As shown in Figure 2, all GSTs fall into three main branches that are comprised of eleven sub-branches, with GSTK solely in a clade, MAPEGs in a clade, and GSTO
, GSTZ, GSTR, GSTA, GSTP, GSTM and GSTT in a clade, respectively.
In particular, previous studies showed that AS3MT and non-AS3MT proteins such as USMG and GSTO can reduce pentavalent arsenic and facilitate transfer of arsenic intermediates as well as antioxidant depletion within and between cells (Hughes 2002; Lefort et al.
GSTO and AS3MT genetic polymorphisms and differences in urinary arsenic concentrations among residents in Bangladesh.
Functional characterization of two variant human GSTO 1-1s (Ala140Asp and Thr217Asn).
We report the results of a screen for genetic association with urinary arsenic metabolite levels in three arsenic metabolism candidate genes, PNP, GSTO, and CYT19, in 135 arsenic-exposed subjects from the Yaqui Valley in Sonora, Mexico, who were exposed to drinking water concentrations ranging from 5.5 to 43.3 ppb.
To date, the arsenic literature specifically supports three genes as being involved in arsenic biotransformation: purine nudeoside phosphorylase (PNP), glutathione-S-transferase omega (GSTO), and arsenic(III) methyltransferase (CYT19) (Lin et al.
To address the need for genetic association studies aimed at testing the hypothesis of the existence of genetic determinants of interindividual variability in human arsenic metabolism, we used existing polymorphism catalogs for GSTO and PNP, produced a resequencing-derived catalog of polymorphisms in CYT19 (no such resequencing-based catalog was publicly available), and tested 23 polymorphic sites within these three genes in a population of arsenic-exposed subjects from the Yaqui Valley area of Sonora, Mexico, who had been phenotyped for the levels of urinary metabolites of arsenic.
We have previously published the resequencing results for GSTO and PNP (Yu et al.