A mutation in peroxidasin causes microphalmia and anterior segment dysgenesis in mice

Purpose The purpose of this study was to analyze the phenotype of ENU induced Pxdn-/- eyes in mice(KTA48 mutants) and investigate the molecular mechanisms of peroxidasin in eye development and disease. Methods The eyes of the mutants were analyzed by morphologically and histologically. The molecular expression was measured by immunofluorescence, in situ hybridization and real time PCR. Results The genome-wide linkage analysis mapped the KTA48 mutation on chromosome 12; positional candidate gene analysis detected a mutation in the Pxdn gene (encoding peroxidasin) co-segregating with the mutation. The Pxdn-mRNA of the KTA48 mutants contains a T->A mutation at pos. 3816 (T3816A) creating a new Alw26I restriction site; the mutation converts the Cys at codon 1272 into a stop codon (Cys1272X).Whole mount immunostaining showed that peroxidasin is mainly expressed in the eye at E9.5. Immunostaining study showed peroxidasin is mainly express in the eye lids, developing cornea, lens, inner retina at embryonic stages. At E15.5, the phenotype of the homozygous mutant is most obvious but varies little, with its different tissues (especially anterior segment) severely impaired. At P11 Pxdn-/- mice showed further anomalies in addition to the phenotype in embryonic eyes, including congenital corneal opacity, congenital cataract and congenital glaucoma. Real-time PCR showed the expression of Pax6 is dramatically increased at E15.5 Pxdn-/- eyes compared to wild-type eyes, which was confirmed by immunofluorescence and in-situ hybridization. Conclusion Our findings demonstrate a requirement for peroxidasin in normal eye development, which may be through regulating Pax6 expression.