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Updated: Jun 16, 2026

In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
Published on: October 6, 2023
The effect of hydroxylated polychlorinated biphenyl (OH-PCB) on thyroid hormone receptor (TR)-mediated transcription
Izuki Amano1, Wataru Miyazaki, Toshiharu Iwasaki
1Department of Integrative Physiology, Gunma University Graduate School of Medicine, Gunma 371-8511, Japan.
Abstract:
Polychlorinated biphenyls (PCBs) are known as environmental contaminants that may cause abnormal effect in various organs. We have previously reported that low dose of hydroxylated PCBs (OH-PCBs) including 4'-OH-2',3,3',4',5'-pentachloro biphenyl (4'-OH-PCB 106), suppressed thyroid hormone (TH) receptor (TR)-mediated transcription on several artificial TH-response elements (TREs) due to partial dissociation of TR from TRE. In the present study, we examined the effect of OH-PCB on TR-mediated transcription on native TRE-containing promoter, using malic enzyme (ME)-TRE. Transcriptional activity was measured by transient transfection based reporter gene assay in CV-1, fibroblast-derived clonal cells. TR-mediated transcription was suppressed by 4'-OH-PCB106 significantly and 4'-OH-PCB187 weakly, but not by 4'-OH-PCB165. To examine TR-TRE bindings under exposure of 4'-OH-PCB106, electrophoretic mobility shift assay (EMSA) was performed. In EMSA, TR was dissociated from ME-TRE by 4'-OH-PCB106. These findings suggest that OH-PCB may disrupt TR-mediated transcription on native promoter.
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