OR51I2 Antibody

What is OR51I2 and why is it targeted in research?

OR51I2 (Olfactory Receptor Family 51, Subfamily I, Member 2) is a G protein-coupled receptor originally identified in olfactory neurons. Recent research has revealed its ectopic expression in non-olfactory tissues, which has increased interest in its potential roles beyond olfaction. The protein is encoded by the OR51I2 gene in humans and has been identified as potentially significant in various physiological and pathological processes. Targeting OR51I2 with antibodies allows researchers to study its expression patterns, protein interactions, and functional significance in both normal cellular processes and disease states .

What types of OR51I2 antibodies are available and how are they validated?

OR51I2 antibodies are primarily available as polyclonal antibodies derived from rabbits, targeting specific regions such as the C-terminus or internal regions of the protein. These antibodies undergo validation through Western blot analysis to confirm their specificity and reactivity. Most commercial antibodies use synthetic peptides directed towards specific regions of human OR51I2 as immunogens to generate the antibody response. Validation typically includes cross-reactivity testing with samples from multiple species, with some antibodies showing predicted reactivity across human (100%), cow (93%), dog (100%), guinea pig (86%), horse (100%), mouse (100%), pig (92%), rabbit (100%), and rat (100%) samples .

What is the difference between OR51I2 and OR51E2 antibodies?

While both target olfactory receptors from the same family (family 51), they recognize different subfamily members. OR51I2 antibodies target the Olfactory Receptor Family 51 Subfamily I Member 2, while OR51E2 antibodies target the Subfamily E Member 2. OR51E2 (also known as PSGR in some contexts) is a 35.5 kilodalton protein that has been more extensively studied, particularly in prostate tissues. The two receptors have distinct amino acid sequences, tissue distribution patterns, and potentially different functional roles, making it crucial not to use them interchangeably in research applications .

What applications are OR51I2 antibodies validated for?

OR51I2 antibodies are primarily validated for Western Blotting (WB) applications, with many also showing utility in ELISA, Immunofluorescence (IF), and Immunocytochemistry (ICC) techniques. The specific applications vary between different antibody products, with some optimized for particular techniques. Most commonly, researchers use these antibodies to detect protein expression in cell lysates, tissue sections, or immunoprecipitates. For optimal results, it's recommended to determine the working dilution specific to your experimental conditions and sample types .

How should I design experiments to study OR51I2 expression across different tissues?

When studying OR51I2 expression across different tissues, implement a multi-method approach combining:

• Western blot analysis: Use standardized protein extraction protocols across tissues, with equal loading (20-50 μg total protein) confirmed by housekeeping controls (β-actin or GAPDH).

• RT-qPCR: Design primers specific to OR51I2 mRNA (avoiding cross-reactivity with other OR family members).

• Immunohistochemistry/Immunofluorescence: Include positive and negative tissue controls known to express or lack OR51I2.

• Controls: Always include tissue samples from OR51I2 knockout models (when available) or validated positive controls.

For multi-tissue analysis, consider using tissue microarrays with your validated OR51I2 antibody to efficiently screen multiple samples simultaneously. Remember that olfactory receptors often show low expression levels in non-olfactory tissues, so sensitive detection methods may be necessary .

What are the optimal conditions for Western blotting with OR51I2 antibodies?

For optimal Western blotting with OR51I2 antibodies, follow these technical guidelines:

• Sample preparation: Use RIPA buffer with protease inhibitors for extraction; avoid repeated freeze-thaw cycles.

• Protein amount: Load 25-50 μg of total protein per lane.

• Gel percentage: Use 10-12% SDS-PAGE gels for optimal separation.

• Transfer conditions: Semi-dry transfer at 15V for 30 minutes or wet transfer at 100V for 1 hour.

• Blocking: 5% non-fat dry milk or BSA in TBST for 1 hour at room temperature.

• Primary antibody: Dilute OR51I2 antibody 1:500 to 1:1000 in blocking buffer; incubate overnight at 4°C.

• Washing: 3x10 minutes with TBST.

• Secondary antibody: Anti-rabbit HRP-conjugated at 1:5000 for 1 hour at room temperature.

• Detection: Enhanced chemiluminescence with exposure times adjusted based on signal strength.

Always include positive controls and optimize blocking conditions to reduce background if non-specific bands appear. Given the hydrophobic nature of olfactory receptors, membrane preparation protocols may need optimization to efficiently extract the protein .

How can I verify the specificity of OR51I2 antibody binding in my experiments?

To verify OR51I2 antibody specificity, implement these validation strategies:

• Peptide competition assay: Pre-incubate the antibody with excess immunizing peptide (5-10x molar concentration) before application to your samples. Signal disappearance confirms specific binding.

