干旱区生态环境知识资源中心

We have focused on the generation of cells of the Schwann cell lineage. The presence of mRNA for the myelin protein Po in migrating neural crest cells suggests that it is an early glial lineage marker. Previously, we identified an intermediate cell type in the Schwann cell lineage, the Schwann cell precursor, which differs in many respects fi-om the immature Schwann cell. Schwann cell precursors are the major cell type in limb nerves at embryo day (E)14/15 (rat) and E12/13 (mouse). During a brief period they convert to immature Schwann cells and the beta-neuregulins are the axonal signals required for survival and maturation to Schwann cells. beta-neuregulins induce sustained high-level phosphorylation of the transcription factor CRE binding protein (CREB) in Schwann cells. Currently, we are identifying genes that regulate the transition from Schwann cell precursors to Schwann cells using differential mRNA fingerprinting methods.

Schwann cells themselves produce autocrine survival signals that regulate their survival in the absence of axons, a property important for nerve regeneration. These signals are absent in precursors and are unlikely to be neuregulins. We have found that Schwann cells express the signalling protein Desert hedgehog (Dhh) which shapes the formation of the perineurial and other connective tissue sheaths around peripheral nerves.