Trees or biofactories?
Even ordinary plants can produce vital proteins like antibodies, hormones and enzymes with a little help from viruses engineered to wear an "overcoat.' Scientists at the Scottish Crop Research Institute (SCRI) in Invergowrie, near Dundee, are producing proteins attached to the virus' own protein coats. Experiments have revealed the products to be biologically active even when they are attached to the viruses. The tests also confirm that virus-infected plants can be used to decontaminate land. The researchers are modifying plant viruses like the tobacco mosaic virus and potato virus X. A virus is usually surrounded by 1,500-2,500 copies of its coat protein. The scientists at SCRI have fused a genetic sequence that encodes the "overcoat' to the virus's own protein coat gene. Within 10 days of the virus infecting a plant, millions of its cells produce up to one million modified virus particles. For some proteins, like drugs that have to be purified before use, the protein should be separated from the virus. But when using antibodies to remove contaminants from water, it is more effective to keep them attached to the viruses as bioactive particles ( New Scientist , Vol 156, No 2113-14).