Transcriptional regulator that is critical for the regulation of pain perception and processing of noxious stimuli. Expressed in brain (at protein level) (PubMed:23300874). Expressed at the highest levels in the pyramidal cell layer of the hippocampus, the suprachiasmatic nucleus, laterodorsal thalamic nucleus, lateral geniculate nucleus, substantia nigra pars compacta, and magnocellular part of the red nucleus (at protein level) (PubMed:23300874). Highly expressed in dorsal root ganglia (PubMed:29253101). Expressed at lower levels in kidney, stomach, liver, heart and testis (PubMed:16257534, PubMed:23300874). Detected at 11.5 days post coitum (dpc) in developing brain, and continues to be expressed all the way through to postnatal day 21 (PubMed:23300874). In brain, expressed at 13.5 dpc in thalamus, hypothalamus, midbrain and pontine area (PubMed:16257534). Expression in specific regions of the developing brain is negatively regulated by its antisense mRNA. In particular, down-regulated in pyramidal and granule cells in the hippocampus during early differentiation and the migration stage. Knockout mice exhibit a range of subtle behavioral abnormalities. Locomotor activity is generally increased, but only in familiar environments. There is a slight increase in depression-like behavior, most notably increased immobility in the tail suspension test. Assays of anxiety-like behavior give conflicting results; the open field test indicates a slight reduction in anxiety-like behavior whereas other tests show no significant behavioral changes (PubMed:23300874). Knockout mice are hyposensitive to noxious mechanical stimuli applied to the tail and hypersensitive to noxious heat (PubMed:29253101). Extended N-terminus.