• Knockout/knockdown controls: Use CRISPR-Cas9 knockout or siRNA knockdown samples to confirm antibody specificity.

• Multiple antibodies approach: Compare staining patterns using antibodies targeting different epitopes of OR51I2 (e.g., N-terminal vs. C-terminal).

• Recombinant protein control: Express tagged recombinant OR51I2 in a cell line and confirm detection by both the OR51I2 antibody and an antibody against the tag.

• Cross-reactivity assessment: Test the antibody on samples from species with known sequence homology percentages (cow: 93%, dog: 100%, guinea pig: 86%, etc.) to confirm predicted reactivity patterns .

What considerations are important when using OR51I2 antibodies for immunofluorescence?

When using OR51I2 antibodies for immunofluorescence applications, consider these critical factors:

• Fixation method: Test both paraformaldehyde (4%, 10-15 minutes) and methanol (-20°C, 10 minutes) fixation, as membrane proteins like OR51I2 may show differential epitope accessibility.

• Permeabilization: Use 0.1-0.3% Triton X-100 for 5-10 minutes; over-permeabilization can disrupt membrane protein structure.

• Blocking: Extended blocking (2 hours, room temperature) with 3-5% normal serum from the secondary antibody host species with 0.1% Tween-20.

• Antibody concentration: Start with 1:100-1:200 dilution and titrate as needed.

• Incubation conditions: Overnight at 4°C in humidified chamber for primary antibody.

• Controls: Include peptide competition and secondary-only controls on the same slide.

• Auto-fluorescence reduction: Consider treatment with 0.1% Sudan Black in 70% ethanol after secondary antibody incubation to reduce background, particularly in tissues with high lipid content.

• Co-localization studies: Pair with markers of specific cellular compartments to confirm expected subcellular localization of this 7-transmembrane receptor .

How can OR51I2 antibodies be used to investigate potential roles in cancer research?

OR51I2 antibodies can be strategically employed in cancer research through several advanced approaches:

• Tissue microarray analysis: Systematically examine OR51I2 expression across cancer progression stages and correlate with clinical outcomes. Analyze using automated quantification systems for unbiased assessment.

• Co-immunoprecipitation studies: Identify protein interaction partners in cancer cells by using OR51I2 antibodies for pull-down experiments followed by mass spectrometry analysis.

• ChIP-seq applications: If investigating transcriptional regulation, OR51I2 antibodies can be adapted for chromatin immunoprecipitation to identify genomic binding sites.

• Proximity ligation assays: Combine OR51I2 antibodies with antibodies against suspected interaction partners to visualize and quantify protein-protein interactions in situ.

• Patient-derived xenograft models: Use immunohistochemistry with OR51I2 antibodies to track receptor expression changes in response to therapeutic interventions.

Similar to other olfactory receptors that have shown relevance in cancer biology (like OR51E2 in colorectal cancer), OR51I2 may serve as a potential biomarker or therapeutic target in specific cancer types .

What approaches can be used to correlate OR51I2 expression with functional outcomes in cell models?

To establish correlations between OR51I2 expression and functional outcomes in cellular models, implement these methodological approaches:

• Inducible expression systems: Create stable cell lines with doxycycline-inducible OR51I2 expression to enable precise control over expression levels and timing.

• Calcium imaging: Given the G protein-coupled receptor nature of OR51I2, monitor intracellular calcium flux following potential ligand exposure using fluorescent calcium indicators.

• cAMP assays: Measure changes in cyclic AMP levels using ELISA or FRET-based reporters to assess receptor activation.

• Migration/invasion assays: Correlate OR51I2 expression levels (confirmed by the antibody) with phenotypic changes in cell behavior using wound healing, transwell, or 3D invasion assays.

• Signaling pathway analysis: Use phospho-specific antibodies to examine downstream effectors (e.g., MAPK, PI3K/Akt pathways) in relation to OR51I2 expression levels.

• Single-cell analysis: Combine OR51I2 immunostaining with functional readouts at the single-cell level to account for heterogeneity in receptor expression.

These approaches should include appropriate controls, including cells with CRISPR-mediated OR51I2 knockout or siRNA knockdown, with expression levels verified using the OR51I2 antibody .

How can I optimize co-immunoprecipitation protocols for OR51I2 protein interaction studies?

