Sweet Regulation of Human Glucocorticoid Receptor Transcriptional Activity

This study is to understanding the transcription profile of human Glucocorticoid Receptor GR, gene of a neuroendocrine, stress response and obesity related receptor. For GR, relative luciferase activity RLA and the distribution of phosphorylation [P], glycosylation sites [G] on transcription factor for promoter model were plotted on the same chart. Within the 3.2 kb upstream of the methionine ATG, for GR, trend lines of RLA with that of [G] or ([P]-[G]), both tend to have negative reciprocal relationship. It brings up the question: for the neuendocrine glucocorticoid receptor, does the nutrition and obesity related glycosylation regulated the transcriptional activity in a negative reciprocal way? In conclusion, for GR, the reciprocal relation between trend line of [G], ([P] ± [G]) or [P] and that of RLA, give a specific digit evidence for the first time to the theory, which the structure related glycosylation and the signal sensing phosphorylation, exhibit either independently or Interactively on regulation of transcription activity. Abbreviations RLA: Relative Luciferase Activity; Luciferase/β-Galactosidase Activity; DLA: Dual Luciferase Assay; GR: Human Glucocorticoid Receptor; TF: Transcription Factor; P1: Construct Plasmid 1; P7: Construct Plasmid 7. GR-P1: Construct Plasmid 1 for Human Glucocorticoid Receptor; GR-P7: Constructs Plasmid 7 for Human Glucocorticoid Receptor; [P]: Number of Phosphorylation Sites on TF for Promoter Models; [G]: Number of Glycosylation Sites on TF for Promoter Models; [P]-[G]: Number of Difference between Phosphorylation and Glycosylation Sites on TF for Promoter Models; [P]+[G]: Number for Sum of Phosphoylation and Glycosylation Sites on TF for Promoter Models Introduction Glucocorticoid receptor signaling is in physiological and pathophysiological conditions in the major organ systems in the human body. Among the non-genomic signaling of GRs [1], the rapid actions of GRs, occur as a result of physiochemical interactions of glucocorticoids with the cell membrane; have been reported in various systems, including the cardiovascular, immune and neuroendocrine. In the embryonic development, the present of functional GR during gestation is essential for postnatal survival as well as during development. In the nervous system, GR functions in the brain correlate positively with anxiety behavior. The GR in the forebrain has been shown to regulate the HPA axis and behavior under stressed conditions. In the cardiovascular system, glucocorticoid regulation of cell size, apoptosis, inflammatory state, and vascular tone appears to be vital for proper cardiac function. GR signal is associated with immune system, respiratory system as well as reproductive system. Considerable evidence implicating GR signaling is in maintaining glucose homeostasis, regulating metabolic homeostasis e.g. Cushing’s disease or Addison’s disease. In musculoskeletal system, the activity of GR in skeletal muscle has been shown to correlate positively with metabolic syndrome. And in Integumentary system, the antiproliferative effects of the GR in keratinocytes were shown to be regulated by transrepression, and GR in the skin physiologically regulate epithelial integrity and immune function. And the glucocorticoid receptor plays the dominant role in adipogenesis and adipokine production in human adipocytes [2], On the other hand, primary gene induction or repression in eukaryotes does not require protein synthesis [3], suggesting the involvement of posttranslational