How do hormones regulate gene expression?

Hormones regulate gene expression by binding to specific receptors and activating or repressing transcription factors.

Hormones are signalling molecules that are produced by endocrine glands and travel through the bloodstream to target cells. Once a hormone reaches its target cell, it binds to a specific receptor protein on the cell surface or inside the cell. This binding activates a signalling pathway that ultimately leads to changes in gene expression.

One way that hormones regulate gene expression is by activating transcription factors. Transcription factors are proteins that bind to DNA and control the rate of transcription, which is the process of copying DNA into RNA. Hormones can activate or repress transcription factors by binding to their receptors and triggering a cascade of signalling events that ultimately affect the transcription factor's activity.

Another way that hormones regulate gene expression is by altering chromatin structure. Chromatin is the complex of DNA and proteins that make up chromosomes. The structure of chromatin can either promote or inhibit gene expression, depending on how tightly the DNA is packed. Hormones can affect chromatin structure by recruiting enzymes that add or remove chemical groups from the histone proteins that package DNA. These modifications can either loosen or tighten the chromatin, making it more or less accessible to transcription factors.

In summary, hormones regulate gene expression by binding to specific receptors and activating or repressing transcription factors, as well as by altering chromatin structure. These mechanisms allow hormones to control a wide range of physiological processes, from growth and development to metabolism and behaviour.