title: 17β-estradiol regulates the expression of apolipoprotein M through estrogen receptor α-specific binding motif in its promoter.
abstract: BACKGROUND
  We have previously demonstrated that estrogen could significantly enhance expression of apolipoprotein M (apoM), whereas the molecular basis of its mechanism is not fully elucidated yet. To further investigate the mechanism behind the estrogen induced up-regulation of apoM expression.
  
  
  RESULTS
  Our results demonstrated either free 17β-estradiol (E2) or membrane-impermeable bovine serum albumin-conjugated E2 (E2-BSA) could modulate human apoM gene expression via the estrogen receptor alpha (ER-α) pathway in the HepG2 cells. Moreover, experiments with the luciferase activity analysis of truncated apoM promoters could demonstrate that a regulatory region (from-1580 to -1575 bp (-GGTCA-)) upstream of the transcriptional start site of apoM gene was essential for the basal transcriptional activity that regulated by the ER-α. With the applications of an electrophoresis mobility shift assay and a chromatin immunoprecipitation assay, we could successfully identify a specific ER-α binding element in the apoM promoter region.
  
  
  CONCLUSIONS
  In summary, the present study indicates that 17β-estradiol induced up-regulation of apoM in HepG2 cells is through an ER-α-dependent pathway involving ER-α binding element in the promoter of the apoM gene.
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Wei
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Guang-Hua
authors.initials: GH
authors.lastname: Luo
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Feng
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Yuan-Ping
authors.initials: YP
authors.lastname: Shi
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Qin-Feng
authors.initials: QF
authors.lastname: Mu
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Miao-Mei
authors.initials: MM
authors.lastname: Yu
authors.affiliation: Department of Comprehensive Laboratory, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Pan
authors.affiliation: Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85, Lund, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Berggren-Söderlund
authors.affiliation: Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85, Lund, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Nilsson-Ehle
authors.affiliation: Cardiothoracic Surgery, the Third Affiliated Hospital of Soochow University, Changzhou, 213003, China.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: Division of Clinical Chemistry and Pharmacology, Department of Laboratory Medicine, Lunds University, S-221 85, Lund, Sweden. ning.xu@med.lu.se.
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
mesh_terms: D001053:Apolipoproteins / Q000235:genetics* / Q000378:metabolism; D000075243:Apolipoproteins M; D001483:Base Sequence; D001665:Binding Sites; D004958:Estradiol / Q000502:physiology*; D047628:Estrogen Receptor alpha / Q000502:physiology*; D056945:Hep G2 Cells; D006801:Humans; D054834:Lipocalins / Q000235:genetics* / Q000378:metabolism; D061986:MCF-7 Cells; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017422:Sequence Analysis, DNA; D015533:Transcriptional Activation; D015854:Up-Regulation
chemical_list: C400523:APOM protein, human; D001053:Apolipoproteins; D000075243:Apolipoproteins M; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D054834:Lipocalins; D004958:Estradiol
keywords: Apolipoprotein M; Chromatin Immunoprecipitation (ChIP) assay; Electrophoretic mobility shift assay (EMSA); Estrogen receptor alpha; Estrogen responsive element