Astriking photograph in a cell biology text convinced Ron Milligan (now at the Scripps Research Institute, La Jolla, CA) to take a closer look at the nuclear pore complex, the portal that ships materials back and forth across the nuclear membrane. The shot was the first he'd seen that clearly showed the pore's eightfold symmetry, with structures radiating from the center like petals of a flower, recalls Milligan, then a lab technician with Nigel Unwin's group at the Medical Research Council in Cambridge, UK. Apart from this detail, researchers knew little about the pore's architecture, except that it was a cylinder that sat in a hole spanning the two nuclear membranes, says Milligan. He and Unwin agreed that sophisticated image processing techniques might sharpen this hazy understanding.
They zoomed in on pores—some still embedded in the nuclear membrane and others that they had broken free—using...
