Yeast may produce healing proteins * Transgenic cells can provide cheaper drugs
Brewer's yeast, enlarged
Yeast engineered to produce human proteins could simply be drug makers. This is according to a study published this weekend in the journal Nature.
Human proteins are widely used as medicines - erythropoietin, for example, strengthens depleted red blood cells after cancer. However, many, called glycoproteins, must be produced in mammalian cells in order for them to contain an essential amount of sugar molecules. This production is expensive and inefficient.
So Tilman Grangros of Dartmouth College in Hanover, New Hampshire and his colleagues tweaked brewer's yeast to add human sugar molecules to the protein. "You just insert a human gene into them and they start producing a human protein." said.
Because yeast grows faster and requires less supervision than mammalian cells, they can make the production of human proteins cheap and easy. Already today, insulin is produced in this way from beer yeast.
One day it will be possible to produce antibodies from human proteins such as herceptin for breast cancer, and many others that are under development using yeast. "This is a huge advance" says Caroline Bertuzzi who studied the glycoproteins at the University of California at Berkeley. "They managed to perform a heroic engineering experiment."
Protein-producing yeasts may also be safer. Yeast produces only one type of glycoprotein while mammalian cells produce a cocktail, explains biochemist Laura Kiesling from the University of Wisconsin in Madison. Each version may stick to the cell or break in a different way, so the mixture is less predictable.
Avi Blizovsky is the editor of the science website http://www.hayadan.org.il
For information in Nature
For information on the Nature website
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