LOCALIZATION OF TRANSFORMING GROWTH-FACTOR-BETA TYPE-I AND TYPE-II RECEPTORS IN MOUSE DEVELOPMENT

We have investigated the localization pattern of the transforming grow th factor-beta (TGF-beta) receptors type I (T beta R-I) and type II (T beta R-II) during mouse organogenesis by immunohistochemical analysis . Staining of both receptors was found in many developing organs, e.g. , bone, teeth, Meckel's cartilage, and neural tissues, where the expre ssion of their ligands has been previously reported. During the invest igated stages, expression of T beta R-I was more ubiquitous than that of T beta R-II. T beta R-II preferentially localized in the undifferen tiated mesenchymal cells which subsequently differentiated into bone. There was no staining of T beta R-II in the central nervous system, wh ile intense T beta R-I staining was found specifically in nervous tiss ues. Expression of T beta R-I and T beta R-II was mostly coincident wi th that of their ligands, suggesting that TGF-beta s act as multiple m ediators during organogenesis. In addition, colocalization of both rec eptors in the epithelia of the tooth bud and submandibular gland, whic h were actively invaginating into the mesenchyme, leads us to speculat e that both receptors may be necessary for dynamic epithelial morphoge nesis. (C) 1995 Academic Press, Inc.