Abstract
The Na+/I- symporter is the molecule that mediates active iodide uptake in the thyroid gland. A 16.4 kb genomic DNA fragment of the rat Na+/I- symporter gene (rNIS) was isolated, restriction mapped and a 2 kb region immediate 5' to the ATG site was sequenced. The transcription start site for rNIS was mapped to -98 nucleotide (nt) relative to the ATG translation initiation site. A series of 5' genomic DNA fragments ranging from 233 bp to 8 kb were tested for promoter activity in both thyroid and non-thyroid cells. Our results indicate that the DNA regulatory elements within 8 kb of the 5' flanking region of rNIS are not sufficient to confer thyroid-selective transcription. However, consistent with the clinical observation that NIS expression is reduced in thyroid tumors, the rNIS promoter activity is suppressed in ret/PTC1 transformed NIH3T3 cells, compared to non-transformed NIH3T3 cells.
Original language | English |
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Pages (from-to) | 34-41 |
Number of pages | 8 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 239 |
Issue number | 1 |
DOIs | |
State | Published - 9 Oct 1997 |