Regulation of Transcription & Translation

This lesson covers: 

1. What transcription factors are
2. Hormonal control of transcription

What are transcription factors?

Transcription factors are proteins that bind to specific DNA sequences to initiate the transcription of genes into mRNA.

mRNA is that is produced during transcription then carries the genetic code from DNA to ribosomes, allowing the production of proteins. Transcription factors therefore have a crucial role in gene expression regulation.

When a gene is 'switched off', transcription factors cannot bind to DNA. This prevents the transcription process and so the synthesis of polypeptides.

Hormonal control of transcription

Steroid hormones, such as oestrogen, can regulate transcription.

They do this through a series of steps:

1. Steroid hormones diffuse through the cell-surface membrane into the cell.
2. Inside the cell, these hormones bind to receptors on transcription factors.
3. This binding changes the shape of the transcription factor, activating it.
4. The activated transcription factor then enters the nucleus and binds to specific DNA sequences.
5. This binding stimulates the transcription of the gene located at these sequences.