Coordinate regulation of basal and cyclic 5'-adenosine monophosphate (cAMP)-activated expression of human chorionic gonadotropin-alpha by Ets-2 and cAMP-responsive element binding protein.
Ets-2 controls the activities of many genes characteristically up-regulated in trophoblast. One apparent exception has been the gene for the human chorionic gonadotropin subunit alpha (hCGalpha). Here, we show that the hCGalpha gene contains two overlapping Ets binding sites adjacent to an activator protein-1-like site in its proximal promoter. Transactivation by Ets-2 is susceptible to truncation and mutation of these sites, which bind Ets-2 during in vitro mobility shift assays, as well as in vivo as determined by chromatin immunoprecipitation in choriocarcinoma cells. Knockdown of Ets-2 with short interfering RNA decreases both promoter activity and synthesis of hCGalpha. Ets-2 acts in combination with the protein kinase A (PKA) signal transduction pathway to activate the hCGalpha promoter expression. Mutation of the Ets-2 binding sites dramatically reduces up-regulation by PKA, whereas mutations within the two cAMP-responsive elements abolish responsiveness of the promoter to Ets-2. cAMP-responsive element binding protein (CREB) and Ets-2 form a complex that can be coimmunoprecipitated from choriocarcinoma cells, and association of CREB and Ets-2 is increased by activation of PKA. Regulation of hCGalpha subunit gene activity by cAMP involves the binding of CREB and Ets-2 to discrete elements in the promoter as well as a physical interaction between the two proteins. We propose that regulation of hCGalpha by Ets-2 and CREB enables coordinated expression of hCGalpha with its partner hCGbeta subunit.
Ghosh
Debjani
D
Department of Animal Sciences, University of Missouri, Columbia, Missouri 65211-7310, USA.
Sachdev
Shrikesh
S
Hannink
Mark
M
Roberts
R Michael
RM
D001483:Base Sequence; D001665:Binding Sites; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases; D004252:DNA Mutational Analysis; D015292:Glycoprotein Hormones, alpha Subunit / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D017362:Cyclic AMP Response Element-Binding Protein; C494069:ETS2 protein, human; D015292:Glycoprotein Hormones, alpha Subunit; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D015534:Trans-Activators; D000242:Cyclic AMP; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases