This image shows a 3-D reconstruction from electron tomograms of high pressure-frozen cells. Red: microtubules; green: 17 nm diameter filaments; blue: midbody; yellow: plasma membrane. This image relates to an article that appeared in the Feb. 10, 2011, issue of Science Express, published by AAAS. The study, by Dr. Julien Guizetti at Swiss Federal Institute of Technology Zurich (ETHZ) in Zurich, Switzerland, and colleagues was titled, “Cortical Constriction During Abscission Involves Helices Of ESCRT-III-Dependent Filaments.".

Biologists have studied cell division for decades, yet the mechanics of how cells physically separate from one another have remained largely a mystery. To better understand the mechanism, molecular cell biologist Daniel Gerlich of the Swiss Federal Institute of Technology, along with colleagues from Switzerland and Germany, scanned dividing cells at various angles with electron beams.

The scientists used that data to create a 3-D image of the intercellular bridge, the region where cells split in two. The image showed the cell’s internal skeleton, which includes microtubules [red], and also revealed previously unknown filaments [green] constricting the area where division occurs. Gerlich says that his next goal is to clarify the chemical composition of the mysterious filaments and the process by which they form.