WE KNOW that rogue prions cause CJD and mad cow disease, but what normally folded prion proteins do has been a mystery, because experimental mice without them are almost normal.
Now Edward M谩laga-Trillo and colleagues at the in Germany have discovered that depriving zebrafish of prions has a much more obvious effect. This holds out hope for future drug development (PLoS Biology, ).
鈥淏locking one form of the normal prion stops the zebrafish brain developing correctly鈥�
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Zebrafish have two versions of the protein. Blocking one stops the brain forming correctly; blocking the other stops the cell migration that guides embryo growth. Time-lapse photos show that the prions help cells to signal and stick to each other.
The finding may explain why disrupting normal prion production causes the dementia of CJD. 鈥淚n fish embryos we see the protein helping cells communicate,鈥� M谩laga-Trillo told New Scientist. 鈥淚t may do something analogous in the mammalian brain, such as building synapses. That may be what goes wrong in prion diseases.鈥�
The work also means zebrafish might be useful in drug development. Because disrupting prions has such dramatic effects in these embryos, a drug that protects the protein should be easy to identify.