Neuronal PAS Domain Protein 4 (NPAS4)

NXF is a member of the basic helix-loop-helix-PER-ARNT-SIM (bHLH-PAS) class of transcriptional regulators, which are involved in a wide range of physiologic and developmental events.

The deduced 802-amino acid protein contains an N-terminal bHLH domain, followed by 2 PAS domains and a C-terminal activation domain. Northern blot analysis of several adult tissues detected robust expression only in brain, with faint expression in skeletal muscle and kidney. In developing mouse brain, expression of Nxf was only detectable beginning at embryonic day 17 and was higher in the 4-week postnatal brain. In situ hybridization of adult rat brain revealed punctate expression in the cerebral cortex and striatum, with prominent expression in the neuronal cell layers of the hippocampus.