Transfection of calcitonin gene regulatory elements into a cell culture model of the C cell.

Abstract

Calcitonin gene expression in the TT cell line can be regulated by phorbol esters, cAMP, glucocorticoids, and 1,25-dihydroxyvitamin D3. To further study the regulation of this gene we have sequenced 1460 bases 5' to the start of calcitonin gene transcription. This DNA sequence contains cis consensus elements for both phorbol ester- and cAMP-responsive elements. To study the role of these elements, calcitonin 5' flanking DNA was coupled to the human growth hormone gene as a reporter and transiently transfected into TT cells, a human thyroid C cell line. Treatment of transfected TT cells stimulated a two- to fivefold increase in reported gene product expression, confirming the existence of functional cAMP- and phorbol ester-dependent enhancers within the calcitonin 5' flanking sequence.