Both antibodies target the full-length human C16orf78 protein (265 amino acids, 31 kDa) and show no cross-reactivity with non-human species .
C16orf78 is a nuclear protein encoded by a gene at 16q12.1. Key features include:
Structural Properties: Predominantly α-helical with coiled-coil domains, though structural predictions remain low-confidence .
Post-Translational Modifications: Contains 4 ubiquitination and 3 phosphorylation sites, with phosphorylation by SRPK1/SPRK2 kinases .
Interactions: Binds KIN17, a DNA/RNA-binding protein involved in DNA repair .
Tissue Specificity: Highly expressed in the testis, minimal in other tissues .
Subcellular Localization: Nuclear, with a bipartite nuclear localization signal .
C16orf78 antibodies are used to:
Map Protein Expression: Identify tissue-specific expression via IHC (e.g., adrenal gland studies ).
Study Post-Translational Modifications: Detect phosphorylation/ubiquitination states in cancer models .
Investigate Protein Interactions: Co-immunoprecipitation with KIN17 or kinase assays with SRPK1/SPRK2 .
C16orf78 has been implicated in:
Prostate Cancer: A SNP in C16orf78 interacts with LMTK2 to increase risk, while gene deletions are linked to aggressive subtypes .
Metabolic Adaptation: Amplifications correlate with metabolic flexibility in cancer cells .
C16orf78 shows evolutionary conservation across vertebrates and invertebrates, with notable divergence:
| Species | Divergence (Mya) | % Identity | % Similarity |
|---|---|---|---|
| Gorilla | 9.06 | 96 | 98 |
| Mouse | 90 | 57 | 69 |
| Python (bivittatus) | 312 | 23 | 37 |
| Ciona (intestinalis) | 676 | 10 | 32 |
This conservation suggests a fundamental but poorly understood role in cellular processes .
C16orf78 (Chromosome 16 Open Reading Frame 78) is a human protein classified as having unknown function. It is primarily localized to the nucleus and is encoded by a gene located on chromosome 16q12.1 . While the complete functions of C16orf78 remain to be fully characterized, preliminary research suggests it may act as a potential regulator of gene expression . The protein has emerging roles in cellular processes that are still being investigated, with potential implications in cancer research and developmental biology .
For researchers beginning work with this protein, it's important to note that C16orf78 is also referred to as "Uncharacterized protein C16orf78" in scientific literature and databases, with the UniProt code Q8WTQ4 . Experimental approaches focusing on protein-protein interactions and subcellular localization studies may yield valuable insights into its biological roles.
When selecting a C16orf78 antibody, consider these key methodological factors:
Validation method: Prioritize antibodies validated using genetic approaches (knockout or knockdown controls) rather than only orthogonal methods. Studies show genetic validation strategies generate more robust characterization data, particularly for immunofluorescence applications .
Application compatibility: Verify the antibody has been specifically validated for your intended application. Currently available C16orf78 antibodies have been validated for Western blot applications , and some for immunohistochemistry , but validation for other applications may vary.
Clone type: Consider whether a polyclonal or monoclonal antibody better suits your research needs. Available C16orf78 antibodies include rabbit polyclonal options which offer high sensitivity but may have batch-to-batch variation.
Species reactivity: Confirm the antibody has been validated against your species of interest. Current C16orf78 antibodies show reactivity with human samples .
Renewable source: When possible, select recombinant antibodies as they represent the ultimate renewable reagent with advantages in terms of adaptability .
Based on current data, C16orf78 antibodies have been validated for the following applications:
The C16orf78 polyclonal antibody PACO39494 has been specifically validated in immunohistochemistry applications using paraffin-embedded human adrenal gland tissue at a dilution of 1:100 . For Western blot applications, the NBP1-56418 antibody has been validated to react with human samples .
Researchers should note that comprehensive validation data including knockout controls may not be available for all applications, and additional validation in your specific experimental system is recommended.
The gold standard for antibody validation employs genetic approaches using knockout (KO) or knockdown controls. Based on extensive antibody validation studies, follow this comprehensive validation methodology:
Establish appropriate cell models: Select cell lines that express detectable levels of C16orf78. For human protein targets including C16orf78, researchers typically use cell lines with RNA expression above 2(TPM+1) .
Generate knockout controls: Create CRISPR-Cas9 knockout cell lines or use RNAi knockdown (if C16orf78 is essential). These genetically modified cells serve as critical negative controls.
Implement side-by-side testing: Run samples from parental and KO/knockdown cells in adjacent lanes for Western blots or in the same visual field for immunofluorescence to reduce imaging and analysis biases .
