Berry G T, Mallee J J, Kwon H M, Rim J S, Mulla W R, Muenke M, Spinner N B
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, USA.
Genomics. 1995 Jan 20;25(2):507-13. doi: 10.1016/0888-7543(95)80052-n.
A human Na+/myo-inositol cotransporter (SLC5A3) gene was cloned; sequencing revealed a single intron-free open reading frame of 2157 nucleotides. Containing 718 amino acid residues, the predicted protein is highly homologous to the product of the canine osmoregulatory SLC5A3 gene. The SLC5A3 protein is number 3 of the solute carrier family 5 and was previously designated SMIT. Using fluorescence in situ hybridization, the human SLC5A3 gene was localized to band q22 on chromosome 21. Many tissues including brain demonstrate gene expression. The inability of a trisomic 21 cell to downregulate expression of three copies of this osmoregulatory gene could result in increased flux of both myo-inositol and Na+ across the plasma membrane. The potential consequences include perturbations in the cell membrane potential and tissue osmolyte levels. The SLC5A3 gene may play a role in the pathogenesis of Down syndrome.
克隆了一个人类钠/肌醇共转运体（SLC5A3）基因；测序显示有一个2157个核苷酸的无内含子单一开放阅读框。预测的蛋白质含有718个氨基酸残基，与犬类渗透调节性SLC5A3基因的产物高度同源。SLC5A3蛋白是溶质载体家族5的第3号成员，以前被命名为SMIT。利用荧光原位杂交技术，将人类SLC5A3基因定位到21号染色体的q22带。包括脑在内的许多组织都有该基因表达。21三体细胞无法下调该渗透调节基因三个拷贝的表达，可能导致肌醇和钠离子穿过质膜的通量增加。潜在后果包括细胞膜电位和组织渗透溶质水平的紊乱。SLC5A3基因可能在唐氏综合征的发病机制中起作用。
