RT Journal Article SR Electronic T1 P0 Protein Is Required for and Can Induce Formation of Schmidt-Lantermann Incisures in Myelin Internodes JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 7068 OP 7073 DO 10.1523/JNEUROSCI.0771-08.2008 VO 28 IS 28 A1 Xinghua Yin A1 Grahame J. Kidd A1 Klaus-Amin Nave A1 Bruce D. Trapp YR 2008 UL http://www.jneurosci.org/content/28/28/7068.abstract AB Axons in the PNS and CNS are ensheathed by multiple layers of tightly compacted myelin membranes. A series of cytoplasmic channels connect outer and inner margins of PNS, but not CNS, myelin internodes. Membranes of these Schmidt-Lantermann (S-L) incisures contain the myelin-associated glycoprotein (MAG) but not P0 or proteolipid protein (PLP), the structural proteins of compact PNS (P0) and CNS (PLP) myelin. We show here that incisures are present in MAG-null and absent from P0-null PNS internodes. To test the possibility that P0 regulates incisure formation, we replaced PLP with P0 in CNS myelin. S-L incisures formed in P0-CNS myelin internodes. Furthermore, axoplasm ensheathed by 65% of the CNS incisures examined by electron microscopy had focal accumulations of organelles, indicating that these CNS incisures disrupt axonal transport. These data support the hypotheses that P0 protein is required for and can induce S-L incisures and that P0-induced CNS incisures can be detrimental to axonal function.