Perform multi-application validation: Test the antibody in multiple applications (Western blot, immunoprecipitation, immunofluorescence) using standardized protocols to comprehensively assess specificity .
Evaluate cross-reactivity: Examine non-specific bands in Western blots or non-specific staining in immunofluorescence that persist in KO/knockdown samples.
Document validation rigorously: Record detailed validation data including images showing presence/absence of signal in control versus KO/knockdown samples, and specific experimental conditions used.
For researchers without access to knockout systems, orthogonal validation approaches can be employed, though these are less robust than genetic approaches, particularly for immunofluorescence applications .
Optimizing Western blot protocols for C16orf78 detection requires careful consideration of several parameters:
Sample preparation:
For nuclear proteins like C16orf78, use nuclear extraction protocols with protease inhibitors
Include phosphatase inhibitors if investigating potential post-translational modifications
Denature samples at 95°C for 5 minutes in reducing sample buffer
Gel selection and transfer:
Use 10-12% polyacrylamide gels for optimal resolution of C16orf78 (~30-40 kDa range)
Transfer to PVDF membranes at low voltage (30V) overnight at 4°C for efficient transfer of nuclear proteins
Blocking and antibody incubation:
Block with 5% non-fat dry milk in TBST for 1 hour at room temperature
Incubate with primary C16orf78 antibody at manufacturer's recommended dilution (typically between 1:500-1:2000 for Western blot)
Extend primary antibody incubation to overnight at 4°C for enhanced sensitivity
Use secondary antibody at 1:5000-1:10000 dilution
Detection optimization:
For low abundance proteins, consider using enhanced chemiluminescence (ECL) with longer exposure times
Include positive controls from tissues/cell lines known to express C16orf78
Controls:
Include knockout or knockdown samples as negative controls
Use recombinant C16orf78 protein as a positive control when available
Include molecular weight markers to confirm band size
Following these optimizations should improve detection specificity and sensitivity for C16orf78 in Western blot applications.
Investigating protein-protein interactions for poorly characterized proteins like C16orf78 presents several methodological challenges:
Low endogenous expression: C16orf78 may be expressed at low levels in many cell types, making detection of interaction partners difficult. Consider using cell lines with higher expression levels or overexpression systems carefully validated to maintain physiological interactions.
Nuclear localization complexity: As a nuclear protein , C16orf78 interactions may be context-dependent and influenced by chromatin state, making standard immunoprecipitation protocols less effective. Optimize lysis conditions to effectively solubilize nuclear proteins while maintaining native interactions.
Unknown interactome: With limited information about potential binding partners, unbiased approaches are necessary. Consider these methodologies:
Proximity-dependent biotin identification (BioID)
Affinity purification followed by mass spectrometry (AP-MS)
Yeast two-hybrid screening with a C16orf78 bait construct
Co-immunoprecipitation coupled with antibody arrays
Antibody specificity concerns: Validate antibody specificity rigorously before immunoprecipitation studies. For C16orf78, confirm the antibody effectively immunoprecipitates the target protein by Western blot detection of the immunoprecipitate .
Dynamic interactions: If C16orf78 participates in transient interactions, consider using crosslinking approaches (formaldehyde or DSS crosslinkers) prior to immunoprecipitation.
Validation of interactions: Confirm identified interactions through reciprocal co-immunoprecipitation and functional studies to establish biological relevance.
Given the limited characterization of C16orf78, researchers should design interaction studies with appropriate controls and multiple methodological approaches to establish confidence in identified interaction partners.
Non-specific binding is a common challenge with antibodies, particularly for less characterized proteins like C16orf78. Apply these methodological approaches to troubleshoot and minimize non-specific binding:
Validate antibody specificity:
Optimize blocking conditions:
Test different blocking agents (BSA, milk, commercial blockers)
Increase blocking time (2-4 hours) and concentration (5-10%)
Add 0.1-0.3% Triton X-100 to reduce hydrophobic interactions
Adjust antibody concentration:
Modify washing procedures:
Increase number and duration of washes
Use higher detergent concentration in wash buffers
Include salt in wash buffers (up to 500mM NaCl) to disrupt low-affinity interactions
Apply additional controls:
Include secondary-only controls to identify non-specific binding from secondary antibody
Use isotype controls to identify Fc receptor binding
Test pre-immune serum when available for polyclonal antibodies
For persistent non-specific binding, consider alternative antibody clones or suppliers, as antibody performance varies significantly among commercial sources .
