cAMP-dependent binding of a trans-acting factor to the thyroglobulin promoter.
We have investigated the interaction of a nuclear factor(s) with the promoter region of the thyroglobulin (Tg) gene, which is only expressed in differentiated thyroid cells under the positive control of the pituitary hormone thyrotropin (TSH) via a cAMP-dependent pathway. Using the mobility shift assay, we first demonstrated that a thyroid nuclear factor interacts with a short segment of 60 bp (-136 - -77) which is conserved among species in the regulatory region of the Tg gene. A specific binding site was then localized in a subfragment of 20 bp located between -126 bp and -107 bp relative to the transcription initiation site. The corresponding nuclear factor is absent in a tissue which does not express the Tg gene. This factor differs from previously identified factors shown to mediate a direct cAMP response since the observed binding is neither competed out by the cAMP responsive element (CRE) nor by the activator protein 2 (AP2) binding site. This trans-acting factor represents a new candidate intermediate in the regulation of transcription by a cAMP dependent mechanism.
Hansen
C
C
Institut de Recherche en Biologie Humaine et Nucléaire, Bruxelles, Belgium.
Javaux
F
F
Juvenal
G
G
Vassart
G
G
Christophe
D
D
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000302:isolation & purification*; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D013954:Thyroglobulin / Q000235:genetics* / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D014157:Transcription Factors; D013954:Thyroglobulin; D000242:Cyclic AMP