Differentiation stages of Schwann cells and commonly expressed molecules. Unlike oligodendrocytes, immature Schwann cells may differentiate into two distinct phenotypes, myelinating (left) and non-myelinating (right) Schwann cells. However, differentiation is reversible as indicated by the dotted arrows. Blue boxes represent markers of myelinating Schwann cells and molecules promoting their differentiation. All of these markers display strong up-regulation in the stage of myelination. Red boxes include markers of non-myelinating and immature Schwann cells, which are down-regulated during myelination. Note that p75NTR is expressed in all differentiation stages except in myelinating Schwann cells. Whether the detected p75NTR expressing bipolar cells in CDV-DL differentiate into myelinating Schwann cells is currently not known. Markers and scheme modified from Mirsky et al., 2008 [141].