By generating transgenic mice which selectively express a mutant Ras gene in their neurons, Heumann et al. (page 1537) have found that the Ras signaling pathway can trigger neuroprotective mechanisms in adult mice. The findings suggest a novel approach for stabilizing isolated neurons, and may lead to the development of a new class of therapies for neurodegenerative diseases.
Earlier studies suggested that Ras may mediate some neuronal survival signals, but experiments with different types of neurons have given conflicting results. To address the issue in vivo, the authors of the new study created transgenic mice in which the neuronal promoter for the synapsin-1 gene drives expression of constitutively activated Ha-Ras. Neuronal Ras in these mice is constitutively active, leading to phosphorylation of mitogen-activated kinase. Choline acetyltransferase and tyrosine hydroxylase activities, as well as neuropeptide Y expression, are also increased...
