8.2.5 Regulation of Transcription

Regulation of Transcription and Translation: Control by Oestrogen

The hormone oestrogen plays a key role in regulating transcription by influencing molecules called transcription factors. These transcription factors bind to specific DNA sequences to initiate or regulate the transcription of genes.

Process of Transcription Regulation by Oestrogen

1. Diffusion of Oestrogen:

• Oestrogen is lipid-soluble, allowing it to freely diffuse through the phospholipid bilayer of the cell membrane.

2. Binding to Receptor:

• Once inside the cell, oestrogen binds to a specific receptor molecule on a transcription factor in the cytoplasm.

3. Activation of Transcription Factor:

• The binding of oestrogen causes a conformational change in the transcription factor, particularly in its DNA-binding site.
• This change enables the transcription factor to bind to DNA.

4. Entry into the Nucleus:

• The activated transcription factor moves into the nucleus via nuclear pores.

5. Stimulation of Transcription:

• Once inside the nucleus, the transcription factor binds to a specific region of DNA at the promoter site.

• This promotes the attachment of RNA polymerase, stimulating the transcription of the gene.

• Oestrogen controls transcription by activating transcription factors.

Importance of Oestrogen Regulation

• Tissue-specific transcription: Allows certain genes to be expressed in specific tissues, such as those in the reproductive system.
• Response to hormonal signals: Enables the body to adapt to changes in hormone levels.