Optimizing co-immunoprecipitation for OR51I2 protein interaction studies requires consideration of its transmembrane nature:

• Lysis buffer optimization:

  • Use mild detergents like 1% NP-40 or 0.5% CHAPS to maintain protein-protein interactions

  • Include protease inhibitors, phosphatase inhibitors, and 150-300 mM NaCl

  • Consider crosslinking with DSP (2 mM, 30 min at room temperature) before lysis

• Pre-clearing step:

  • Incubate lysate with Protein A/G beads for 1 hour at 4°C

  • Remove beads to reduce non-specific binding

• Antibody incubation:

  • Use 2-5 μg of affinity-purified OR51I2 antibody per 500 μg of protein

  • Incubate overnight at 4°C with gentle rotation

• Bead selection and washing:

  • Magnetic beads often yield cleaner results than agarose beads

  • Perform 5 washes with decreasing salt concentration (from 300 mM to 150 mM)

  • Include 0.1% detergent in wash buffers

• Elution and detection:

  • Elute with low pH glycine buffer or SDS sample buffer

  • Analyze interacting proteins by Western blot or mass spectrometry

• Controls:

  • Include IgG control immunoprecipitation

  • Validate interactions with reciprocal co-IP when possible

  • Consider size-exclusion chromatography as a complementary approach

How should I address potential cross-reactivity when interpreting OR51I2 antibody results?

When addressing potential cross-reactivity in OR51I2 antibody experiments, implement this systematic framework:

• Sequence homology analysis:

  • Perform BLAST analysis of the immunizing peptide against the proteome

  • Create a table of proteins with >70% sequence identity to the epitope region

  • Pay particular attention to other OR family members with high homology

• Multiple antibody validation:

  • Compare results from antibodies targeting different epitopes of OR51I2

  • Document consistent vs. inconsistent staining patterns

• Transcript correlation:

  • Correlate protein detection with mRNA expression data (qPCR or RNA-seq)

  • Discrepancies may indicate cross-reactivity

• Knockout controls:

  • Always include genetic knockout samples when possible

  • For human samples, utilize CRISPR-modified cell lines

• Heterologous expression systems:

  • Express OR51I2 in systems with minimal endogenous expression

  • Test antibody specificity in this controlled context

• Systematic dilution series:

  • Perform antibody dilution series to identify the optimal signal-to-noise ratio

  • Document how patterns change with concentration

When publishing results, transparently document these validation steps and include a table of predicted cross-reactivity based on sequence homology percentages (cow: 93%, dog: 100%, guinea pig: 86%, etc.) .

What statistical approaches are recommended for quantifying OR51I2 expression differences across experimental groups?

For rigorous quantification of OR51I2 expression differences across experimental groups, implement these statistical best practices:

• Sample size determination:

  • Perform power analysis before experiments

  • For Western blots: minimum n=4 biological replicates

  • For immunohistochemistry: minimum 5-10 independent samples per group with multiple fields per sample

• Normalization approaches:

  • Western blot: Normalize to total protein (Ponceau S) rather than single housekeeping proteins

  • Immunofluorescence: Use ratio to nuclear stain or another stable marker

• Quantification methods:

  • Western blot: Use dynamic range-appropriate exposure and validated quantification software

  • Immunofluorescence: Employ automated thresholding algorithms with blind analysis

• Statistical tests:

  • For normally distributed data: ANOVA with appropriate post-hoc tests

  • For non-normally distributed data: Kruskal-Wallis with Dunn's post-hoc

  • For correlation analyses: Spearman's rank correlation

• Reporting standards:

  • Include representative images of all data points

  • Report all exclusion criteria and outlier handling

  • Present data as box plots showing distribution rather than bar graphs

• Multi-dimensional analysis:

  • Consider multivariate approaches when examining OR51I2 in relation to other markers

  • Use principal component analysis for complex datasets

These approaches ensure reproducible and statistically sound quantification of OR51I2 expression differences .

How can I distinguish between specific OR51I2 signal and background in challenging tissue samples?

Distinguishing specific OR51I2 signal from background in challenging tissues requires multifaceted approaches:

• Advanced blocking strategies:

  • Sequential blocking: 1 hour with 5% BSA followed by 1 hour with 5% normal serum

  • Addition of 0.1-0.3% Triton X-100 to blocking buffer

  • Consider adding 5% non-fat dry milk to reduce hydrophobic interactions

• Signal amplification with controls:

  • Tyramide signal amplification can increase sensitivity

  • Always run parallel amplification on negative control samples

• Multi-spectral imaging:

  • Use spectral unmixing to separate true signal from autofluorescence

  • Capture autofluorescence spectra from unstained samples

• Titration series validation:

  • Perform detailed antibody dilution series (1:50 to 1:1000)

  • Document how signal-to-noise ratio changes across concentrations

• Complementary detection methods:

  • Validate with RNA in situ hybridization on serial sections

  • Compare chromogenic vs. fluorescent detection methods

• Digital image analysis protocols:

  • Implement computational background subtraction

  • Use machine learning algorithms trained on validated positive/negative controls

• Antigen retrieval optimization table:

  Method	Temperature	Duration	Buffer	Best For
  Heat-mediated	95°C	20 min	Citrate pH 6.0	FFPE samples
  Heat-mediated	95°C	20 min	Tris-EDTA pH 9.0	Heavily fixed tissues
  Enzymatic	37°C	10 min	Proteinase K	Fresh frozen sections
  No retrieval	-	-	-	Methanol-fixed cells

These approaches should be systematically documented when reporting results with OR51I2 antibodies in challenging tissues .

