A new mechanism that could underlie certain neurodegenerative diseases is published online this week by Nature. The researchers reveal that upsetting the accuracy of translation, the process by which messenger RNAs are coded into proteins, can lead to the accumulation of misfolded proteins.
Susan Ackerman and colleagues studied mice with the so-called 'sticky' mutation, which develop tremors, movement problems and cellular death of cerebellar neurons. The results of the study implicate the faulty manufacture of transfer RNAs (tRNAs) - the molecules that insert amino acids into their appropriate position during translation - as the reason behind the neurodegeneration seen in sticky mice. The team showed that the sticky mutation disrupts an enzyme called alanyl-tRNA synthetase, which attaches a specific amino acid to tRNA molecules. The mutation causes the production of proteins containing aberrant amino acids, and these proteins cannot
fold correctly and so accumulate within neurons, killing them. The researchers propose that some heritable diseases could be caused by mild mutations that disrupt tRNA synthetase enzymes.
Susan L Ackerman (Howard Hughes Medical Institute, Jackson Laboratory, Bar Harbor, ME, USA)
(C) Nature press release.
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