title: The promoter of cell growth- and RNA protection-associated SND1 gene is activated by endoplasmic reticulum stress in human hepatoma cells.
abstract: BACKGROUND
  Staphyloccocal nuclease domain-containing protein 1 (SND1) is involved in the regulation of gene expression and RNA protection. While numerous studies have established that SND1 protein expression is modulated by cellular stresses associated with tumor growth, hypoxia, inflammation, heat-shock and oxidative conditions, little is known about the factors responsible for SND1 expression. Here, we have approached this question by analyzing the transcriptional response of human SND1 gene to pharmacological endoplasmic reticulum (ER) stress in liver cancer cells.
  
  
  RESULTS
  We provide first evidence that SND1 promoter activity is increased in human liver cancer cells upon exposure to thapsigargin or tunicamycin or by ectopic expression of ATF6, a crucial transcription factor in the unfolded protein response triggered by ER stress. Deletion analysis of the 5'-flanking region of SND1 promoter identified maximal activation in fragment (-934, +221), which contains most of the predicted ER stress response elements in proximal promoter. Quantitative real-time PCR revealed a near 3 fold increase in SND1 mRNA expression by either of the stress-inducers; whereas SND1 protein was maximally upregulated (3.4-fold) in cells exposed to tunicamycin, a protein glycosylation inhibitor.
  
  
  CONCLUSIONS
  Promoter activity of the cell growth- and RNA-protection associated SND1 gene is up-regulated by ER stress in human hepatoma cells.
authors.forename: Sandra
authors.initials: S
authors.lastname: Armengol
authors.forename: Enara
authors.initials: E
authors.lastname: Arretxe
authors.forename: Leire
authors.initials: L
authors.lastname: Enzunza
authors.forename: Sarai
authors.initials: S
authors.lastname: Mula
authors.forename: Begoña
authors.initials: B
authors.lastname: Ochoa
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Chico
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, Leioa, 48940, Spain. mariajose.martinez@ehu.es.
authors.forename: María José
authors.initials: MJ
authors.lastname: Martínez
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D002455:Cell Division; D045744:Cell Line, Tumor; D004720:Endonucleases; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics*; D012313:RNA / Q000235:genetics*
chemical_list: D009687:Nuclear Proteins; D012313:RNA; D004720:Endonucleases; C095221:SND1 protein, human