NEUROBIOLOGY:
Researchers Find Signals That Guide Young Brain Neurons
Marcia Barinaga
To reach their final destinations in the brain, newborn nerve cells have to travel through hoards of other neurons while constantly staying on the alert for the signposts that will direct them to their proper locations. Neurobiologists had few clues to the molecular machinery guiding these migrations until 2 years ago, when they discovered a protein called Reelin, the product of a gene which, when mutated, apparently disrupts the movements of certain brain neurons. Although Reelin looked as if it might be a signal to guide the migrating neurons, at the time no one knew how it might do this. Now, in new work reported in the August issue of Neuron and in this week's Nature, researchers have uncovered a protein that may be part of a signaling pathway triggered by Reelin as it attracts the nerve cells to their destinations. The protein, called mDab1, is made by a gene that is mutated in mice known as scramblers, which have a behavior and brain disorganization that appear identical to those of mice with reelin gene mutations.
