Question

What is a hormone response element?

Answer 1

Hormone-reponse element:

1. The hormone response element (HRE) is a short DNA sequence within the promoter of a gene that is capable of binding to specific hormone receptor complexes and regulating transcription.
2. This sequence is most commonly a pair of reverse repeats separated by three nucleotides and also shows that the receptor binds as a dimer.
3. Genes can have many different response elements, allowing complex control of the degree and rate of transcription.

Example: Steroid hormone receptors and their response elements:

1. Steroid hormone receptors are proteins that have binding sites for specific steroid molecules.
2. Those response elements are DNA sequences bound by a steroid complex bound to that receptor.
3. Receptor-mediated binding activates or optionally suppresses genes controlled by its promoter.
4. Through this mechanism, steroid hormones turn genes on/off.

Positive and negative response elements:

1. Some of the hundreds of glucocorticoid response elements in the human genome activate gene transcription when bound to the hormone/receptor complex.
2. Others inhibit gene transcription when bound to the hormone/receptor complex.
3. Example: When the stress hormone cortisol enters the nucleus of hepatocytes, the complex binds.
4. Positive response elements for many genes involved in gluconeogenesis-conversion of proteins and fats to glucose. This raises your blood sugar.
5. Therefore, the negative response element of the insulin receptor gene reduces the cell's ability to remove glucose from the blood.