Expression and chromosomal mapping of mouse Gpx2 gene encoding the gastrointestinal form of glutathione peroxidase, GPX-GI.
GPX-GI is a cytosolic tetrameric Se-dependent glutathione peroxidase, similar in properties to GPX-1. Unlike the almost ubiquitous GPX-1, GPX-GI is mainly expressed in the epithelium of gastrointestinal tract. GPX-GI contributes to at least fifty percent of GPX activity in rodent small intestinal epithelium. The total GPX activity consists of at least 70% of selenium-dependent GPX activity in this compartment. By analyzing a panel of mouse interspecies DNA from the Jackson Laboratory's backcross resource, we mapped Gpx2 gene to mouse chromosome 12 between D12Mit4 and D12Mit5, near the Ccs1 locus which contains a colon cancer susceptibility gene. A pseudogene, Gpx2-ps is mapped to mouse chromosome 7. Comparison of Gpx2 gene expression in three pairs of C57BL/6Ha and ICR/Ha mice which are respectively resistant and sensitive to dimethylhydrazine-induced colon cancer, we found a higher Gpx2 mRNA level in C57BL/6Ha colon than ICR/Ha colon. Interestingly, a lower level of GPX activity is found in the resistant strain of mice. Because GPX-1 has three times higher specific activity than GPX-GI, our data suggest that the decreased GPX activity may result from a higher level of Gpx2 gene expression in those cells co-express Gpx1 gene.
Chu
F F
FF
Department of Medical Oncology, City of Hope Medical Center, Duarte, CA 91010, USA.
Esworthy
R S
RS
Ho
Y S
YS
Bermeister
M
M
Swiderek
K
K
Elliott
R W
RW
D000595:Amino Acid Sequence; D000818:Animals; D004064:Digestive System / Q000201:enzymology*; D005979:Glutathione Peroxidase / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D005979:Glutathione Peroxidase