Where am I?
MICE that have been genetically altered to make a human protein linked to Alzheimer’s disease get lost easily. Neurologist Lennart Mucke and colleagues at the University of California, San Francisco, replaced the mouse gene for ApoE, a protein that transports lipids in the brain, with one of two variants of the human version, E3 or E4 ( Proceedings of the National Academy of Sciences, vol 95, p 10914). E4 is associated with a higher risk of Alzheimer’s disease, but scientists do not know why. As they aged, the mice with E4 began to have problems recalling the location of a platform hidden in milky water. But the mice did not develop the tangles and plaques in their brains that are the hallmark of Alzheimer’s. “We don’t want to recreate the disease in every detail,