The taurine transporter gene and its role in renal development

This paper examines a unique hypothesis regarding an important role for tau rine in renal development. Taurine-deficient neonatal kittens show renal de velopmental abnormalities, one of several lines of support for this specula tion. Adaptive regulation of the taurine transporter gene is critical in ma mmalian species because maintenance of adequate tissue levels of taurine is essential to the normal development of the retina and the central nervous system. Observations of the remarkable phenotypic similarity that exists be tween children with deletion of bands p25-pter of chromosome 3 and taurine- deficient kits led us to hypothesize that deletion of the renal taurine tra nsporter gene (TauT) might contribute to some features of the 3p-syndrome. Further, the renal taurine transporter gene is down-regulated by the tumor suppressor gene p53, and up-regulated by the Wilms tumor (WT-1) and early g rowth response-1 (EGR-1) genes. It has been demonstrated using WT-1 gene kn ockout mice that WT-1 is critical for normal renal development. In contrast , transgenic mice overexpressing the p53 gene have renal development defect s, including hypoplasia similar to that observed in the taurine-deficient k itten. This paper reviews evidence that altered expression of the renal tau rine transporter may result in reduced intracellular taurine content, which in turn may lead to abnormal cell volume regulation, cell death and, ultim ately, defective renal development.