Promoter characterization of the rat Na+/I- symporter gene.
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.
Tong
Q
Q
Department of Physiology, Ohio State University, Columbus 43210, USA.
Ryu
K Y
KY
Jhiang
S M
SM
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002460:Cell Line; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000378:metabolism; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011989:Receptors, Thyrotropin / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D027981:Symporters; D013961:Thyroid Gland / Q000378:metabolism; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D000099209:Sodium-Iodide Symporters
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors; D012333:RNA, Messenger; D011989:Receptors, Thyrotropin; D012097:Repressor Proteins; D027981:Symporters; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D000099209:Sodium-Iodide Symporters; C106894:FOXE1 protein, human; C499496:Pax8 protein, mouse; C499497:Pax8 protein, rat