Structure of the human genomic glutathione S-transferase-π gene

The complete human genomic glutathione-S-transferase-π gene (GST-π) was isolated from a λ Charon 4A bacteriophage library which was screened by hybridization to a human GST-π cDNA. We have sequenced 4261 bp which include the entire GST-π gene as well as over 1200 bp of the 5' and 200 bp of the 3' flanking regions. The GST-π gene has 7 exons and 6 introns contained within approximately 2.8 kilobases. Primer extension experiments identified four possible transcription start points closely spaced between 29 and 33 nucleotides (nt) 5' to the start of translation. Analysis of the GST-π promoter region revealed 4 putative transcription regulatory motifs; these sequences include a 'TATA' box 29 bp upstream from the major transcription start point (nt position -29), 2 Sp1 recognition sequences (GGGCGG, nt positions -46 to -41 and -56 to -51), and an AP-1 recognition sequence (TGACTCA, nt positions -69 to -63). The first 200 nt 5' to the start point of transcription contain a G + C-rich region (79%). Additionally, an intriguing A + T-rich region was found between nt positions -505 and -413 which contained 17 AAAAT tandem repeats. Comparison of the GST-π gene with the homologous rate gene, GST-P, disclosed extensive conservation of genomic organization between the two species.