TY - JOUR
T1 - Dexamethasone responsive element in the rat Na, K-ATPase β 1 gene coding region
AU - Hao, Hong
AU - Rhodes, Richard
AU - Ingbar, David H.
AU - Wendt, Christine H.
PY - 2003/11/30
Y1 - 2003/11/30
N2 - The Na, K-ATPase plays an essential role in active alveolar epithelial fluid resorption. In fetal and adult alveolar epithelial cells, glucocorticoids (GC) increase Na, K-ATPase activity, mRNA levels, and transcription rate of the β1 subunit. In this study, we describe a glucocorticoid responsive element (GRE) in the coding region of the rat Na, K-ATPase β1 gene in a rat lung epithelial cell line. Transient transfection experiments with the β1 subunit coding region with or without the 5′ and 3′ untranslated regions demonstrated responsiveness to dexamethasone induction and also identified a GRE at +434 in exon IV. The +434 GRE conferred dexamethasone responsiveness in a heterologous thymidine kinase promoter irrespective of its orientation to the β 1 promoter. Transcriptional upregulation by dexamethasone was abolished in +434 mutants. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of nuclear proteins to the +434 GRE and the presence of the GC receptor. This specific binding was inhibited by a GRE previously described in the rat Na, K-ATPase β1 gene at -631. In conclusion, we identified a GRE at +434 in the exon IV of the rat Na, K-ATPase β1 gene.
AB - The Na, K-ATPase plays an essential role in active alveolar epithelial fluid resorption. In fetal and adult alveolar epithelial cells, glucocorticoids (GC) increase Na, K-ATPase activity, mRNA levels, and transcription rate of the β1 subunit. In this study, we describe a glucocorticoid responsive element (GRE) in the coding region of the rat Na, K-ATPase β1 gene in a rat lung epithelial cell line. Transient transfection experiments with the β1 subunit coding region with or without the 5′ and 3′ untranslated regions demonstrated responsiveness to dexamethasone induction and also identified a GRE at +434 in exon IV. The +434 GRE conferred dexamethasone responsiveness in a heterologous thymidine kinase promoter irrespective of its orientation to the β 1 promoter. Transcriptional upregulation by dexamethasone was abolished in +434 mutants. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of nuclear proteins to the +434 GRE and the presence of the GC receptor. This specific binding was inhibited by a GRE previously described in the rat Na, K-ATPase β1 gene at -631. In conclusion, we identified a GRE at +434 in the exon IV of the rat Na, K-ATPase β1 gene.
KW - Enhancer
KW - Gene regulation
KW - Glucocorticoid receptor
KW - Glucocorticoid response element
KW - Ion transport
KW - Sodium pump
UR - http://www.scopus.com/inward/record.url?scp=0345549647&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0345549647&partnerID=8YFLogxK
U2 - 10.1016/j.bbaexp.2003.09.003
DO - 10.1016/j.bbaexp.2003.09.003
M3 - Article
C2 - 14654235
AN - SCOPUS:0345549647
SN - 0167-4781
VL - 1630
SP - 55
EP - 63
JO - Biochimica et Biophysica Acta - Gene Structure and Expression
JF - Biochimica et Biophysica Acta - Gene Structure and Expression
IS - 2-3
ER -