Distribution of PAI-1 promoter 4G/5G polymorphism in healthy Chinese and functional characterization using a luciferase reporter vector

The aim of this study was to analyze the distribution of plasminogen activator inhibitor-1 (PAI-1) promoter 4G/5G polymorphism in healthy Chinese and compare the transcription activity of the two PAI-1 promoters using luciferase reporter vector pGL(3). PAI-1 promoter 4G/5G polymorphism was analyzed in 77 healthy Chinese using allele-specific polymerase chain reaction (PCR). The PAI-1 promoters from individuals homozygous for the insertion (5G) and deletion (4G) were cloned into luciferase reporter vector pGL3, respectively. The transcription activities of the two promoters (PAI-14G and PAI-1-5G) were then compared using the luciferase reporter vectors expressed in ECV304 and HepG(2) cell lines. Among the 77 healthy Chinese the genotype frequency for 4G/4G, 4G/5G, and 5G/5G was 49.1, 44.1, and 6.5%, respectively. Both of the two PAI-1 promoters cloned into luciferase reporter vector pGL3, expressed very well both in ECV304 and HepG2, and have similar basic transcription activity. Thrombin ( 10-20 U/ ml) has no effects on the transcription activity of the two promoters expressed in ECV304, while in the HepG2 cell line interleukin- 1 ( IL-1) 158 U/ ml increased the transcription activity of PAI-1- 4G by 67% ( p<0.05, n= 5) without effects on PAI- 1- 5G transcription activity. The distribution of PAI- 1 promoter 4G/5G polymorphism in Chinese is obviously different from that in Caucasians with the 4G allele more frequently found in Chinese. PAI-1 promoter 4G/5G polymorphism does not alter basic transcription activity and 4G promoter has increased response to IL-1.