A mouse bone marrow stromal cell line, TBR-B, shows inducible expression of smooth muscle-specific genes

We established an in vitro culture system which mimicked the differentiatio n pathway of smooth muscle cell, using TBR-B, a bone marrow stromal cell li ne derived from transgenic mice harboring temperature-sensitive SV40 large T-antigen gene. TBR-B cells have the potential to express smooth muscle-spe cific genes including h1-calponin, h-caldesmon, SM22 alpha and alpha-actin, only after cultured in the differentiation medium for 2 weeks. The differe ntiation state of TBR-B was well controlled by using different culture medi um, Using this cell line, we also found that ascorbic acid is a potent fact or inducing the expression of h1-calponin and alpha-actin. TBR-B cells will serve as a useful tool for elucidating the regulatory mechanisms of smooth muscle-specific gene expression, and for identifying compounds that regula te the differentiation state of vascular smooth muscle cells. (C) 2000 Fede ration of European Biochemical Societies, Published by Elsevier Science B.V . All rights reserved.