The structure of the rat glutathione S-transferase P gene and related pseudogenes.

We have isolated the rat placental-type glutathione S-transferase (GST-P) gene from a lambda phage library using GST-P cDNA clone, pGP5 (Sugioka, Y., Kano, T., Okuda, A., Sakai, M., Kitagawa, T., and Muramatsu, M. (1985) Nucleic Acids Res. 13, 6049-6057), as a probe. The rat GST-P gene is about 3 kilobase pairs long and contains 7 exons and 6 introns, encoding the same GST-P protein specified by pGP5. The cap site maps 70 nucleotides upstream from the translation initiation site. The canonical promoter "TATA" box was found 27 base pairs upstream from the putative cap site. Two hundred base pairs upstream from the cap site are rich in G + C residues (61%), and the hexanucleotide sequence 5'-GGGCGG-3' is found at position -47 to -42. We have also isolated several processed-type pseudogenes which were presumably originated by reverse transcription followed by insertion at target sites.