Endowing Cells With a Magnetic Personality

Some bacteria make their own magnets in order to navigate aquatic environments. 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.

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, a team of Berkeley researchers that includes Arash Komeili, an associate professor of plant and microbial biology, plans to implant the relevant genes from magnetotactic bacteria into mammalian cells so they can make their own magnets. Mikhail Shapiro, a researcher affiliated with the Departments of Bioengineering and Molecular and Cell Biology, and one of the project’s leaders, said the technique will help scientists explore how tumors spread, immune cells find pathogens, and brain cells degenerate.

“If we can transplant the genetic machinery that makes these strong and beautifully magnetic structures into mammalian cells, you would fulfill the dream of a magnetic, noninvasive version of GFP that allows really sensitive imaging of gene expression,” he said.

Watch magnetotactic bacteria as they are forced to swim to the edge of a water droplet with a bar magnet.
Video, including still, above, by Meghan Byrne, formerly a researcher in the Komeili lab.