Dynamic expression of TSC-22 at sites of epithelial-mesenchymal interactions during mouse development

The leucine zipper transcription factor TSC-22 (TGF-beta 1 Stimulated Cnone -22) was first isolated from a mouse osteoblast cell line as an immediate-e arly target gene of TGF-beta 1. However, work with other cell lines, as wel l as with a Drosophila homolog, bunched, suggests that it is an effector ge ne of various growth factors and potentially involved in the integration of multiple extracellular signals. Throughout mouse embryogenesis TSC-22 is e xpressed in a dynamic pattern. Although early TSC-22 expression is ubiquito us in 6.5 day embryos, as development proceeds TSC-22 expression is upregul ated at sites of epithelial-mesenchymal interactions such as the limb bud, tooth primordiurn, hair follicle, kidney, lung, and pancreas. TSC-22 is als o expressed in many neural crest-derived tissues including the mesenchyme o f the branchial arches, the cranial, dorsal root, and sympathetic ganglia, as well as the facial cartilage and bone. Other areas of expression are the otic and optic vesicles, the heart, and cartilage and bone forming regions throughout the embryo. (C) 1999 Elsevier Science Ireland Ltd. All rights r eserved.