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From plants to human cells: Universal genetic scissors

It’s a battle for survival. Plants against bacteria. Your habitat, my habitat. And right in the thick of it: Dr. Jens Boch from the Department of Genetics. In 2009 he discovered how certain bacteria are able to genetically manipulate plant cells. Scientists the world over have been able to take advantage of this trick. They have developed innovative genetic scissors which can be used to find out about genetic diseases in human cells.

Cells are the smallest common denominator in bacteria, plants and humans. They contain genetic material. “Their DNA can be used in various ways, for example, by switching genes on and off. Xanthomonas, a pathogenic bacterium, does this to change functions in plant cells,” Boch explains. He unlocked the pathogen’s trick in 2009 together with his former colleague Dr. Sebastian Schornack.

“It is a very straightforward principle: Bacteria have proteins whose building blocks are arranged in a certain order. These proteins, so-called TAL effectors, are locked by the bacteria in the core of the plant cell. There they dock onto the DNA at a given location. If you change the structure of the TAL effectors, you also change the docking point,” the plant geneticist explains. The results vary: “In our case, the bacteria extract sugar from the plant cells and feed off this.”

It’s a discovery that has made researchers around the world sit up and take notice. TAL effectors can do even more. “Connecting them to a certain enzyme results in genetic scissors. It’s actually nothing new, however these genetic scissors only cut at one location, not multiple times in the DNA.” Scientists can more accurately study the effects of a gene that has been manipulated in this way and new information can be more selectedly inserted into the genetic material. Moreover, genetic scissors are less expensive than others. “Now small-scale labs can use them as well. Students can even build them in the lab. That is revolutionary,” says Boch.

A revolution with a lot of potential as genetic scissors can be applied universally and are also used in human cells. “You can detect changes in human genetic material, cut it out and replace it with a new gene. This helps treat genetic diseases though it has so far only worked in individual cells.” In the meantime, more and more scientists are working with TAL effectors. They are improving the functionality and experimenting with additional enzymes.

This year Jens Boch has been awarded a research prize by the Association for General and Applied Microbiology for his pioneering work on the mechanisms of bacterial proteins. “It wasn’t clear to us at the beginning that it would make such an impact, especially in the area of biotechnology.”

And yet green genetic engineering is a process which many people are sceptical about. Boch is aware of his critics argumentation and responds by saying: “Gene manipulation is a natural phenomenon and occurs all the time. Anyone who’s studied the principles of genetics and evolution understands that what you witness today in the natural world is not static. Nature is constantly changing – we’re just speeding up this process and doing it more accurately,” says the researcher. He mainly wants to get the word out on the possibilities of his work. “But I’m also green – just like the scientists that produced the first genetically modified tomato. They just wanted to reduce the amount of pesticides in their food.” Sarah Huke

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