Epidermal growth factor induces H+,K+-ATPase alpha-subunit gene expression through an element homologous to the 3' half-site of the c-fos serum response element.
Epidermal growth factor (EGF) acutely inhibits acid secretion; however, prolonged administration of EGF has been reported to increase acid production. We undertook these studies to examine whether the physiological effects of EGF on acid secretion are mediated by regulation of gastric H+,K+-ATPase, the principle enzyme responsible for acid secretion. EGF in concentrations equivalent to those in plasma increased H+,K(+)-ATPase alpha-subunit mRNA levels. Using H+,K(+)-ATPase-luciferase constructs transfected into primary cultured parietal cells, a significant step up in EGF inducibility was observed between bases -162 and -156 (5'-GACATGG-3') relative to the cap site. This EGF response element (ERE) conferred EGF inducibility when linked to homologous and heterologous promoters. The ERE is homologous to the 3' half-site of the c-fos serum response element to which rNFIL-6, rE12, and SRE-ZBP bind. Electrophoretic mobility shift assays using an ERE probe and parietal cell nuclear extracts revealed a specific DNA-protein complex, the formation of which was changed by neither E12 and NFIL-6 consensus oligonucleotides nor antibodies for NFIL-6, SRE-ZBP, and E12. Our studies indicate that EGF induces gastric H+,K(+)-ATPase alpha-subunit gene expression via an interaction between a specific ERE and a novel transcriptional factor and that this may be a physiologic mechanism by which EGF regulates acid secretion.
Kaise
M
M
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0368, USA.
Muraoka
A
A
Yamada
J
J
Yamada
T
T
D000632:Aminopyrine / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005744:Gastric Acid / Q000378:metabolism*; D005748:Gastric Fundus / Q000166:cytology / Q000378:metabolism; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017930:Genes, Reporter; D016762:Genes, fos / Q000235:genetics; D019833:Genistein; D017506:H(+)-K(+)-Exchanging ATPase / Q000096:biosynthesis*; D006632:Histamine / Q000494:pharmacology; D007529:Isoflavones / Q000494:pharmacology; D008969:Molecular Sequence Data; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D007529:Isoflavones; D011993:Recombinant Fusion Proteins; D000632:Aminopyrine; D004815:Epidermal Growth Factor; D006632:Histamine; D002217:Carbachol; D019833:Genistein; D017506:H(+)-K(+)-Exchanging ATPase