Submitted by Matthew Daniels (Hutchison/Medical Research Council (MRC) Research Centre, Cambridge, UK (mjd46@hermes.cam.ac.uk)). When all chromosomes are attached to the spindle and under tension, they become arranged in a structure known as the metaphase plate. When two metaphase plates occur in a single cell, they become orientated perpendicularly to each other, seen here in the shape of an 'X'.

The image shows a three-dimensional reconstruction of a HeLa cell that was stained for actin (blue), kinetochores (green) and DNA (red). The image was obtained using a laser scanning microscope (Zeiss LSM 510 META), and was rendered using Zeiss LSM Image Browser Software. Bar, 5 μm