甲状腺激素受体在调节靶基因转录中的激活和抑制作用

Transcriptional activation and repression regulation in target gene by thyroid hormone receptors

甲状腺激素((TH)在个体发育、维持内环境稳定、细胞增殖和分化方面均有广泛的作用。TH结合甲状腺激素受体(TR),包括TRα和TRβ。TR属于核激素受体超家族,调节正向和负向基因转录。在缺少配体时,TR结合特异DNA序列,通过和共抑制子相互作用主动抑制转录。配体的结合导致TR结构改变,释放共抑制子并招募共激活子而激活转录。

Thyroid hormones （THs） have extensive effects on ontogeny, maintaining homeostasis, cellular proliferation and differentiation. They bind to thyroid hormone receptors （TRs）, TRalpha and TRbeta, which belong to the nuclear hormone receptor superfamily. These receptors also bind to enhancer elements in the promoters of target genes, and can regulate both positive and negative transcription. Unliganded thyroid hormone receptor represses transcription through recruitment of a corepressor complex. Ligand binding alters the conformation of the thyroid hormone receptor in such a way as to release the corepressor complex and recruit a coactivator complex.