IT鈥橲 now possible to make proteins from genes without using living cells. Roche Molecular Biochemicals of Penzberg, Germany, has developed a kit that does the job in a fraction of the time it takes bacteria. 鈥淵ou need no microbiological expertise to do it, no special laboratory and no cloning experts,鈥� says vice-president Albert R枚der.
Researchers who want to produce proteins for analysis usually stitch the gene into E. coli and get the bacterium to make them. This can be tricky, because E. coli鈥檚 enzymes may break down the desired protein, for example.
So Roche has created a system that contains only the key cellular machinery needed to make proteins. An RNA polymerase isolated from a virus carries out the first step of transcribing DNA into RNA, while an E. coli extract provides the 鈥渇actories鈥� making proteins from the RNA.
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The kit consists of a small tube. RNA and proteins are made in the upper chamber of the cylinder, while the larger 鈥渂ase鈥� chamber supplies nutrients such as amino acids (see Diagram). Unwanted by-products diffuse back into the lower chamber. The reaction takes just 24 hours, as opposed to days in living cells.
鈥淭he trick with this is that it continually exchanges the waste,鈥� says Yen Choo of the Laboratory of Molecular Biology in Cambridge. 鈥淚t will be useful,鈥� he says.