INVOLVEMENT OF RETINOIC ACID NUCLEAR RECEPTORS IN RETINOIC ACID-INDUCED TISSUE TRANSGLUTAMINASE GENE-EXPRESSION IN RAT TRACHEAL 2C5 CELLS

The involvement of retinoic acid nuclear receptors (RARs) in the induction of tissue transglutaminase (TG) by retinoic acid in rat tracheal 2C5 cells was determined. The levels of RARα and RARβ were altered in 2C5 cells by transfection with RAR expression vectors. Increased expression of RARα increased the induction of tissue TG by retinoic acid. In contrast, decreased RARα expression, using an antisense RARα expression vector, diminished the normal level of tissue TG induction caused by retinoic acid. Transfectants over expressing RARβ were also more responsive to retinoic acid for the induction of tissue TG, although the magnitude of TG induction was not as great as resulted from RARα overexpression. These results indicate that the levels of the RARα and RARβ dictate the magnitude of tissue TG induction by retinoic acid. © 1991 Academic Press, Inc.