title: A novel polymorphism in the PAI-1 gene promoter enhances gene expression. A novel pro-thrombotic risk factor?
abstract: BACKGROUND
  Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of tissue-type plasminogen activator in plasma and the most important regulator of the fibrinolytic pathway. The 4G/5G polymorphism (rs1799889) in the PAI-1 promoter is associated with altered PAI-1 transcription. We have identified a new 4G/5G allele, in which a T is inserted near the 4G tract or replaces a G in the 5G tract, forming a T plus 4G (T4G) region.
  
  
  METHODS
  This new variant was first identified in two women, one had experienced juvenile myocardial infarction, the other repeated miscarriage; both had increased PAI-1 plasma activity. In view of the important influence of this promoter region on PAI-1 protein plasma level, we performed in vitro evaluation of the effects of the T4G variant on the transcription activity of the PAI-1 gene promoter.
  
  
  CONCLUSIONS
  In silico prediction analysis showed that presence of the T4G allele disrupts the E-Box region upstream of the T4G variant, altering the affinity of the target sequence for E-Box binding factors like upstream stimulatory factor-1 (USF-1). Basal T4G promoter activity was 50% higher compared to 4G and 5G variants, but it was less stimulated by USF-1 overexpression. We also analyzed the effects of IL-1β and IL-6 on the PAI-1 promoter activity of our three constructs and showed that the T4G variant was less affected by IL-1β than the other variants. These findings indicate that the T4G variant may be a novel risk factor for thrombotic events.
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy.
authors.forename: Renato
authors.initials: R
authors.lastname: Liguori
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy.
authors.forename: Sandro
authors.initials: S
authors.lastname: Quaranta
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Di Fiore
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Università Telematica Pegaso, Naples, Italy.
authors.forename: Ausilia
authors.initials: A
authors.lastname: Elce
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy. Electronic address: giuseppe.castaldo@unina.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Castaldo
authors.affiliation: CEINGE-Biotecnologie Avanzate scarl, Naples, Italy; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy.
authors.forename: Felice
authors.initials: F
authors.lastname: Amato
mesh_terms: D000328:Adult; D001483:Base Sequence; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012307:Risk Factors; D013927:Thrombosis / Q000235:genetics*
chemical_list: D017395:Plasminogen Activator Inhibitor 1
keywords: Fibrinolytic disorders; Gene; PAI-1; Single-nucleotide polymorphism; Thrombotic risk