Identification of eight novel single-nucleotide polymorphisms at human tissue-type plasminogen activator (t-PA) locus: Association with vascular t-PArelease in vivo

Recently, we reported that an Alu insertion polymorphism of the tissue-type plasminogen activator (t-PA) gene is associated with vascular t-PA release rates in man. In the current study we searched the t-PA gene for putative functional genetic variants in linkage disequilibrium (LD) with this polymo rphism. Healthy individuals with different Alu genotypes and contrasting t- PA release rates were studied. Regulatory and coding regions of the t-PA ge ne were sequenced. Eight single-nucleotide polymorphisms (SNPs) were identi fied. Three of these were in significant LD with the Alu polymorphism and c onsequently associated with t-PA release rates; one in the far upstream enh ancer, one in exon 6, and one in intron 10. The enhancer SNP resides within a GC box. Electrophoretic mobility shift assay (EMSA) revealed a reduced b inding affinity of Spl to the T allele, which is the allele associated with a low t-PA release rate. Variations in exon 6 and intron 10 were silent an d without apparent effect on splicing, respectively.