PMP22, P0, and MBP protein levels are reduced significantly in TrJ nerves, whereas MAG remains normal. Total sciatic nerve homogenates of 18-d-old (P 18) wild-type (+/+), heterozygous (−/+), homozygous (−/−), and adult wild-type (+/+) and heterozygous (−/+) mice were analyzed for the expression of four different myelin proteins, MAG, P0, PMP22, and MBP. All lanes contain 25 μg of total protein. Molecular weights are indicated in kilodaltons.