Ryu K Y, Tong Q, Jhiang S M
Department of Physiology, Ohio State University, Columbus 43210, USA.
J Clin Endocrinol Metab. 1998 Sep;83(9):3247-51. doi: 10.1210/jcem.83.9.5118.
The Na+/I- symporter (NIS) is the plasma membrane protein that mediates active iodide uptake into thyroid follicular cells. To understand the molecular mechanisms of human NIS (hNIS) gene regulation, the 2-kb immediate 5'-flanking region of hNIS was characterized. The tentative hNIS transcriptional start site was mapped to -375 nucleotide relative to the ATG site. Various 5'-genomic DNA fragments were tested for promoter activity in thyroid and nonthyroid cells. Our results indicate that the DNA regulatory elements in the 2-kb immediate 5'-flanking region were not sufficient to confer thyroid-selective transcription of the hNIS gene. In addition, hNIS minimal promoter was localized to a region of 144 bp that contains a 90-bp stretch of a highly conserved DNA fragment between hNIS and rat NIS.
钠/碘同向转运体（NIS）是一种质膜蛋白，可介导碘离子主动摄取进入甲状腺滤泡细胞。为了解人NIS（hNIS）基因调控的分子机制，对hNIS基因5'端紧邻的2 kb侧翼区域进行了特征分析。暂定的hNIS转录起始位点相对于ATG位点定位于 -375核苷酸处。对各种5'基因组DNA片段进行了甲状腺细胞和非甲状腺细胞中的启动子活性测试。我们的结果表明，2 kb紧邻的5'侧翼区域中的DNA调控元件不足以赋予hNIS基因甲状腺选择性转录。此外，hNIS最小启动子定位于一个144 bp的区域，该区域包含hNIS和大鼠NIS之间一段90 bp高度保守的DNA片段。
