CHARACTERIZATION OF GLUCOCORTICOID RESPONSE ELEMENT OF RAT ANGIOTENSIN-II TYPE-1A RECEPTOR GENE

The responsiveness of the rat angiotensin II type 1a and type 1b recep tor (AT1a-R and AT1b-R) genes to glucocorticoid was examined in rat va scular smooth muscle cells (VSMCs) and the glucocorticoid response ele ment (GRE) of the AT1a-R gene was characterized. Glucocorticoid induce d an increase in AT1a-R mRNA levels, whereas AT1b-R mRNA levels were u naffected. The nuclear run-off assay indicated that the transcription of the AT1a-R gene, but not that of the AT1b-R gene, was increased by glucocorticoid. The mRNA stability of AT1a-R was unchanged by glucocor ticoid. Promoter/chrolamphenicol acetyltransferase reporter analysis d emonstrated that the 5'-flanking region of the AT1a-R gene was functio nal in rat VSMCs and established that the GRE motif between -770 to -7 56 could confer glucocorticoid responsiveness on the AT1a-R gene. (C) 1995 Academic Press, Inc.