An in-frame trinucleotide repeat in the coding region of the human cellular glutathione peroxidase (GPX1) gene: in vivo polymorphism and in vitro instability.
We report the variation in vivo and instability in vitro of an in-frame GCG trinucleotide repeat in the human cellular glutathione peroxidase (GPX1) gene. In a population study of 110 alleles from 55 unrelated individuals, the allele frequencies for 4, 5, and 6 GCG repeats were 0.40, 0.35, and 0.25, respectively. No allele was associated with diminished enzyme activity. Current stocks of HL-60 cells, a human myeloid leukemia cell line, are homozygous for the 6-repeat allele. Early passage HL-60 cells frozen in 1976 show a 4/6 genotype and "intermediate" passage cells frozen in 1985 contain both 4/6 and 5/6 genotypes. Thus, the expansion of the repeat appears to have developed in the course of multiple passages of the rapidly proliferating cell line.
Shen
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Department of Pediatrics, University of Massachusetts Medical School, Worcester 01655.
Townes
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Padden
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Newburger
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D000483:Alleles; D001483:Base Sequence; D002893:Chromosomes, Human, Pair 3; D004273:DNA, Neoplasm / Q000235:genetics; D005787:Gene Frequency; D005796:Genes; D005838:Genotype; D005979:Glutathione Peroxidase / Q000235:genetics*; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology; D018598:Minisatellite Repeats; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D005979:Glutathione Peroxidase