Gene removal could have implications beyond plant science

Apr 16, 2014 by Rosaire Bushey

(Phys.org) —For thousands of years humans have been tinkering with plant genetics, even when they didn't realize that is what they were doing, in an effort to make stronger, healthier crops that endured climates better, and produced more.

Zachary Nimchuk, assistant professor of biological sciences and a member of the faculty of health sciences at Virginia Tech, is working with a technology that refines the process by honing in on individual genes within a plant's DNA.

Nimchuk builds on a technology developed by George Church, a professor of genetics at the Harvard Medical School that knocks out specific genes in a plant's DNA to get rid of a trait that is unwanted, or add a trait that is desirable. This process was discovered by looking at bacteria and how they take the DNA of invading viruses and use it to immunize themselves against further attacks.

"We realized the system could be used as a way to edit and modify genomes from higher organisms," Nimchuk said. "Unlike traditional crossing of plants which may allow for the transmission of both desired and undesired traits, we are taking out the specific traits we don't want, or adding what we do want, without removing or adding additional unwanted traits. And we're doing it without introducing any foreign DNA into the plant meaning it's not a genetically modified organism as people understand GMO, in the traditional sense."

The technology is a system made up of two components, an enzyme and RNA. The enzyme, CAS9, has the ability to chop up DNA and, as Church's group originally showed, RNA can guide and bind the enzyme to a target gene. The chewing activity within the enzyme will chop the DNA in half which allows scientists to install repair genes. The process has the effect of allowing the removal of a very specific unwanted trait and replacing it with a very specific desired trait allowing researchers to determine the role of the removed gene.

For Virginia Tech scientists, the implications of Nimchuk's research is far-reaching because the technology can be used in any system and target any gene. For instance, the potential is large as it relates to being able to target and replace specific genes that might contribute to disease states in humans by replacing a mutated gene with a normally functioning gene as a therapy.

For Nimchuk, however, his work is focused on plants and crops and how they are used to fuel society or feed people. "We are looking at genes that might help control salt tolerance, crop yields, or other environmental factors to include how crops fend off pathogens," he said. "We're at a tip of the iceberg stage of seeing what we can and cannot do, but it's an exciting time to be using the technology right now."

Nimchuk, a native of Toronto who received his doctorate from the University of North Carolina, Chapel Hill, and who is fresh off post-doctoral work at Cal Tech, joined Virginia Tech in the fall of 2013 and is already collaborating with scientists in working in other fields.

"Every organism has DNA, and RNA is capable of binding with other DNA molecules, so essentially that basic machinery is going to be compatible with every system," Nimchuk said. "This has been shown to work in everything from fish to frogs to flies to human cells and yeast, so we know the technology works. I'm hoping this will be a technology that can be taken up by anybody who works with a biological system and who has an interesting question or problem they want solved."

Explore further: Researchers reverse a liver disorder in mice by correcting a mutated gene

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