OLIG2

Oligodendrocyte transcription factor (OLIG2) is a basic helix-loop-helix (bHLH) transcription factor encoded by the OLIG2 gene. The protein is of 329 amino acids in length, 32 kDa in size and contains one basic helix-loop-helix DNA-binding domain. It is one of the three members of the bHLH family. The other two members are OLIG1 and OLIG3. The expression of OLIG2 is mostly restricted in central nervous system, where it acts as both an anti-neurigenic and a neurigenic factor at different stages of development. OLIG2 is well known for determining motor neuron and oligodendrocyte differentiation, as well as its role in sustaining replication in early development. It is mainly involved in diseases such as brain tumor and Down syndrome.

== Function == OLIG2 is mostly expressed in restricted domains of the brain and spinal cord ventricular zone which give rise to oligodendrocytes and specific types of neurons. In the spinal cord, the pMN region sequentially generates motor neurons and oligodendrocytes. During embryogenesis, OLIG2 first directs motor neuron fate by establishing a ventral domain of motor neuron progenitors and promoting neuronal differentiation. OLIG2 then switches to promoting the formation of oligodendrocyte precursors and oligodendrocyte differentiation at later stages of development. Apart from functioning as a neurogenic factor in specification and the differentiation of motor neurons and oligodendrocytes, OLIG2 also functions as an anti-neurogenic factor at early time points in pMN progenitors to sustain the cycling progenitor pool. This side of anti-neurogenicity of OLIG2 later plays a bigger role in malignancies like glioma.