Recombinant Mouse Trace amine-associated receptor 2 (Taar2)
Description
Definition and Biological Context
TAAR2 is a member of the trace amine-associated receptor family, primarily expressed in olfactory epithelium, limbic brain regions (e.g., hippocampus, hypothalamus), and leukocytes . It regulates dopamine levels, neurogenesis, and electrophysiological activity in the brain . Recombinant TAAR2 refers to a synthetic, laboratory-produced version of this receptor, engineered for functional studies in vitro.
Applications in Research
Recombinant TAAR2 is utilized to study:
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Ligand Binding: Testing interactions with trace amines (e.g., β-phenylethylamine, tyramine) and synthetic compounds .
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Signaling Pathways: Investigating G-protein coupling and downstream cAMP or calcium signaling .
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Disease Modeling: Exploring links to schizophrenia and bipolar disorder, where TAAR2 mutations are implicated .
Table 1: Potential Applications of Recombinant TAAR2
| Application | Description | Relevance |
|---|---|---|
| Ligand Screening | High-throughput assays to identify agonists/antagonists. | Drug discovery for neuropsychiatric disorders. |
| Structural Studies | Cryo-EM or X-ray crystallography to resolve receptor conformation. | Understanding ligand-receptor interactions. |
| Functional Assays | Measuring cAMP production or calcium mobilization in response to ligands. | Validating receptor activity. |
Challenges and Considerations
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Signal Transduction: TAAR2’s exact G-protein coupling mechanism remains unclear, requiring functional assays with recombinant proteins .
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Species Specificity: Mouse TAAR2 may differ structurally from human TAAR2, necessitating cross-species validation .
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Stability: Repeated freezing/thawing degrades the protein, requiring careful handling .
Product Specs
Note: We prioritize shipping the format we have in stock. However, if you have a specific format requirement, please indicate it during order placement. We will accommodate your request.
Note: All our proteins are shipped with standard blue ice packs. If dry ice shipping is required, please communicate this in advance, as additional fees will apply.
Generally, the shelf life of liquid form is 6 months at -20°C/-80°C. The shelf life of lyophilized form is 12 months at -20°C/-80°C.
Target Background
Q&A
Basic Research Questions
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What is the expression pattern of mouse TAAR2 in the brain?
TAAR2 is expressed beyond the olfactory system, with significant expression in limbic brain areas. Using β-galactosidase (LacZ) staining in TAAR2-KO mice with LacZ reporter insertion, researchers have identified TAAR2 expression in multiple brain regions including:
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Glomerular and inner layers of the olfactory bulb
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Piriform cortex
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Hippocampus (particularly CA1 layer)
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Hypothalamus
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Lateral habenula
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Raphe nuclei
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Somatosensory cortex (layer 5)
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Cerebellum
LacZ staining showed that TAAR2 is not limited to olfactory neurons but is present in limbic brain areas that receive olfactory input, suggesting broader neurological functions .
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How is TAAR2 knockout verified in mouse models?
TAAR2 knockout (TAAR2-KO) verification typically involves multiple complementary techniques:
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Genetic verification: PCR-based genotyping using primers specific to both wild-type and knockout alleles. The knockout gene typically shows a 400 bp band, while the wild-type gene shows a 200 bp band .
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mRNA confirmation: RT-PCR to detect the presence of TAAR2 mRNA in tissues such as olfactory epithelium and olfactory bulb. While mRNA is detected in wild-type mice, it should be absent in TAAR2-KO mice .
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Reporter gene expression: When using LacZ reporter gene insertion, β-galactosidase activity confirms the site of TAAR2 promoter activity. This allows visualization of where TAAR2 would normally be expressed .
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qPCR quantification: Real-time PCR to measure expression levels across brain regions, comparing wild-type mice with TAAR2-KO mice to verify complete absence of TAAR2 expression .
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What behavioral phenotypes are observed in TAAR2 knockout mice?
TAAR2-KO mice display several distinct behavioral phenotypes compared to wild-type mice:
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Increased locomotor activity: Significantly higher horizontal activity during 120-minute assessments [F(1,34) = 5.843, p = 0.021] .
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Normal exploratory behavior: No difference in initial 5-minute exploration or distance traveled in open field tests .
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Unchanged anxiety levels: Similar performance in elevated plus-maze tests with no difference in time spent in open arms .
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Antidepressant-like behavior: Less immobility time in the forced swimming test, suggesting resistance to behavioral despair .
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Normal pain perception: No significant differences in hot plate test reactions .
These findings suggest TAAR2 may play roles in locomotor regulation and mood-related behaviors without affecting anxiety or exploratory behaviors.
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How does TAAR2 differ structurally from other TAARs?
The TAAR family shares structural similarities as G protein-coupled receptors, but TAAR2 has specific features:
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TAAR2 contains a large number of extracellular leucine-rich repeats (LRRs) .
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Like other TAARs, TAAR2 has seven transmembrane domains with specific binding residues that determine ligand specificity.
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Key binding residues in TAAR proteins generally include conserved aspartate residues (D3.32) in transmembrane domain 3, which are crucial for amine binding .
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Species differences in TAAR2 sequence, particularly in transmembrane domains 6 and 7, may contribute to differences in ligand recognition and binding properties .
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Unlike TAAR1, which has well-established endogenous ligands, the specific natural ligands for TAAR2 are less well-characterized, though its structure predicts high affinity for primary amines .
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