Myelin is a biologically active membrane receiving and processing signals from axons. Although much is known about its structure and molecular composition, the intracellular signal transduction pathways, active during specific phases of myelinogenesis for regulating myelin formation, remain poorly understood. Recent genetic loss-of-function studies have suggested a key role of extracelluar sign...

Dedifferentiation of myelinating Schwann cells is a key feature of nerve injury and demyelinating neuropathies. We review recent evidence that this dedifferentiation depends on activation of specific intracellular signaling molecules that drive the dedifferentiation program. In particular, we discuss the idea that Schwann cells contain negative transcriptional regulators of myelination that fun...

PURPOSE To analyze the cortical gyral patterns and myelination patterns in a series of patients with congenital cytomegalovirus infections involving the central nervous system, to correlate them with known developmental events, and to develop a consistent theory regarding their embryogenesis. METHODS The MR (11 patients) and CT (four patients) studies of 11 patients with congenital cytomegalo...

The specific axonal and Schwann cell surface molecules that mediate the initiation of myelination have not been identified. We have used cocultures of purified rat dorsal root ganglion neurons and Schwann cells and purified polyclonal antibodies to the L1 adhesion molecule to study the role of L1 in myelin formation. Schwann cells were first arrested in a basal-lamina-free premyelination stage ...

For differentiation, Schwann cells rely on the class III POU domain transcription factor Oct-6, which is expressed transiently when Schwann cells have established a one-to-one relation with axons but have not yet started to myelinate. Loss of Oct-6 leads to a transient arrest in this promyelinating stage and a delay in myelination. Although the closely related POU domain protein Brn-2 is coexpr...

The PI 3-kinase (PI 3-K) signaling pathway is essential for Schwann cell myelination. Here we have characterized PI 3-K effectors activated during myelination by probing myelinating cultures and developing nerves with an antibody that recognizes phosphorylated substrates for this pathway. We identified a discrete number of phospho-proteins including the S6 ribosomal protein (S6rp), which is dow...

We present a mini review of the microscopical techniques that may be used to investigate the process of myelination in the tissues of the mammalian central nervous system. The biological background to myelination, the process by which neuronal axons are electrically insulated to achieve higher conduction velocities is outlined, including an introduction to neurons and glia, some background disc...

Myelination, the elaboration of myelin surrounding neuronal axons, is essential for normal brain function. The development of the myelin sheath enables rapid synchronized communication across the neural systems responsible for higher order cognitive functioning. Despite this critical role, quantitative visualization of myelination in vivo is not possible with current neuroimaging techniques inc...

Recent findings suggest the formation of myelin in the central nervous system by oligodendrocytes is a continuous process that can be modified with experience. For example, a recent study showed that immobilization stress increased oligodendrogensis in the dentate gyrus of adult rat hippocampus. Because changes in myelination represents an adaptive form of brain plasticity that has a greater re...

Salla disease and infantile sialic acid storage disease are autosomal recessive lysosomal storage disorders caused by mutations in the gene encoding sialin, a membrane protein that transports free sialic acid out of the lysosome after it is cleaved from sialoglycoconjugates undergoing degradation. Accumulation of sialic acid in lysosomes defines these disorders, and the clinical phenotype is ch...