Phosphorylation Regulates OLIG2 Cofactor Choice and the Motor Neuron-Oligodendrocyte Fate Switch

Huiliang Li,Joana Paes De Faria,Paul Andrew,Justyna Nitarska,William D Richardson

doi:10.1016/j.neuron.2011.01.030

Huiliang Li, Joana Paes De Faria + Show 3 more

Open Access

https://doi.org/10.1016/j.neuron.2011.01.030

Copy DOI

Abstract

SummaryA fundamental feature of central nervous system development is that neurons are generated before glia. In the embryonic spinal cord, for example, a group of neuroepithelial stem cells (NSCs) generates motor neurons (MNs), before switching abruptly to oligodendrocyte precursors (OLPs). We asked how transcription factor OLIG2 participates in this MN-OLP fate switch. We found that Serine 147 in the helix-loop-helix domain of OLIG2 was phosphorylated during MN production and dephosphorylated at the onset of OLP genesis. Mutating Serine 147 to Alanine (S147A) abolished MN production without preventing OLP production in transgenic mice, chicks, or cultured P19 cells. We conclude that S147 phosphorylation, possibly by protein kinase A, is required for MN but not OLP genesis and propose that dephosphorylation triggers the MN-OLP switch. Wild-type OLIG2 forms stable homodimers, whereas mutant (unphosphorylated) OLIG2S147A prefers to form heterodimers with Neurogenin 2 or other bHLH partners, suggesting a molecular basis for the switch.

Highlights

All the neurons and glial cells of the mature central nervous system (CNS) are generated by neuroepithelial stem cells (NSCs) in the ventricular zone (VZ) that surrounds the lumen of the embryonic neural tube
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 motor neurons (MNs) specification, whereas dephosphorylation favors oligodendrocyte precursors (OLPs) specification
Cotransfection of Olig2WT with a plasmid encoding a dominant-negative form of PKA strongly reduced the phosphoprotein signal in the low pH range of the 2D gel, implying that OLIG2 can be phosphorylated by PKA on several sites, including S147 (Figure 1E)

Summary

SUMMARY

A fundamental feature of central nervous system development is that neurons are generated before glia. In the embryonic spinal cord, for example, a group of neuroepithelial stem cells (NSCs) generates motor neurons (MNs), before switching abruptly to oligodendrocyte precursors (OLPs). We asked how transcription factor OLIG2 participates in this MNOLP fate switch. We found that Serine 147 in the helix-loop-helix domain of OLIG2 was phosphorylated during MN production and dephosphorylated at the onset of OLP genesis. Mutating Serine 147 to Alanine (S147A) abolished MN production without preventing OLP production in transgenic mice, chicks, or cultured P19 cells. We conclude that S147 phosphorylation, possibly by protein kinase A, is required for MN but not OLP genesis and propose that dephosphorylation triggers the MN-OLP switch. Wild-type OLIG2 forms stable homodimers, whereas mutant (unphosphorylated) OLIG2S147A prefers to form heterodimers with Neurogenin 2 or other bHLH partners, suggesting a molecular basis for the switch

INTRODUCTION

RESULTS

EXPERIMENTAL PROCEDURES