Prion-free cows bred
An American-Japanese research team has bred genetically modified cows that lack the prion protein PrPC. This should protect the animals against BSE mad cow disease.
Misfolded PrPC is considered to be the trigger of various neurodegenerative diseases such as BSE in cattle, scrapie in sheep or Creutzfeldt-Jakob disease in humans. However, the function of the normally folded protein, which is found in numerous organisms primarily in the nervous system, is still unclear. Genetically modified PrPC-free mice develop perfectly normally - but cannot be afflicted with prion diseases.
The researchers led by Jürgen Richt from the State Center for Animal Diseases in Ames have now taken the same path with cattle. The PrPC-free cows appeared normal and he althy at least up to twenty months of age. And in the laboratory, the animals' brain tissue could not be infected with BSE.
The future will have to show whether the genetically modified cows will remain he althy. In mice, there is evidence that normal PrPC plays an important role in the differentiation of neural stem cells into brain cells. (aj)