Pulling into Place

Chromosomes need to be properly aligned before they can be pulled apart. Each panel in this picture shows how DNA (stained purple) within chromosomes tries to align in the centre of a cell ready for division. Over time, (time flows from top to bottom) the chromosomes in the left panel are tugged back and forth around a spindle [structure that helps anchor chromosomes] by a protein called dynein (shown in white). Eventually this oscillation slows down and the DNA lines up in the right place. Scientists changed spindle oscillations by either blocking the activity of dynein (second panel) or adding a drug to hamper spindle activity (third and fourth panels). Understanding how to stop cells from dividing paves the way for halting the growth of tumours.

Written by John Ankers

• Tomomi Kiyomitsu
• Whitehead Institute for Biomedical Research, USA
• Reprinted by permission from Macmillan Publishers Ltd: Nature Cell Biology, Copyright 2012
• Published in Nature Cell Biology