Sequence analysis and regulation of rat liver glutathione S-transferase mRNAs

Abstract

1. We have utilized polysomal immunoadsorption techniques to purify the rat liver glutathione S-transferase mRNAs. Using the purified mRNAs as template, cDNA clones complementary to the Ya, Yb₁, and Yc mRNAs have been constructed. The cDNA clones have been utilized in RNA blot hybridization and nuclear run-off assays to demonstrate that the Ya and Yb mRNAs are elevated 8 and 5-fold, respectively by phenobarbital; whereas the Yc mRNA is elevated only 2·0-fold.

2. The elevation in glutathione S-transferase mRNAs is due in part to transcriptional activation of the corresponding genes. Nucleotide sequence analysis of the three glutathione S-transferase clones suggest that the Ya and Yc genes represent one rat liver glutathione S-transferase gene family whereas the Yb genes represent a second distinct glutathione S-transferase gene family.

3. The construction of these cDNA clones will allow identification and characterization of the glutathione S-transferase structural genes as well as aid in the identification of regulatory elements that are responsible for transcriptional activation of the genes by xenobiotics.