by Tom Williams, a Postdoc in the Rousseau group at the MRC-PPU, University of Dundee
Our bodies are made up of lots and lots of cells. I try to figure out how cells work so that we can fix them if they go wrong and cause a disease. To do this I use creatures you might find in soil or rotting fruit!
Why do I use these creatures to try and learn more about human disease? Well, humans are complicated. Really complicated. There are around 200 different types of cell in our bodies, each of which has over 20,000 genes. These genes contain the information to make over 80,000 proteins, and these proteins perform the tasks our body needs to stay alive.
Not every cell uses every gene or makes every protein. Several proteins do more-or-less the same jobs as each other. This helps protect our cells in case there are problems with one particular protein. Unfortunately, this can make it really difficult to figure out the job each protein does!
Enter model organisms. These are “simple” creatures with fewer genes. These genes themselves make fewer proteins, which means individual genes and proteins can be removed or deleted with less chance of there being other proteins to take over their jobs. This helps us work out the job performed by the protein made from that particular gene. When you take it away, what changes? If it makes the cell stop moving around, the protein is probably involved in cell movement. We can take what we learn as a guide for what similar proteins might do in our bodies.
Model organisms are different from humans but have some similar characteristics. Choosing the right organism to study depends on what you want to find out. C. elegans nematodes are tiny worms with a fully functioning nervous system. S. cerevisiae yeast have similar proteins that pass on messages telling the cell what to do as we do. D. discoideum amoebae move around and hunt bacteria like immune cells. Scientists have used each of these organisms to work out how cells can do certain things, which has helped work out how human cells do those things. This helps development of new medicines, as if we don’t know how the body works, we don’t know how to fix something that’s gone wrong!
So why use model organisms? If you want to build a skyscraper, first learn how to build a shed.
Tom Williams is a Postdoc in the Rousseau group at the MRC-PPU, University of Dundee. He uses model organisms to research how cells sense changes in the environment and react to them.