Endowing cells with a magnetic personality

By Robert Sanders

BERKELEY -- Some bacteria make their own tiny magnets to navigate the oceans. But these tiny compasses also show up beautifully in 3-D magnetic resonance imaging (MRI) scans, inspiring UC Berkeley scientists to use them to track the movement of cells in the body or molecules within cells.

Magnetotactic bacteria make their own tiny bar magnets (black dots) and use them to navigate the globe. Since they show up well on MRI scans, they should make a great tag for following cells in the body or molecules inside a cell (Courtesy of Komeili lab

Researchers today label genes or proteins with green fluorescent protein (GFP) – a development honored in 2008 with a Nobel Prize. But GFP is only useful for looking at cells on the body surface or inside transparent embryos. With a $1 million high-risk, high-reward grant from the W. M. Keck Foundation, the team plans to implant the relevant genes from magnetotactic bacteria into mammalian cells so they can make their own magnets. Mikhail Shapiro, one of the project’s leaders, says the technique will help scientists explore how tumors spread, immune cells find pathogens or brain cells degenerate.