Transposons, or jumping genes, were first discovered for their role in causing unusual colour patterns on corn cobs
In this episode we explore the world of transposons, or jumping genes: sequences of DNA that can cut- or copy-and-paste themselves from one place to another in our genome. Listen in on a chat with Orsolya Barabas from EMBL Heidelberg and Ramesh Pillai from EMBL Grenoble about the chaos that these genetic hoppers can inflict upon our cells, how we keep them under control, and why we have them at all.
First discovered for their role in causing unusual colour patterns on corn cobs, transposons are kept inactive in most human cells by tags that essentially tell the cellular machinery to leave those areas alone, and not copy them. But when eggs and sperm are being formed, those silencing marks are lifted. So in these cells, transposons could potentially jump around, insert themselves in the middle of a gene or other important stretch of DNA, for instance, and disrupt it. To prevent this – and the chaos that would surely ensue – egg and sperm cells have specific machinery for interfering with transposons and mopping up the copies they do produce before they’re inserted back into the genome.
Orsolya and Ramesh’s groups both study how this transposon-stopping machinery works, but they approach it from different angles. The Pillai group looks at what happens to mice and their cells when they interfere with different parts of this process, while the Barabas group looks at the 3-D structure of the molecules involved, and how they interact with each other. Combining these two approaches, the groups are able to bridge a variety of scales and get a comprehensive picture of the different steps of the process
In this podcast, Orsolya and Ramesh take a step back and look at an even bigger picture, discussing how we ended up carrying these genetic ‘parasites’ around, and why we haven’t got rid of them - as it turns out, they may have their uses.
- EMBLetcetera article on the Pillai group’s transposon work: 'How cells defend internal threats'
- The Barabas group’s discovery: how egg cells make their first batch of transposon-silencing protein
- Method developed by the Spitz group at EMBL Heidelberg: using a jumping gene to study gene regulation
- A jumping gene’s contribution to our own evolution, as discovered by the Flicek group at EBI