For
migratory birds and sea turtles, the ability to sense the Earth’s
magnetic field is crucial to navigating the long-distance voyages these
animals undertake during migration. Humans, however, are widely assumed
not to have an innate magnetic sense. Research published in Nature
Communications this week by faculty at the University of Massachusetts
Medical School shows that a protein expressed in the human retina can
sense magnetic fields when implanted into Drosophila, reopening an area
of sensory biology in humans for further exploration.
In
many migratory animals, the light-sensitive chemical reactions
involving the flavoprotein cryptochrome (CRY) are thought to play an
important role in the ability to sense the Earth’s magnetic field. In
the case of Drosophila, previous studies from the Reppert laboratory (http://reppertlab.org/) have shown that the cryptochrome protein found in these flies can function as a light-dependent magnetic sensor.
To
test whether the human cryptochrome 2 protein (hCRY2) has a similar
magnetic sensory ability, Steven Reppert, MD, the Higgins Family
Professor of Neuroscience and chair and professor of neurobiology,
graduate student Lauren Foley, and Robert Gegear, PhD, a post doctoral
fellow in the Reppert lab now an assistant professor of biology and
biotechnology at Worcester Polytechnic Institute, created a transgenic
Drosophila model lacking its native cryptochrome protein but expressing
hCRY2 instead. Using a behavioral system Reppert’s group previously
developed, they showed that these transgenic flies were able to sense
and respond to an electric-coil-generated magnetic field and do so in a
light-dependent manner.
These
findings demonstrate that hCRY2 has the molecular capability to
function in a magnetic sensing system and may pave the way for further
investigation into human magnetoreception. “Additional research on
magneto sensitivity in humans at the behavioral level, with particular
emphasis on the influence of magnetic field on visual function, rather
than non-visual navigation, would be informative,” wrote Reppert and his
colleagues in the study.
