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In Living Color

Cancer researcher Jonathan Horowitz works with rodents, zebrafish and mammalian cells. But during countless hours at the microscope, he’s grateful for the humble jellyfish.

The gene that gives the crystal jelly its blue glow has illuminated Horowitz’s work and inspired a rainbow of tools for biomedical research.

“We rely on tools from bioluminescent organisms to answer some of our very fundamental questions,” says Horowitz, an associate professor of oncology in the College of Veterinary Medicine. “Not only are they useful for scientific information but they’re beautiful to work with.”

If I Only Had a Brain

People have always been fascinated with creatures that make their own light, from common fireflies to mysterious deep-sea creatures. Although biologists published a description of bioluminescence in 1955, the jellyfish’s glow gene wasn’t isolated until 1992.

The 2008 Nobel Prize in chemistry went to three scientists responsible for cloning green fluorescent protein (GFP) from the crystal jellyfish and adapting it for research. GFP, derived from a gelatinous creature that lacks a brain, quickly became a staple in cellular biology and cancer labs.

Dr. Jonathan Horowitz draws on a rainbow of glowing tools for cancer research
Dr. Jonathan Horowitz draws on a rainbow of glowing tools for cancer research, as this image shows.

The colorful genetic markers allow Horowitz to pinpoint a protein’s neighborhood, find out where it goes and see if its location overlaps with another protein’s ZIP code.

Scientists can draw from a varied palette to create original and sophisticated experiments. Neurological research, for example has produced breathtaking “brainbow” photos of nerve cells that make up a cellular switchboard.

“Follow the Red Bouncing Balls”

Horowitz used a glowing red marker in his research with transgenic zebrafish, tracking a gene as the fish grew from embroyos to adults. Through the third day of life, all of the zebrafish cells gave off a red glow when exposed to ultraviolet light, showing the gene’s presence.

“Subsequently, the lights turn out,” Horowitz says. “They get dimmer and dimmer, except in the kidneys, where they glow for another couple of days.

“In the adults, there’s no red, except in the girls, whose ovaries are bright red. The mom zebrafish (and we assume mice and humans) pack their eggs with our gene of interest because it’s vital for proliferation.”

Using bioluminescent markers, scientists can follow the movement of proteins in living cells as they divide.
Using bioluminescent markers, scientists can follow the movement of proteins in living cells as they divide.

What he refers to as “following the red bouncing balls,” has helped Horowitz pinpoint patterns in cell development over the past five years.

“Our big insight is that we’ve forged connections between normal stem cells and their evil twins—uncontrolled stem cells that form tumors.”

Passing on the Glow

From childhood, Horowitz was interested in things he couldn’t see, like DNA and viruses. He feels a responsibility to help inspire and equip the next generation of scientists.

That’s why he took time to talk about what he’s learned from bioluminescent tools in conjunction with the current Glow: Living Lights exhibit at the North Carolina Museum of Natural Sciences.

And it’s why he’s part of the Jimmy V-NC State Cancer Therapeutics Training Program, which has brought 30 young scientists to work in cancer research labs in its first two years.

Though the work isn’t easy, “It’s worthwhile and noble, as well as ridiculously interesting.” And beautiful, too.

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