CLONING OF A FUNCTIONAL PROMOTER OF THE HUMAN SODIUM IODIDE-SYMPORTERGENE/

We have cloned and sequenced genomic DNA from a human library extendin g 1300 bp upstream the 5'-untranslated sequence of the cDNA coding for the sodium/iodide symporter. In transient transfection assays this se quence exhibited promoter activity, which could be confined to nucleot ides -443 to -395 relative to the ATG start codon. This minimal promot er, including a putative GC-and TATA-box, was preferentially activated in the rat thyroid cell line FRTL-5, but was also active in non-thyro idal cells, such as COS-7 and Chinese-hamster ovary, albeit to a marke dly lower extent.