Beron, Celia, Khalil, Moe, Bainbridge, Chance, Boutz, Daniel, Rickert, Trevor, Gokce, Sertan, Ghoashian, Navid, Ward, Kristi, Marcotte, Edward, Pierce-Shimomura, Jonathan, Papoulas, Ophelia, Ben-Yakar, Adela, Vidal-Gadea, Andres
[
International Worm Meeting,
2015]
A wide range of organisms use the earth's magnetic field to orient. Much of our understanding about the molecular basis for this behavior comes from work on magnetotactic bacteria. These organisms build nanometer-sized "compasses" from magnetic iron extracted from their environment. Evidence of similar biological magnetite has been reported in many magnetotactic animals (including C. elegans). It remains unclear if and how animals may use these "biological compasses" in this exciting form of sensory transduction. We have recently found that C. elegans readily orients to the magnetic field of the earth in a way that is consistent with a magnetite-based mechanism. Worms appear to use the magnetic field during vertical migrations using an identified a pair of sensory neurons. These neurons are required for magnetotaxis and respond cell-autonomously to earth-strength magnetic fields in calcium imaging experiments. We are attempting to identify the molecular machinery responsible for magnetotransduction using complementary biochemical, genetic and physiological approaches. To determine proteins associated with a hypothetical "worm compass", we performed mass spectrometry on iron particles isolated from C. elegans. Next, to determine whether these proteins are required for magnetotaxis, we assayed the magnetotactic ability of the corresponding mutants. For the subset of mutants that display defective magnetotaxis, we are analyzing the subcellular localization of their respective proteins near candidate compass structures. In parallel, we are testing the requirement of these genes in physiological responses to magnetic fields via calcium imaging. The genetic and behavioral tractability of C. elegans makes this a promising model for elucidating potentially conserved mechanisms by which many animals detect and orient to magnetic fields. .