title: Porcine glucocorticoid receptor (NR3C1) gene: tissue-specificity of transcriptional strength and glucocorticoid responsiveness of alternative promoters.
abstract: Glucocorticoid receptor (GR) is transcribed in a tissue- and cell-specific manner with multiple exon 1 mRNA variants driven by selective promoters. We recently cloned and characterized the 5.3kb proximal promoter sequence of porcine GR gene containing 7 untranslated alternative first exons each processed by a distinct promoter. In this study, we showed tissue-specific expression of total GR and its exon 1 mRNA variants in hippocampus, muscle and liver of pigs. Total GR mRNA was most abundant in liver, followed by muscle and hippocampus in descending order. Among all the GR exon 1 mRNA variants detected, GR exon 1-9/10 and 1-4 were the most predominant variants in all the three tissues. The abundance of GR exon 1-4 mRNA was similar to that of 1-10 in muscle, but was significantly lower than 1-10 in liver and hippocampus. The activities of truncated short (S) and long (L) promoters of respective GR exon 1 mRNA variants were analyzed by luciferase reporter assay in 3 representative cell lines, SY5Y, C2C12 and HepG2. S1-10 and S1-4 demonstrated significantly higher activities than other short promoters in all the cell lines examined. Nevertheless, the strongest activity and cell specificity were detected for L1-10 promoter, which was consistent with the predominant exon 1-9/10 expression in porcine tissues. Moreover, with 3 potential nGRE binding sites, L1-10 promoter was more sensitive to dexamethasone (DEX) in HepG2. Our data provide basic knowledge of the transcriptional mechanism underlying the tissue- and cell-specific expression of porcine GR under basal or ligand-stimulated conditions.
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
authors: Zheng
authors: Z
authors: Jiang
authors: Department of Pathophysiology, Institute of Basic Medical Sciences, Beijing, PR China.
authors: Lu
authors: L
authors: Qian
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
authors: Huafeng
authors: H
authors: Zou
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
authors: Yimin
authors: Y
authors: Jia
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
authors: Yingdong
authors: Y
authors: Ni
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
authors: Xiaojing
authors: X
authors: Yang
authors: Department of Animal Sciences, Washington State University, Pullman, WA, United States.
authors: Zhihua
authors: Z
authors: Jiang
authors: Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: zhao.ruqian@gmail.com.
authors: Ruqian
authors: R
authors: Zhao
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D005938:Glucocorticoids / Q000494:pharmacology / Q000502:physiology; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D015735:Mifepristone / Q000494:pharmacology; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism; D034421:Sus scrofa / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D005938:Glucocorticoids; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D015735:Mifepristone; D003907:Dexamethasone
keywords: First exon variants; Glucocorticoid responsiveness; Porcine glucocorticoid receptor; Promoter activity; Tissue-specificity