Elucidation of molecular pathophysiology and development of the methods for molecular diagnosis of the disease associated with WFS1 gene mutations.

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Wolfram (DIDMOAD) syndrome is an autosomal recessive disorder accompanied by juvenile-onset insulin-dependent diabetes mellitus and progressive optic atrophy. We recently identified the WFS1 (Wolfram syndrome 1) gene, a novel gene of unknown function. In this study, we generated a specific antibody against the COOH terminus of the WFS1 protein and investigated its subcellular localization in cultured cells. We also studied its distributions in rat brain. Biochemical studies indicated the WFS1 protein to be an integral, endoglycosidase H-sensitive membrane glycoprotein that localizes primarily in the endoplasmic reticulum. Consistent with this, immunofluorescence cell staining of WFS1 showed a characteristic reticular pattern over the cytoplasm and nuclear envelope. No evidence of co-localization of WFS1 with mitochondria was obtained, arguing against an earlier clinical hypothesis that Wolfram syndrome is a mitochondria-mediated disorder. In rat brain, WFS1 was found to be present pred … More ominantly in selected neurons in the hippocampus CA1, amygdaloid areas, olfactory tubercle and superficial layer of the allocortex. These expression sites, that is, components of the limbic system or structures closely associated with this system, may be involved in the psychiatric, behavioral and emotional abnormalities characteristic of this syndrome. ER localization of WFS1 suggests this protein to play as yet undefined roles in membrane trafficking, protein processing, and/or regulation of ER calcium homeostasis.As a step to elucidate the function of WFS1, we created a WFS1 -/- mice. In addition, we established WFS1 -/- mouse embryonic fibroblast from these mice. The studies for understanding the roles of WFS1 are being undertaken at whole body (mice) and cellular levels.We also studied the possible involvement of WFS1 gene mutations in the development of type 1 diabetes mellitus. We screened for the mutations in 21 Japanese patients with non-immune type 1 diabetes mellitus. Several nucleotide substitutions (single nucleotide polymorphisms) were identified without obvious association with this form of diabetes. Less