Thyroid hormone dependent gene expression

The presented work is destined to review the advances that had been made to study the role of thyroid hormone and thyroid hormone nuclear receptors in regulating the gene expression. Triiodothyronine (T3) and tetraiodothyronine (thyroxine or T4) are most important thyroid hormones. The thyroid hormones bind to their specific nuclear hormone receptors, as ligand, and play important role in gene expression and transcriptional gene regulation in human and higher animals. Thyroid hormone receptors form heterodimers by making combination with retinoid X receptors. The capability of heterodimerization of thyroid hormones generates novel complexes which allow altered specificity and higher affinity for DNA-receptor binding. Thyroid hormone receptors work as ligand activated transcription factor and play with transcriptional gene expression process. The consensus structural features of thyroid hormone receptors are N-terminal regulatory domain that contains activation function, the domain for strong gene expression and the domain for binding to DNA. The structures for individual domains have been extensively and reviewed through several latest and successful techniques.