AN2
1
is the mouse homolog of the rat NG2 and human MCSP protein. NG2 is a chondroitin sulfate glycoprotein that is expressed by glial progenitor cells in the developing and adult central nervous system (CNS) and by immature Schwann cells.
NG2/AN2
+
glia has been identified as a fourth major glial cell type in the mammalian CNS that is distinct from other cell types
2
. NG2/AN2
+
cells are precursors of oligodendrocytes and some protoplasmic astrocytes in the grey matter
3
. NG2/AN2 expression is down-regulated before the cells undergo terminal differentiation. However, a population of NG2/AN2
+
cells remain in the white and grey matter after oligodendrocytes are generated
4-6
.
NG2/AN2
+
glial cells participate in neuron-glial circuits by receiving presynaptic input from neurons and responding to neurotransmitters released by synapses
7
.
Many highly migratory neural tumors including melanomas express NG2/AN2.