title: [Regulation of Smad ubiquitination regulatory factor 1 expression by NF-κB].
abstract: OBJECTIVE
  To identify a nuclear factor κB (NF-κB) responsive element within the Smad ubiquitination regulatory factor 1 (SMURF1) gene promoter, and to demonstrate its role in the regulation of SMURF1 expression.
  
  
  METHODS
  A series of truncated luciferase reporter plasmids of the SMURF1 promoter were constructed and transfected into hepatic cancer Hep G2 cells. Luciferase assays were carried out to assess the activities of such promoters. DNA binding and chromatin immunoprecipitation (ChIP) assays were used to identify an NF-κB responsive element within the SMURF1 promoter. Lucifease plasmid with mutated NF-κB site was constructed and its activity was assessed. The expression of SMURF1 in Hep G2 cells was detected after transfection of NF-κB specific small interfering RNA (siRNA).
  
  
  RESULTS
  The SMURF1 promoter showed a high transcription activity, and the region of -519 to -378 was demonstrated to be a positive regulatory region. -411 to -420 of the SMURF1 promoter was an NF-κB responsive element, and NF-κB may specifically bind to this site. Mutation of this element may prominently decrease the activity of the promoter. Transfection of NF-κB siRNA evidently down-regulated SMURF1 expression.
  
  
  CONCLUSIONS
  NF-κB can specifically bind to the -411 to -420 region of the SMURF1 promoter and plays an essential role in the expression of SMURF1.
authors.affiliation: Armed Police Forces, Shenyang, Liaoning 110034, P. R. China. janetlee1976@126.com.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
authors.forename: Hongjun
authors.initials: H
authors.lastname: Zhang
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Hu
authors.forename: Tao
authors.initials: T
authors.lastname: Luan
authors.forename: Fangjie
authors.initials: F
authors.lastname: Chen
mesh_terms: D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006801:Humans; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014158:Transcription, Genetic; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism
chemical_list: D016328:NF-kappa B; C498342:SMURF1 protein, human; D044767:Ubiquitin-Protein Ligases