRNA during organogenesis in the mouse embryo (E 9.5–16.5). Expression was first seen in periaortic mesenchyme (E 9.5–10.5). Later (E 12.5–E 16.5), the receptor was expressed in the mesenchymal component of many developing tissues and organs, particularly derivatives of the primitive gut. The expression was exceptionally high in mesenchyme directly supporting an epithelium, typical of many developing organs such as the trachea and intestine. However, as the mesenchyme differentiated into smooth muscle, PDGFβ receptor mRNA was no longer detected. The expression of the PDGFβ receptor mRNA in mesenchymal components of developing organs, along with its absence in epithelial tissues, indicates that it may play a role in mesenchymal‐epithelial interactions during organ development. Somewhat unexpectedly, the PDGFβ receptor was highly expressed in the endothelium of small blood vessels and vascular structures such as the hyaloid plexus and choroid plexus. In large blood vessels, PDGFβ receptor mRNA was found in the mesenchyme surrounding the endothelium. This suggests that the PDGFβ receptor is involved in growth and development of blood vessels. © 1994 Wiley‐Liss, Inc. Copyright © 1994 Wiley‐Liss, Inc.