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Asked by to Claire, Ian, Sergey, Vicky, Zena on 18 Jun 2014. This question was also asked by , .
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Claire Shooter answered on 18 Jun 2014:
We were interested in how a particular receptor that was present on some nerve cells functioned.
The receptor is a little molecule on the surface of the cell which is exactly the right shape for a particular molecule, like a hormone or other signalling particle, to fit inside. When that molecule is around and binds with the receptor, the receptor starts a chemical reaction in the nerve cell which makes it fire an action potential.
To see which cells had the receptor we were interested in on them, we made an antibody that is the right shape to stick to the the receptor. We attached a fluorescent tag to the antibodies and then mixed the antibodies with the cells. We stick some of the cells to a microscope slide and then look at them under UV light, which makes the fluorescent tags glow. We can then see which cells light up and how much, which allows us to see which cells have the interesting receptor, and whereabouts on the cell and how many of them there are
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Ian Simpson answered on 18 Jun 2014:
I can answer this one too (if that’s OK !?)
We’ve done two experiments in recent years that make nerve cells glow green, but using a different approach to Claire.
In the first case we were studying a gene that is required for the normal development of the brain in mice. The gene is expressed at different times and at different places and we wanted to be able to specifically extract those cells from all the other brain cells so that we could see what properties they had. We also had some strains of mice that had specific defects in this gene and wanted to see what was different about those cells compared to the normal ones.
In our case we made a genetically modified mouse (called a transgenic mouse) where all of the cells that expressed our gene also expressed a protein called, Green Fluorescent Protein (GFP) which emits light in the green range when excited by a laser at the correct wavelength (it was originally discovered in Jelly Fish). We could dissect out material, separate the cells into a solution and then pass that solution through a special machine called a Fluorescence Activated Cell Sorter (FACS) which sorts the green cells into one tube and the non-green into another. We then looked at the genes that were expressed in those cells and learned a lot about what our gene of interest was doing.
In the second experiment we did almost exactly the same thing but in a fruit-fly and we were again interested in what genes were being expressed in a sub-set of cells that expressed a gene that was essential for the formation of sensory nerve cells. We did this in the fly because it is a very useful model organism that allows us to very rapidly perform experiments that would take many years and be much more complicated in a mouse.
Both of these research projects have added a huge amount to what we know about how neural structures are formed and some of the key control genes that direct the very complicated process of building brains. Mutations in all of the genes that we worked with here are responsible for serious neurological diseases in people and we believe that what we learned from these experiments has taken us a step closer to understanding what has gone wrong. The ultimate hope is that as we learn more about the processes involved in building a brain we will identify ways to intervene, preventing or alleviating the symptoms of the resulting diseases in people.
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