CLONING OF A GROWTH ARREST-SPECIFIC AND TRANSFORMING GROWTH-FACTOR BETA-REGULATED GENE, TI-1, FROM AN EPITHELIAL-CELL LINE

By cDNA cloning and differential screening, five genes that are regulated by transforming growth factor-beta (TGF-beta) in mink lung epithelial cells were identified. A novel membrane protein gene, TI 1, was identified which was downregulated by TGF-beta and serum in quiescent cells. In actively growing cells, the TI 1 gene is rapidly and transiently induced by TGF-beta, and it is overexpressed in the presence of protein synthesis inhibitors. It appears to be related to a family of transmembrane glycoproteins that are expressed on lymphocytes and tumor cells. The four other genes were all induced by TGF-beta and correspond to the genes of collagen alpha type I, fibronectin, plasminogen activator inhibitor 1, and the monocyte chemotactic cell-activating factor (JE gene) previously shown to be TGF-beta regulated.