Skip main navigation
We use cookies to give you a better experience, if that’s ok you can close this message and carry on browsing. For more info read our cookies policy.
We use cookies to give you a better experience. Carry on browsing if you're happy with this, or read our cookies policy for more information.

Regulation of gene expression

All the cells of our body contain identical genes.

However, the cells of our muscles look different and fulfill very different functions to, for example, the cells of our eye. So how is this possible? The answer is that not all the ≅20 000 genes are expressed or “switched on” in every cell: specific genes are expressed at specific times in specific cells.

The control of gene expression is highly complex and a detailed description is beyond the scope of this course. However, in order to provide you with a flavour of this carefully orchestrated system, we will briefly consider three mechanisms which contribute to the regulation of gene expression:

Epigenetic regulation

The epigenome plays a critical role in the regulation of gene expression both through direct modification of DNA (such as DNA methylation) or through chromatin remodelling (how tightly the DNA is wrapped around the histone proteins). We won’t spend a great deal of time on the epigenome in this step as we have explored it in an earlier step.

The production of transcription factors

Transcription factors form complexes and bind to the promoters of genes to initiate transcription. Some components of the transcription complex are always present in cells whilst others are only formed in response to specific stimuli enabling cells to respond to changes in their environment and take on specific/targeted roles.

The regulation of protein production

The central dogma describes how DNA encodes RNA which in turn determines the type and order of the constituent amino acids of a protein. Given that it is the different proteins which determine a cell’s characteristics, regulation of protein production, and in particular transcription, is key to the regulation of gene expression.

Diagram of gene expression Diagram of gene expression Click to expand
© St George’s, University of London

Talking point:

The control of gene expression is really complex and difficult to understand. I sometimes find it helps to use an analogy to help visualise what is going on. For me, the analogy I use is starting and driving a car. The genome is the fully formed car. The epigenetic signal is the switch which causes a whole load of mechanical things to spring into action (as you can tell, I’m no car mechanic!) including the delivery of petrol to the engine (analagous to the transcription factors). These then cause the engine to turn (transcription) and the car can be driven (gene expression).

Can you think of another or better analogy?

Share this article:

This article is from the free online course:

The Genomics Era: the Future of Genetics in Medicine

St George's, University of London

Get a taste of this course

Find out what this course is like by previewing some of the course steps before you join:

  • Welcome to Week 1
    Welcome to Week 1

    In this video, Lead Educator, Dr Kate Tatton-Brown welcomes learners to the course and explains the course aims and outcomes.

  • Did you know?
    Did you know?

    Our resident scientist tells you his favourite genomics facts.

  • Errors in recombination
    Errors in recombination

    This video describes how structural chromosome abnormalities occur when errors occur in recombination.

  • Responsibility in the genomic era
    Responsibility in the genomic era

    In this tutorial, you will hear from Dr Carwyn Rhys Hooper on the concept of responsibility for health.

Contact FutureLearn for Support