What is the Origin of Thyroid Response Elements?

The concept of a response element is a foundational principle in molecular endocrinology, established through research that elucidated the intracellular mechanism of action for steroid and thyroid hormones. The identification of TREs provided the definitive molecular link between the circulating endocrine messenger and the resulting change in gene expression. This is a core mechanism of thyroid hormone action on a cellular level.

What is the Mechanism of Thyroid Response Elements?

The thyroid hormone receptor, typically forming a heterodimer with the Retinoid X Receptor (RXR), binds to the TRE in the cell nucleus. In the absence of T3, this receptor complex often acts as a repressor, suppressing gene transcription. Upon T3 binding, the receptor undergoes a critical conformational change, recruits co-activator proteins, and switches to an activator role, thereby initiating the transcription of genes responsible for metabolic regulation, growth, and development.

Thyroid Response Elements ∞ Area

Thyroid Response Elements

Meaning

Thyroid Response Elements (TREs) are specific, short DNA sequences located in the promoter regions of target genes that are regulated by thyroid hormones. These sequences serve as direct binding sites for the thyroid hormone receptor (TR), which, when bound to the active hormone triiodothyronine (T3), precisely modulates the rate of gene transcription. TREs are the molecular switches that translate the circulating hormonal signal into a change in cellular protein synthesis and function.