Immunofluorescence signals for GSTs
(Figs. 4A 4B 4C 4D)displayed a widespread expression in all anterior segment tissues of normal control eyes (
n = 5). Signals for both GSTT1 and mGST1 were found in almost all cell types, particularly in the vascular endothelia of the iris, conjunctiva, episclera, and ciliary body; signals in the ciliary epithelium were particularly pronounced along the tips of the ciliary processes. The levels of GSTT1 and mGST1 protein expression were generally weaker or hardly detectable in anterior segment tissues, particularly the iris, ciliary body, and trabecular meshwork, of all PEX eyes examined (
n = 5). Consistent with their known subcellular localization, signals for UBE2A/B indicated a ubiquitous but variable nuclear, perinuclear, or cytoplasmic localization in anterior segment tissues of normal eyes. Staining was most pronounced in epithelial, endothelial, stromal, and muscle cells of the iris and appeared markedly reduced in all PEX eyes examined
(Figs. 4E 4F) . Staining for MLH1 was exclusively nuclear and was seen in epithelial, endothelial, stromal, and muscle cells of the cornea, conjunctiva, trabecular meshwork, iris, and ciliary body. Nuclear signals for MLH1 were clearly weaker or hardly detectable in iris and ciliary body tissue of three of five PEX eyes
(Figs. 4G 4H) . Although GADD153 was not detectable by Western blot analysis and usually is expressed at low levels under normal conditions, a weak but distinct immunoreactivity was observed in many cell nuclei of the cornea, conjunctiva, trabecular meshwork, iris, and ciliary body of normal eyes, which showed marked interindividual differences in expression levels. The overall number of immunopositive cells was clearly diminished, however, in the iris and ciliary body of all PEX eyes examined
(Figs. 4I 4J) .