NPAS3 or Neuronal PAS domain protein 3 is a brain-enriched

transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...

belonging to the bHLH-PAS superfamily of transcription factors, the members of which carry out diverse functions, including

circadian oscillations A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to ...

neurogenesis Neurogenesis is the process by which nervous system cells, the neurons, are produced by neural stem cells (NSCs). It occurs in all species of animals except the porifera (sponges) and placozoans. Types of NSCs include neuroepithelial cells (NECs ...

toxin A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849 ...

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...

, hypoxia, and

trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from th ...

l development. NPAS3 contains

basic helix-loop-helix BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

structural motif and

PAS domain A Per-Arnt-Sim (PAS) domain is a protein domain found in all kingdoms of life. Generally, the PAS domain acts as a molecular sensor, whereby small molecules and other proteins associate via binding of the PAS domain. Due to this sensing capability ...

, like the other proteins in the superfamily.

Function

NPAS3 is also known as human accelerated region 21. It may, therefore, have played a key role in differentiating humans from apes. NPAS1 and NPAS3-deficient mice display behavioral abnormalities typical to the animal models of

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wi ...

. According to the same study, NPAS1 and NPAS3 disruption leads to reduced expression of

reelin Reelin, encoded by the ''RELN'' gene, is a large secreted extracellular matrix glycoprotein that helps regulate processes of neuronal migration and positioning in the developing brain by controlling cell–cell interactions. Besides this impor ...

, which is also consistently found to be reduced in the brains of human patients with

and psychotic

bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...

. Among the 49 genomic regions that undergone rapid changes in humans compared with their evolutionary ancestors, NPAS3 was found to be located in the region 21.

Clinical significance

Disruption of NPAS3 was found in one family affected by schizophrenia and NPAS3 gene is thought to be associated with psychiatric illness and learning disability. In a genetic study of several hundred subjects conducted in 2008, interacting

haplotype A haplotype ( haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA or ...

s at the NPAS3 locus were found to affect the risk of schizophrenia and

. In a pharmacogenetical study, polymorphisms in NPAS3 gene were highly associated with response to iloperidone, a proposed atypical antipsychotic.Lavedan C, Volpi S, Mack K, et al. Whole-genome association study identifies polymorphisms in the NPAS3 gene associated with super-response to iloperidone treatment in patients with schizophrenia. Program and abstracts of the 57th Annual Meeting of the American Society of Human Genetics; October 23–27, 2007; San Diego, California. Abstract 1035/T

Function

Clinical significance

References

Further reading