title: Upregulation of mineralocorticoid- and glucocorticoid-receptor gene expression by Sp-I.
abstract: The mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) belong to the steroid/thyroid hormone superfamily of ligand-induced transcription factors. Both activate the human Na/K ATPase alpha1 and beta1 genes transcriptionally. To assess the role of the transcription factor Sp1 and the nuclear factor I (NF-I), in MR- and GR-mediated gene expression using the human Na/K ATPase beta1 full-length promoter, we have examined the functions of Sp-I and NF-I functions in two different cell lines, COS-1 and T-84. By transient transfections we have shown that Sp-I significantly enhances MR and GR expression, whereas NF-I had negligible effect. We propose that the transcriptional enhancement could be through a direct interaction physically between MR or GR with Sp1 that allows other factors to bind the responsive element resulting in synergistic upregulation of transcription.
mesh_terms: D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D019556:COS Cells; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D011965:Receptors, Glucocorticoid / Q000235:genetics*; D018161:Receptors, Mineralocorticoid / Q000235:genetics*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D015533:Transcriptional Activation; D014162:Transfection; D015854:Up-Regulation; D051840:Y-Box-Binding Protein 1