, 2000, Takebayashi et al., 2000 and Zhou et al., 2000). OLIG2 knockout results in loss of the pMN domain and consequently complete absence of spinal MNs Dabrafenib supplier (Lu et al., 2002, Takebayashi et al., 2002,

Zhou and Anderson, 2002 and Park et al., 2002). All spinal OL lineage cells are lost as well because OLIG2 is required for OLP development regardless of whether they are generated within or outside of pMN (Lu et al., 2002, Takebayashi et al., 2002, Zhou and Anderson, 2002 and Park et al., 2002). In contrast, OLIG1 has a relatively mild impact on normal development (Lu et al., 2002; J.P.d.F., N. Kessaris, W.D.R., and H.L., unpublished data; but see Xin et al., 2005). However, OLIG1 is believed to be crucial for OL regeneration in demyelinating diseases such as multiple sclerosis (Arnett et al., 2004). The OLIG gene products are members of a large family of helix-loop-helix (HLH) transcription factors, which also includes proneural proteins Neurogenin1/2 (NGN1/2) and MASH1/ASCL1 as well selleck chemicals as cell

lineage regulators MYOD and NEUROD. OLIG2 interacts with different protein partners to regulate specific developmental processes. It can form heterodimers with NGN2 to control MN differentiation, and it can bind NKX2.2 to promote OLP generation and/or differentiation (Novitch et al., 2001, Zhou et al., 2001, Qi et al., 2001, Sun et al., 2003 and Lee et al., 2005). It can also complex with SOX10 or ZFP488 to regulate OLP differentiation and enhance myelin gene expression (Wang et al., 2006, Wissmuller et al., 2006 and Li et al., 2007). Given the central role of OLIG2 in both MN and OL development, we were keen to discover how this one transcription factor can specify two quite different

PAK6 cell types and especially how it participates in the MN-OLP temporal fate switch. We present evidence that OLIG2 controls the switch by reversible phosphorylation on Serine 147 (S147), a predicted protein kinase A (PKA) target; phosphorylation at this site is required for patterning of the ventral neuroepithelium and MN specification, whereas dephosphorylation favors OLP specification. S147 phosphorylation also causes OLIG2 to switch its preferred dimerization partner from OLIG2 (or OLIG1) to NGN2. We propose that this regulated exchange of cofactors is required for and triggers the MN-OLP fate switch. OLIG2 is rich in serine and threonine residues (50 serines and 14 threonines out of a total of 323 amino acids; see Table S1 available online), suggesting that it might possess multiple serine/threonine phosphorylation sites. To test this, we transfected a Myc epitope-tagged OLIG2 expression vector into Cos-7 cells, labeled the cells with [33P]phosphate, and analyzed radiolabeled OLIG2 proteins by immunoprecipitation (IP) with anti-Myc followed by polyacrylamide gel electrophoresis (PAGE). Two major radioactive OLIG2 bands were visible (Figure 1A).