Transcription factor required for the development of GABAergic interneurons in the dorsal horn of the spinal cord and migration and further development of hypaxial muscle precursor cells for limb muscles, diaphragm and hypoglossal cord. Interacts with SKOR1 which acts as a transcriptional corepressor. Expressed in the dorsal part of the spinal cord and hindbrain and in presumptive myogenic cells in lateral regions of differentiating somites. Expressed in the developing central nervous system from 10.5 dpc to 16.5 dpc. Expressed in presumptive myogenic cells from 9.5 dpc until 16.5 dpc with highest levels at 10.5-11.5 dpc. Death at birth. Mice fail to expand their lungs and do not move their abnormally thin limbs.