Lambotte S, Veyhl M, Köhler M, Morrison-Shetlar A I, Kinne R K, Schmid M, Koepsell H
Max-Planck Institute für Biochemie, Martinsried, Germany.
DNA Cell Biol. 1996 Sep;15(9):769-77. doi: 10.1089/dna.1996.15.769.
Recently, a cDNA (pRS1) was cloned from pig kidney cortex that encodes a membrane-associated protein involved in Na(+)-coupled sugar transport. pRS1 alters sugar transport by SGLT1 from rabbit intestine or by SMIT from dog kidney which is homologous to SGLT1. In contrast, pRS1 does not influence transporters from other genetic families. We report the cloning of the intronless human gene hRS1 (6,743 bp), which encodes a 617-amino-acid protein with 74% amino acid identity to pRS1. By fluorescence in situ hybridization, hRS1 was localized to chromosome 1p36.1. The localization to one chromosome and Southern blot analysis of restricted genomic DNA suggest that there is only one RS1-homologous gene in humans. Functionality of hRS1 was demonstrated by co-expression experiments of hRS1 and SGLT1 from human intestine in oocytes from Xenopus laevis. They show that hRS1-protein inhibits Na(+)-D-glucose co-transport expressed by human SGLT1 by decreasing both the Vmax and the apparent Km value of the transporter. The analysis of the 5'-noncoding sequence of hRS1 revealed different enhancer consensus sequences that are absent in the SGLT1 gene, e.g., several consensus sequences for steroid-binding proteins.
最近，从猪肾皮质克隆出一种互补DNA（pRS1），它编码一种参与钠偶联糖转运的膜相关蛋白。pRS1可改变兔小肠中SGLT1或与SGLT1同源的犬肾SMIT的糖转运。相比之下，pRS1不影响其他基因家族的转运体。我们报道了无内含子的人类基因hRS1（6743 bp）的克隆，它编码一种617个氨基酸的蛋白质，与pRS1的氨基酸同一性为74%。通过荧光原位杂交，hRS1定位于染色体1p36.1。定位于一条染色体以及对限制性基因组DNA的Southern印迹分析表明，人类中只有一个与RS1同源的基因。通过在非洲爪蟾卵母细胞中共表达hRS1和人小肠的SGLT1进行的实验证明了hRS1的功能。结果显示，hRS1蛋白通过降低转运体的Vmax和表观Km值，抑制人SGLT1所表达的钠 - D - 葡萄糖共转运。对hRS1的5' - 非编码序列的分析揭示了SGLT1基因中不存在的不同增强子共有序列，例如，几种类固醇结合蛋白的共有序列。
