Oligodendrocytes (OLs) are myelin-forming cells that are present within the central nervous system. Impaired oligodendrocyte precursor cell (OPC) differentiation into mature OLs is a major cause of demyelination diseases. Therefore, identifying the underlying molecular mechanisms of OPC differentiation is crucial to understand the processes of myelination and demyelination. It has been acknowle...

A relatively simple preparation of guinea pig brain myelin, free of gross contamination by other cellular elements has been described. Electron microscopic evidence of the predominance of membranous (lamellar) forms was used as the criterion of purity of this fraction. The slight mitochondrial contamination of the myelin fraction was confirmed by its low succinic dehydrogenase activity. Quantit...

The near-neighbor relationships of proteins in the myelin membrane were examined using dinitrodifluorobenzene and other cross-linking reagents. When intact cat dorsal column or isolated myelin fragments were treated with cross-linking reagents, up to 20% of the myelin basic protein dimerized. The only other cross-linked product formed in the intact cat dorsal column was a heterodimer consisting...

Myelin vesicles have been obtained from isolated rat brain myelin and shown by electron microscopy to consist of single bilayer membranes. The yield of the preparation is approximately 25% of the myelin proteins. The vesicles show a typical myelin protein pattern on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and contain activity for the myelin marker enzyme, 2',3'-cyclic nucleoti...

Myelin fractions with different degrees of compaction were isolated from bovine brain, and post-translational methylation of membrane-associated proteins was studied. When the purified myelin-basic-protein-specific protein methylase I and S-adenosyl-L-[methyl-14C]methionine were added exogenously, the most compact myelin fraction exhibited higher methyl-accepting activity than the less compact ...

Myelin, the insulating sheath around axons, supports axon function. An important question is the impact of mild myelin disruption. In the absence of the myelin protein proteolipid protein (PLP1), myelin is generated but with age, axonal function/maintenance is disrupted. Axon disruption occurs in Plp1-null mice as early as 2 months in cortical projection neurons. High-volume cellular quantifica...

Myelin biogenesis is a complex process involving coordinated exocytosis, endocytosis, mRNA transport, and cytoskeletal dynamics. Although abnormalities of myelin are common in lysosomal storage diseases, our understanding of the role of lysosomes in the formation and maintenance of myelin is still limited. Here, we show that late endosomes/lysosomes in Schwann cells contain abundant myelin prot...

The central nervous system (CNS) of terrestrial vertebrates underwent a prominent molecular change when a tetraspan membrane protein, myelin proteolipid protein (PLP), replaced the type I integral membrane protein, P0, as the major protein of myelin. To investigate possible reasons for this molecular switch, we genetically engineered mice to express P0 instead of PLP in CNS myelin. In the absen...

Encephalitogenic basic protein and the enzyme nucleoside 2' :3'-cyclic monophosphate 3'-phosphodiesterase (EC 3.1.4.16) are recognized markers for myelin. Phosphodiesterase activity can be detected in the brains of newborn rats even though myelin cannot be seen by light or electron microscope. The determination of phosphodiesterase activity and the detection of basic protein by Coomassie-Blue s...

The peripheral nerves consist of sensory nerves that transmit somatic and visceral afferent information to the brain via the spinal cord and motor nerves that convey efferent outputs of the brain to effector organs such as skeletal muscles and glands. The nerve conduction velocities (NCV) of mammalian peripheral nerves range from 10 m/s to 150 m/s, depending on the type of information being tra...