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May 24, 2016

NSF grant will help decipher cells’ electric properties

A Michigan State University researcher will use a National Science Foundation grant to decipher the secrets of electric organs in fish and apply the insights to human electrically excitable tissue.

The grant is being split between two universities. Jason Gallant, MSU integrative biologist, will receive $300,000, and Harold Zakon with the University of Texas also will be awarded approximately $300,000. The two labs will collaborate to see how fish that developed extra genomic material millions of years ago can teach us humans.

Our nervous system, heart and muscles need two types of proteins, called ion channels, to produce electrical pulses – sodium and potassium channels. The researchers will focus on the role that the genes, which allow ions to move through cell membranes and conduct electricity, play.

Gallant helped lead earlier research that sequenced the electric eel genome and is currently sequencing the genome of the African electric fish. Genome studies of electric fish have revealed how the diversity of their brief electrical pulses result from the activity of ion channels.

Because fish experienced an ancient duplication of their entire genome millions of years ago, non-electric fish have two copies of each ion channel in their muscles compared to humans. Electric fish use this “extra” set of ion channel genes to evolve new tissue – an electric organ. The evolutionary trait has helped them thrive in many different types of habitats.

“We know that electric fishes produce astonishingly brief electrical pulses, and that potassium and sodium channels have experienced mutational changes that may allow these channels to operate much faster than their muscle counterparts,” Gallant said. “We will sequence the potassium channel gene from many fish to try to identify exactly what ‘letter’ of the DNA makes a fast or slow channel.”

For the fishes, little changes in the potassium channel have the potential to create a new signal. And because the fishes use signals to determine mating, alterations can cause disruptions in populations or could lead to new species, which is a central focus of Gallant’s laboratory.

In humans, the work is important because it could offer greater insight into the role that genetic changes play in determining electrical properties of all types of cells including heart, brain and muscle cells. Many of the mutations in ion channel genes that cause rapid movement of current in electric organs occur at the same positions of their human counterparts, where they cause heritable diseases of the nervous system.

“It’s amazing to think that by changing a few ‘letters’ in the genetic code that you might be able to get the nervous system or electric organ to sing a different tune,” Gallant said.

By: Layne Cameron