A basis for differentiating among the multiple human Mu-glutathione S-transferases and molecular cloning of brain GSTM5.
Specific cDNA probes and antisera were employed to interpret genetic polymorphisms of human Mu-class glutathione S-transferases and to provide a basis for identifying individual forms in human tissues. A cDNA probe that cross-hybridized with various human and rodent Mu-glutathione S-transferase transcripts, hybridized with at least three discrete components by Northern analysis of RNA from human tissue. The smallest (1.3 kb) transcript was identified as the one that encodes GSTM3-3 subunits. A form designated GSTM5, was cloned from a human brain cDNA library and its sequence determined. The open reading frame of GSTM5 shared a high degree of homology with the sequences of other Mu-class glutathione S-transferases, but its 846-nucleotide 3'-noncoding region was unique and considerably larger than that of any of the other Mu forms. Specific synthetic peptide antigens were utilized to distinguish among Mu-class glutathione S-transferases in different tissues of representative individuals. The primary hepatic transcript was that encoding GSTM1-1 with much lesser amounts of GSTM3-3, but livers were devoid of GSTM2-2, and GSTM5-5. Immunoblots confirmed that null-phenotype individuals lacked the GSTM1 gene rather than its GSTM2 homologue that is nearly identical in its exon sequences. The null phenotype therefore was conspicuous in liver, where GSTM1-1 ordinarily was the predominant Mu transcript, but brain and testis contained all four forms. A general strategy was devised to distinguish among and assign primary structures to individual glutathione S-transferases from human tissue.
Takahashi
Y
Y
Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.
Campbell
E A
EA
Hirata
Y
Y
Takayama
T
T
Listowsky
I
I
D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain / Q000201:enzymology*; D002675:Child, Preschool; D003001:Cloning, Molecular; D004247:DNA; D005260:Female; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D051381:Rats; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000201:enzymology; D014158:Transcription, Genetic
D004247:DNA; D005982:Glutathione Transferase