The gears that help cells divide are coming into clearer focus. Researchers have used a new type of super-resolution microscopy to zoom in on centrosomes, which anchor the fibers that enable chromosomes to separate during cell division. Centrosomes have intrigued scientists since their discovery in the late 1800s, in part because cancer cells often amass extra copies of the structures. But they’re so tiny that they’re barely visible through traditional light microscopes, and researchers haven’t nailed down how they form and what role they play in cancer. So cell biologist David Glover of the University of Cambridge in the United Kingdom and his postdoc Jingyan Fu turned to three-dimensional structured illumination microscopy to provide sharper portraits of centrosomes  and to pinpoint several proteins they harbor. Each centrosome consists of two cylindrical components called centrioles shrouded by a molecular cloud, which balloons when cells start the process of division. As the team reveals online today in Open Biology, many of the cloud proteins first gather on the centrioles, moving into the cloud once division begins. That’s the case with the protein Cnn (green), shown above close to the cylindrical centriole (top) and dispersed in the cloud (bottom, inset). With further research, scientists might be able to determine how different proteins interact to construct centrosomes. “We can put the molecular jigsaw together,” Glover says.
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