Researchers make chromosomes to order

Breakthrough may ease development of foods, medicines

Source: Chicago Tribune
Date: October 19, 2007

By Jon Van Tribune staff reporter


It's been a brave new world for genetic crops for some time now but Chicago-based researchers say they have developed a method to take crop manipulation to a higher level: the chromosome.


Creating an artificial chromosome, into which several manipulated genes can be inserted, may speed efforts to produce fuels and medicines from plants as well as boosting crop nutrition and yield.


In a scientific paper set for publication Friday researchers from Chicago-based Chromatin Inc. and the Universities of Chicago and North Carolina reported success in creating an artificial chromosome for corn plants. Through four generations, the corn treated the man-made chromosomes as if they were natural and passed them along to offspring intact at a rate nearly as high as for chromosomes native to the plants.


"This appears to be the tool that agricultural scientists and farmers have long dreamed of," said Daphne Preuss, a University of Chicago professor of molecular genetics and Chromatin's president.


Preuss said that adding a chromosome to a plant's genetic makeup is more useful to scientists than adding individual genes one at a time, as is the way most genetic engineering is done now.


When a single gene is added to a plant its placement tends to be random, so many plants must be used to get a few that use the new gene to acquire a trait, such as better tolerance for drought. Often, a plant needs two or three new genes to acquire drought resistance, Preuss said, which is difficult to achieve using today's technology.


An artificial chromosome can carry several desired genes and be inserted in a targeted location in a plant, she said, giving scientists the power to imbue plants with desired traits much more quickly and reliably than has been possible before.


Earlier this year Monsanto Co. signed a non-exclusive agreement to use Chromatin's technology and Chromatin has been in discussions with several other agribusiness firms, expecting to conclude similar agreements.


The corn results "will make Monsanto very pleased, I'm sure," said Michael Hogg, a Chicago attorney who specializes in biotech matters.


"This is a very big deal," said Ron Meeusen, a biotech veteran who heads an Indianapolis biotech venture capital fund."


We have a ceiling in what we can do with crops. If you want to insert one, two or three genes, that is doable. But if you need more genes than that to make the next improvement, it starts to get much tougher," said Meeusen, who does not have a financial interest in Chromatin.


"Many traits in crops might need seven, 12 or 15 genes, and we cannot do that today. Putting them in individually is like trying to put Humpty Dumpty together again. Chromatin has opened the ceiling on what we can do.


"They've demonstrated this isn't just a lab curiosity. It can actually be used," he said.


Technique started with weeds


Preuss developed the artificial chromosome technique when doing academic studies of weeds but much development work was needed to adapt the technology to corn. Chromatin researchers are working to adapt their techniques to other plants, including switch grass and sugar cane, seeking to help researchers make those crops more productive when they are converted to ethanol fuels.


Chromatin's techniques may also be adapted for creating plants that yield therapeutic products. Making drugs from plants is a young field, but some commercial biotech operations have products in development.


A Canadian firm, SemBioSys Genetics Inc., seeks to use safflower plants to produce insulin, and Biolex Inc. in North Carolina is working to produce monoclonal antibodies from aquatic plants.


Many varieties of soybeans, corn and other cash crops have resulted from genetic manipulation that has been under way for a generation.


Food crops in particular have stirred some opposition from people who believe that such manipulation is dangerous. European activists opposed to "Frankenfoods" have successfully retarded embrace of genetically modified crops in much of the world.


Chromatin's technology is intended to give scientists tools to make their work more targeted and efficient, said Preuss, who is on leave from her university post to oversee the technology's commercialization.


Safety called vital


"It is subject to the same regulation as any genetic manipulation," she said. "No matter how you put a gene into a plant, it is all regulated. Government agencies look at varieties produced by our partners and investigate the safety. This isn't a way to avoid that. We insist that the plants are properly examined.


"Successful implantation of the artificial chromosomes, which researchers call "mini-chromosomes," will be published in the journal PLoS-Genetics.

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