UGT84B1 Antibody
Description
Biological Role of UGT84B1
UGT84B1 is a glucosyltransferase that regulates the homeostasis of two major auxins:
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Indole-3-acetic acid (IAA): The primary auxin driving organogenesis and growth .
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Phenylacetic acid (PAA): A secondary auxin abundant in plants, with distinct transport and signaling properties .
UGT84B1 catalyzes the glucosylation of both IAA and PAA into inactive conjugates (IAA-Glc and PAA-Glc), modulating their bioactive levels . Knockout mutants (ugt84b1-c1, ugt84b1-c2) exhibit 1.2–1.4-fold increases in free IAA and PAA levels, while overexpression lines (UGT84B1ox) show auxin-deficient root phenotypes despite elevated IAA/PAA due to compensatory hydrolysis .
Applications of the UGT84B1 Antibody
The antibody is primarily used to:
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Validate protein expression in genetic mutants (e.g., CRISPR/Cas9 knockouts) .
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Quantify UGT84B1 levels in overexpression lines (e.g., pMDC7:UGT84B1) .
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Study tissue-specific localization, given UGT84B1’s preferential expression in reproductive tissues like siliques .
Table 1: UGT84B1 Functional Insights
Table 2: Biochemical Properties of UGT84B1
| Substrate | Catalytic Efficiency (k<sub>cat</sub>/K<sub>m</sub>) | Product |
|---|---|---|
| IAA | 0.74 ± 0.09 mM⁻¹s⁻¹ | IAA-Glc |
| PAA | 4.74 ± 0.48 mM⁻¹s⁻¹ | PAA-Glc |
Experimental Validation
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CRISPR/Cas9 Mutants: The antibody confirmed the absence of UGT84B1 in ugt84b1-c1 and -c2, which harbor 1,159–1,160 bp deletions .
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Overexpression Lines: Immunoblotting revealed 5.5-fold higher UGT84B1 levels in UGT84B1ox roots .
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Tissue-Specific Profiling: qRT-PCR and antibody-based assays showed 30-fold higher UGT84B1 expression in siliques versus seedlings .
Technical Considerations
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Cross-Reactivity: UGT84B1 shares homology with other auxin UGTs (e.g., UGT74D1, UGT74E2), necessitating specificity validation .
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Limitations: PAA-Glc remains unquantified in planta due to technical challenges in LC-MS/MS detection .
Implications for Auxin Research
UGT84B1’s dual substrate specificity highlights its role in fine-tuning auxin signaling. The antibody enables mechanistic studies of glucosylation-dependent auxin homeostasis, particularly in stress responses or developmental transitions .
Product Specs
Target Background
Q&A
Here’s a structured FAQ for researchers studying UGT84B1 antibodies, organized by scientific depth and methodology, with integrated data and citations:
Table 1: Auxin metabolite levels in WT vs. UGT84B1 mutants
Advanced Research Questions
How to resolve contradictions in UGT84B1 substrate specificity reports?
Discrepancies arise from:
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In vitro vs. in vivo conditions: UGT84B1 shows broader substrate promiscuity (e.g., IBA, cinnamic acid) in vitro , but in vivo activity is constrained by tissue-specific cofactor availability .
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Methodological calibration: Compare catalytic efficiency (kcat/Km) across substrates under standardized UDP-glucose concentrations .
What genetic or biochemical interactions complicate UGT84B1 antibody-based studies?
Potential confounders include:
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Hydrolase activity: Overexpression of UGT84B1 paradoxically increases free IAA levels, suggesting endogenous IAA-Glc hydrolases actively recycle conjugated auxins .
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Epistatic interactions: Double mutants with other UGTs (e.g., UGT74E2) may mask phenotypes due to functional redundancy .
Can UGT84B1 antibody studies inform translational work in non-plant systems?
Yes, via:
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Structural homology modeling: UGT84B1’s substrate-binding pocket shares motifs with human UGT2B7, a drug-metabolizing enzyme .
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Cross-species activity screens: Test antibody cross-reactivity with bacterial/mammalian UGTs using phage display libraries .
Methodological Recommendations
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For enzyme kinetics: Use Lineweaver-Burk plots to distinguish competitive vs. non-competitive inhibition (e.g., carprofen enantiomers’ effects on UGT2B7) .
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For antibody development: Prioritize single-domain antibodies (sdAbs) for epitope-specific recognition, as demonstrated for Mycobacterium Ag85B antigen .
