University of Otago Associate Professor Tony Poole has spent decades investigating how the primary cilium works. He tells us how electron tomography has enabled him to build a 3D model of the primary cilium.
Associate Professor Tony Poole
Tomography allows you to see more material in greater detail and in a better three-dimensional way. The primary cilium is a very tiny organelle. It’s 200 nanometres thick, and it can be about a micron or two long, so it’s a very thin sort of long structure. And this makes them impossible to see in a light microscope, virtually impossible. Even in an electron microscope, you have to hunt to find them.
With normal electron microscopy, you cut very, very thin sections – about 80–90 nanometres. With electron tomography, you can cut much thicker sections, more 300–500 nanometres. This means you can get the entire cilium in one single section.
Once you’ve generated that dataset, you can turn it upside down and look at it from this end, you can turn it end on, you can zoom in, you can zoom out, you can do a huge amount but you’re not cutting any more sections. You’ve only cut one single section, and the way the tomographic dataset works, it allows you to then take very, very thin slices through your dataset – thinner slices than you could cut and look at in a conventional microscope.
It’s the first time we’ve ever been able to look, at very, very high magnifications, at the relationship between this primary cilium and the environment that it interacts with.
Associate Professor Tony Poole, University of Otago
Mike Jennings, University of Otago