Transcriptional regulation of the human calcitonin gene: a progress report.
We have applied DNA transfer techniques to study the transcriptional regulation of the calcitonin (CT) gene in a C-cell line (TT) derived from a human medullary thyroid carcinoma. TT cells were transfected with a fusion gene containing the CT gene promoter and 5'-flanking DNA attached to the promoter-less growth hormone gene (reporter). We quantitated the reporter gene product to monitor transcriptional activation by the CT promoter and deletion mutants of the 5'-flanking DNA. We found that the proximal CT promoter which includes the DNA sequence from +1 to -129 bp upstream from the CT transcription start site did not induce transcription in C-cells or in NIH 3T3 cells. The attachment of additional 5'-flanking DNA, extending up to -1460 bp enhanced transcription up to twelvefold in TT cells but had no effect on transcription in 3T3 cells. Deletion of a sequence located at -1290 to -820 bp on the CT 5'-flanking DNA abolished the transcription of the reporter gene. Attachment of the DNA sequence located between -1333 to -731 to the fusion gene, containing the CT promoter (+1 to -129) and the reporter gene, restored transcription of the reporter gene in TT cells. We conclude that an enhancer of CT transcription, which is active in C-cells but not in 3T3 cells, is located between -1290 and -820 of the CT 5'-flanking DNA.
Peleg
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Cote
G J
GJ
Abruzzese
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RV
Gagel
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D002116:Calcitonin / Q000235:genetics*; D002478:Cells, Cultured; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D066298:In Vitro Techniques; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014162:Transfection
D002116:Calcitonin