The taurine transporter gene and its role in renal development.

This paper examines a unique hypothesis regarding an important role for taurine in renal development. Taurine-deficient neonatal kittens show renal developmental abnormalities, one of several lines of support for this speculation. Adaptive regulation of the taurine transporter gene is critical in mammalian 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 between children with deletion of bands p25-pter of chromosome 3 and taurine-deficient kits led us to hypothesize that deletion of the renal taurine transporter 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 growth response-1 (EGR-1) genes. It has been demonstrated using WT-1 gene knockout mice that WT-1 is critical for normal renal development. In contrast, transgenic mice overexpressing the p53 gene have renal development defects, including hypoplasia similar to that observed in the taurine-deficient kitten. This paper reviews evidence that altered expression of the renal taurine transporter may result in reduced intracellular taurine content, which in turn may lead to abnormal cell volume regulation, cell death and, ultimately, defective renal development.