Gli2 Is Not Required in Late Olig2-expressing Motor Neuron Progenitors in the Spinal Cord

The purpose of this study was to determine the function of the transcription factor Gli2 in a subset of Olig2-expressing motor neuron progenitors in the spinal cord of embryonic day 10.5 (E10.5) mouse; approximately two days after the onset of motor neuron specification. To achieve this goal, we extracted control and Gli2 mutant E10.5 embryos; then sectioned the spinal cord at the forelimb (FL) level, followed by a detailed protocol for immunohistochemistry for the transcription factors Pax6, Nkx2.2, and Hb9. These transcription factors define ventral spinal cord progenitor domains and postmitotic motor neurons. We then imaged the transverse spinal cord sections using a Zeiss 710 Confocal laser imaging microscope (z-stack at 20X). All images and data were analyzed with the same parameters. The cells were then quantified for co-expression of GFP and Pax6, Nkx2.2, or Hb9 in Adobe Photoshop. Data were analyzed using the student t-test in Excel spreadsheet. Results of the student t-test showed no significant differences between control and Gli2 conditional mutant spinal cords. We discuss the significance and factors that may contribute to these findings.