What are the best approaches for reproducing OR51I2 antibody results across different laboratories?

To ensure reproducibility of OR51I2 antibody experiments across laboratories, implement these standardization protocols:

• Detailed antibody documentation:

  • Create a comprehensive table with catalog number, lot number, clonality, host, immunogen sequence

  • Document storage conditions and any freeze-thaw cycles

  • Record date of first use and calibration experiments

• Protocol standardization:

  • Develop explicit step-by-step protocols with exact buffer compositions

  • Include timing, temperature, and equipment specifications

  • Create troubleshooting decision trees for common issues

• Positive control distribution:

  • Share positive control lysates or slides between laboratories

  • Distribute recombinant OR51I2 protein standards when possible

• Antibody validation consortium:

  • Implement multi-site testing of the same antibody lot

  • Document variation in results across different handlers and equipment

• Digital image standardization:

  • Use consistent acquisition parameters

  • Share raw image files rather than processed images

  • Implement standardized quantification macros

• Detailed methods reporting checklist:

  Parameter	Required Documentation
  Antibody source	Catalog #, lot #, RRID identifier
  Dilution	Exact dilution and diluent composition
  Incubation	Time, temperature, container type
  Washing	Buffer composition, number of washes, duration
  Controls	Full description of all controls
  Analysis	Software, version, parameters, thresholds

Following these practices ensures that OR51I2 antibody results can be faithfully reproduced across different research environments .

How might single-cell technologies enhance our understanding of OR51I2 expression and function?

Single-cell technologies offer transformative approaches for OR51I2 research:

• Single-cell RNA sequencing applications:

  • Reveal cell-type specific expression patterns of OR51I2 across tissues

  • Identify co-expression networks that suggest functional pathways

  • Map temporal dynamics during development or disease progression

• Mass cytometry (CyTOF) integration:

  • Combine OR51I2 antibodies with dozens of other markers

  • Create high-dimensional phenotypic maps of OR51I2-expressing cells

  • Correlate expression with functional markers at single-cell resolution

• Spatial transcriptomics correlation:

  • Integrate OR51I2 antibody staining with spatial transcriptomics

  • Map receptor expression to precise tissue microenvironments

  • Correlate with gene expression programs in the same tissue section

• Live-cell imaging approaches:

  • Monitor real-time trafficking of fluorescently-tagged OR51I2

  • Assess dynamic responses to potential ligands

  • Correlate with functional readouts in the same cells

• Single-cell proteomics integration:

  • Apply antibody-based single-cell proteomics to quantify OR51I2

  • Correlate with signaling pathway activation markers

  • Create protein-protein interaction maps at single-cell resolution

These technologies overcome limitations of bulk analysis methods and can reveal heterogeneity in OR51I2 expression and function that may be critical for understanding its biological roles .

What techniques should be considered for investigating potential OR51I2 ligands and signaling mechanisms?

For investigating OR51I2 ligands and signaling pathways, consider these specialized techniques:

• High-throughput ligand screening platforms:

  • FLIPR-based calcium mobilization assays with OR51I2-expressing cells

  • BRET/FRET-based G-protein activation assays

  • Label-free dynamic mass redistribution assays

  • Design screening libraries based on structural similarities to known olfactory receptor ligands

• Signaling pathway deconvolution:

  • Phosphoproteomic analysis following receptor activation

  • G-protein subtype identification using pathway-specific inhibitors

  • Real-time cAMP or IP3 biosensors to determine signaling kinetics

  • RNA-seq to identify transcriptional signatures of activation

• Structure-function analyses:

  • Site-directed mutagenesis of predicted binding pocket residues

  • Chimeric receptor approaches with other characterized olfactory receptors

  • Computational modeling of ligand docking

  • Molecular dynamics simulations of receptor-ligand interactions

• Validation in physiologically relevant models:

  • Confirm ligand responses in native tissue preparations

  • Develop tissue-specific OR51I2 knockout models

  • Use in vivo calcium imaging in genetically modified organisms

  • Correlate ex vivo responses with in vivo phenotypes

These approaches should be implemented systematically, with appropriate controls and validation steps to ensure the specificity of observed responses to OR51I2 activation .