STRUCTURAL ORGANIZATION, CHROMOSOMAL LOCALIZATION, EXPRESSION AND PHYLOGENETIC EVALUATION OF MOUSE GLUTATHIONE-PEROXIDASE ENCODING GENES

We have reported earlier the cloning and the chromosomal localization of 2 GPX-encoding sequences expressed differentially within the mouse epididymis, gpx5 and gpx3. Here, we have mapped on the mouse chromosom es the third Known murine GPX-encoding gene, the cytosolic GPX or gpx1 . We have compared the degree of identity of the 3 GPX proteins, the r espective organization of the 3 corresponding single copy genes and, u sing degenerated oligonucleotides designed in highly conserved domains of the proteins, we have analyzed the expression of GPX-encoding gene s in the mouse epididymis as well as in control tissues known to expre ss GPX proteins (the liver for GPX1 and the kidney for GPX3), The 3 ge nes characterized to date were found expressed in each of the tissues tested but in a highly tissue-restricted manner. Nucleotidic sequences comparisons were carried out on GPX-encoding sequences from various s pecies and were used to draw a dendrogram. Phylogenetic evaluation of the sequence information, as well as the chromosomal localizations, su ggest that the GPX genes have evolved by duplication events followed b y random insertions from a single ancestral gene.