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Functional role of TTF‐1 binding sites in bovine thyroglobulin promoter
Author(s) -
Javaux Françoise,
Bertaux Fabien,
Donda Alena,
Francis-Lang Helen,
Vassart Gilbert,
DiLauro Roberto,
Christophe Daniel
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80850-g
Subject(s) - thyroglobulin , microbiology and biotechnology , mutant , promoter , binding site , promoter activity , chemistry , footprinting , gene , gene expression , transcription factor , biology , biochemistry , thyroid , genetics
We have studied the binding of purified TTF‐1 on the bovine thyroglobulin gene promoter. DNase I footprinting experiments revealed three binding sites which corresponded in location to the A, B and C sites found in the rat thyroglobulin promoter. Mutants in the A and C regions showing reduced binding of TTF‐1, also exhibited largely decreased promoter activity in transient expression experiments in primary‐cultured dog thyrocytes. Two mutants in the B site that exhibited a reduced capacity to bind TTF‐1 also displayed a drastically affected transcriptional activity in transient assays. As in the rat, sites A and C only are critical for promoter activity, these results suggest that full occupancy of the B site is required for thyroglobulin promoter activity in the cow only.