modifications [4,5]. Since many different types of stimuli that affect gene expression also lead to the activation of protein kinases, analysis of transcription factor phosphorylation is essential for complete understanding of the signal pathways. The activity of transcription factors may be modulated by their signal-sensing domain including phosphorylation [6]. In addition, as nutrient sensitive sugar modification, glycosylation, interfere with the epigenetic control of gene Research Article iMedPub Journals http://www.imedpub.com/ Obesity & Eating Disorders ISSN 2471-8203 Vol.1 No.1:4 2015 © Copyright iMedPub | This article is available from: 10.4172/2471-8203.100004 1 expression. GR receptors are involved in anxiety, cardiovascular, apoptosis, inflammatory, immune system, respiratory, reproductive system, musculoskeletal and integumentary system diseases, as well as obesity and neuroendocrine disease. Moreover, phosphorylation or glycosylation are perhaps required for the activation of transcription factors. Thus, the regulatory mechanism and post translation modification in the epigenetic transcription regulation of glucocorticoid receptor would be beneficial. Methods For GR, relative luciferase activity (in HeLa (human cervical carcinoma cells) is from Figure 7 in Vedeckis’s paper [7], and the sequence information for the corresponding constructs is from Figure 4 in the same paper. Afterwards, promoter model [8] [A promoter model represents a framework of two or more conserved elements (e.g., transcription factor binding sites) with a defined distance (and strand orientation). Usually, promoter models are much more specific than single elements like transcription factor binding sites. Therefore, a promoter model can give higher evidence that the matching sites are functional was inspected by Genomatix (http:// www.genomatix.com/). The glycosylation (Table 1) and phosphorylation sites (Table 2) on the promoter model were searched by Protein Knowledge bases of Uniprot (http:// www.uniprot.org/). Table 1: Glycosylation site on promoter model of GR. Promoter Model Sequence bp G1 TF EGRF_SP1F_01 GTTGGGGGCGGGGGGCG -3096 G V$SP1F SP1F_SP1F_01 GTTGGGGGCGGGGGGCG -3096 G V$SP1F SP1F_SP1F_06 GTTGGGGGCGGGGGGCG -3096 G V$SP1F SP1F_ETSF_04 GTTGGGGGCGGGGGGCG -3096 G V$SP1F SP1F_KLFS_01 GTTGGGGGCGGGGGGCG -3096 G V$SP1F SP1F_SP1F_06 GCGGGGGGCGAAGCGCG -3089 G V$SP1F SP1F_SP1F_01 GCGGGGGGCGAAGCGCG -3089 G V$SP1F SP1F_SP1F_05 GCGGGGGGCGAAGCGCG -3089 G V$SP1F SP1F_SP1F_01 GCACCGGGCGGGGCGGC -3070 G V$SP1F KLFS_SP1F_01 GCACCGGGCGGGGCGGC -3070 G V$SP1F SP1F_SP1F_06 GCACCGGGCGGGGCGGC -3070 G V$SP1F SP1F_KLFS_01 GCACCGGGCGGGGCGGC -3070 G V$SP1F SP1F_SP1F_05 GCACCGGGCGGGGCGGC -3070 G V$SP1F SP1F_SP1F_01 GGGCGGGGCGGCCACGC -3065 G V$SP1F SP1F_SP1F_06 GGGCGGGGCGGCCACGC -3065 G V$SP1F SP1F_SP1F_01 CGGGGTGGCGGGGCCCG -3015 G V$SP1F E2FF_SP1F_01 GCGGAGGGCGTGGGGGC -2997 G V$SP1F SP1F_NF1F_01 GCGGAGGGCGTGGGGGC -2997 G V$SP1F SP1F_SP1F_01 CGTGGGGGCAGGGACCG -2989 G V$SP1F SP1F_E2FF_01 CCCTCGGGCGGGGAGCG -2906 G V$SP1F SP1F_EBOX_SP1F_01 CCCTCGGGCGGGGAGCG -2906 G V$SP1F SP1F_EBOX_SP1F_01 CCCTCGGGCGGGGAGCG -2906 G V$SP1F E2FF_SP1F_01 GCCGGGGGTGGAGTGGG -2889 G V$SP1F EBOX_EBOX_02 GGAGCGCGTGTGT -2876 G V$EBOX EBOX_EBOX_02 GCGCCACGGCGCG -2852 G V$EBOX SP1F_EBOX_SP1F_01 GCGCCACGGCGCG -2852 G V$EBOX SP1F_EBOX_SP1F_01 GCGCCACGGCGCG -2852 G V$EBOX Obesity & Eating Disorders ISSN 2471-8203 Vol.1 No.1:4 2015 2 This article is available from: 10.4172/2471-8203.100004 SP1F_EBOX_SP1F_01 CGAGCGAGCGGGACCGA -2817 G V$SP1F SP1F_EBOX_SP1F_01 GGCCTGGGCGAGCGAGC -2809 G V$SP1F