We use the fruit fly to study
Stem cell competition
Stem cells have a social life and interact with other cells around them. They need support cells, which make up what's known as the niche, to provide them with signals in order to remain stem cells. We now know that each stem cell is in constant competition with neighbouring stem cells for those niche signals. The winner stays in contact with the niche, while the loser is pushed out and doesn't give rise to any more stem cells. Therefore, in order to contribute to tissues in the long term, stem cells need to be good at competing for space in the niche.
We use a combination of genetics, live imaging, mathematical modelling and genomics approaches to understand what makes one stem cell able to compete with its neighbours.
We focus on several related questions :
- How do stem cells interpret the signals they receive from the niche to become more or less competitive ?
- These signals act by making stem cells divide faster. How does the rate of cell cycle progression affect the competitive ability of a stem cell ?
- As well as niche signals, there are signals that make stem cells more likely to differentiate. We investigate how a single cell chooses to differentiate, and what changes happen within that cell as it leaves the niche.
Why the Drosophila testis ?
The fruit fly testis is an ideal model system : all the stem cells as well as the niche can be identified using their position. There are two stem cell populations, germline (which give rise to sperm) and somatic cyst stem cells (CySCs), which give rise to support cells for germ cell development. We focus on CySCs. We know many signals that control the self-renewal and competitive abilities of stem cells, and have unparalleled tools to genetically modify and track single stem cells so we can see how they behave over time.
We hope to make important findings that will advance our understanding of how stem cells compete for space in the niche using the fly.
Competition, though, isn't restricted to flies, it happens among many stem cells, in mice and in humans, and is controlled by the same genes and signals as the ones we study in flies. Therefore, by using all the tools and advantages of fly research, we will understand better how our own stem cells work.