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Published on: November 10, 2015
Tryptophan hydroxylase-2 controls brain serotonin synthesis
Xiaodong Zhang1, Jean-Martin Beaulieu, Tatyana D Sotnikova
1Howard Hughes Medical Institute Laboratory, Department of Cell Biology, and Center for Models of Human Disease, Institute for Genome Sciences and Policy, Box 3287, Duke University Medical Center, Durham, NC 27710, USA.
Science (New York, N.Y.)
|July 13, 2004
Summary
A genetic variation in Tryptophan hydroxylase-2 (Tph2) reduces brain serotonin levels. This finding highlights Tph2's critical role in regulating serotonin synthesis, impacting psychiatric disorder research.
Area of Science:
- Neuroscience
- Genetics
- Biochemistry
Background:
- Serotonin (5-HT) is a key neurotransmitter implicated in numerous psychiatric disorders.
- Tryptophan hydroxylase-2 (Tph2) is the primary enzyme responsible for serotonin synthesis in the brain, distinct from Tph1 found peripherally.
- Understanding Tph2's function is crucial for developing treatments for mood and behavioral disorders.
Purpose of the Study:
- To investigate the functional impact of a specific single-nucleotide polymorphism (SNP) in the mouse Tph2 gene.
- To determine the effect of this Tph2 genetic variation on brain serotonin levels and synthesis rates.
- To establish the direct role of Tph2 in regulating central serotonergic neurotransmission.
Main Methods:
- Genotyping of mouse strains (BALB/cJ, DBA/2, C57Bl/6, 129X1/SvJ) to identify the presence of the C1473G Tph2 SNP.
- In vitro assessment of Tph2 enzyme activity using PC12 cells expressing the variant.
- Quantification of brain serotonin tissue content and synthesis rates in mice with different Tph2 genotypes.
Main Results:
- A functional C1473G SNP in mouse Tph2 was identified, leading to a Pro447Arg amino acid substitution.
- This Tph2 variant resulted in significantly decreased serotonin levels in PC12 cells.
- Mice homozygous for the 1473G allele (BALB/cJ, DBA/2) exhibited reduced brain serotonin content and synthesis compared to mice with the 1473C allele (C57Bl/6, 129X1/SvJ).
Conclusions:
- The study provides direct evidence that Tph2 is fundamentally involved in brain serotonin synthesis.
- The identified C1473G SNP in Tph2 acts as a functional variant impacting central serotonin levels.
- These findings have implications for understanding the genetic basis of psychiatric disorders linked to serotonin dysregulation.
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