Implementing appropriate controls is crucial for confident interpretation of C16orf78 antibody results:
Positive Controls:
Cell/tissue types with confirmed expression: Select cell lines or tissues with validated C16orf78 expression. Human adrenal gland tissue has been used successfully for IHC validation .
Recombinant protein controls: Use purified recombinant C16orf78 protein as a positive control for Western blot, particularly the human recombinant protein covering amino acids 1-265 .
Overexpression systems: Transiently transfect cells with C16orf78 expression constructs to create positive controls with high expression levels.
Negative Controls:
Genetic knockout/knockdown models: CRISPR-Cas9 knockout or siRNA knockdown cells provide the most rigorous negative controls .
Species without cross-reactivity: If using human-specific C16orf78 antibodies, non-human samples can serve as negative controls if sequence divergence eliminates antibody recognition.
Technical controls:
Primary antibody omission
Isotype controls (particularly for flow cytometry)
Peptide competition assays using the immunizing peptide
Comparative Controls:
Multiple antibody validation: Test multiple antibodies against C16orf78 side-by-side to identify consistent versus inconsistent signals .
Correlation with mRNA expression: Compare protein detection patterns with RNA-seq or qPCR data across multiple cell types.
Orthogonal detection methods: Confirm results using alternative approaches (e.g., mass spectrometry detection of immunoprecipitated proteins).
For publications, include images of both positive and negative controls alongside experimental samples to demonstrate antibody specificity .
Quantitative analysis of C16orf78 expression requires methodological rigor and appropriate controls. Follow these steps for reliable quantification:
Western Blot Quantification:
Include a standard curve of recombinant C16orf78 protein at known concentrations
Ensure linearity of detection within your sample range
Use housekeeping proteins or total protein stains (Ponceau S, REVERT) for normalization
Apply image analysis software (ImageJ, Image Studio) with background subtraction
Run technical and biological replicates (minimum n=3) for statistical analysis
Immunohistochemistry/Immunofluorescence Quantification:
Use standardized acquisition parameters (exposure time, gain)
Implement automated analysis algorithms to reduce subjectivity
Quantify signal intensity, subcellular distribution, and percent positive cells
Normalize to DAPI or other nuclear counterstains for nuclear proteins like C16orf78
Include knockout controls to establish background threshold levels
ELISA-Based Quantification:
Develop standard curves using recombinant C16orf78
Determine the optimal sample dilution within the linear range
Assess matrix effects from different sample types
Calculate intra- and inter-assay coefficients of variation
Flow Cytometry:
Use appropriate permeabilization for nuclear proteins
Establish negative gates using knockout controls
Report results as median fluorescence intensity (MFI)
Present data as fold change over control conditions
Data Integration:
Correlate protein levels with mRNA expression data
Compare multiple detection methods for cross-validation
Apply appropriate statistical tests based on data distribution
Report both absolute and relative expression changes
Regardless of the method used, always include validation data demonstrating antibody specificity, as quantification is only meaningful when the signal specifically represents C16orf78 .
C16orf78 antibodies can be leveraged for diverse research applications beyond standard protein detection:
Chromatin Immunoprecipitation (ChIP):
Proximity Ligation Assay (PLA):
Visualize and quantify protein-protein interactions in situ
Combine C16orf78 antibody with antibodies against suspected interaction partners
PLA signal indicates proteins are within 40nm proximity
Particularly valuable for nuclear proteins where co-localization alone is insufficient
Therapeutic Target Validation:
Assess C16orf78 expression in disease tissues using antibody-based techniques
Correlate expression with clinical outcomes
Evaluate potential as biomarker or therapeutic target
Protein Degradation Studies:
Track C16orf78 stability and turnover using pulse-chase experiments
Investigate ubiquitination and other post-translational modifications
Assess protein half-life under various cellular stresses
Single-Cell Analysis:
Incorporate C16orf78 antibodies into mass cytometry (CyTOF) panels
Study heterogeneity of expression across cell populations
Correlate with cell state markers
Visualization of Dynamic Processes:
Utilize antibodies against C16orf78 in live-cell imaging (when conjugated appropriately)
Track protein localization during cell cycle or differentiation
Combine with optogenetic approaches for functional studies
Each application requires rigorous validation of antibody specificity in the specific experimental context, ideally using knockout controls to confirm signal specificity .
Studying post-translational modifications (PTMs) of poorly characterized proteins like C16orf78 presents unique methodological challenges:
PTM-Specific Antibody Development and Validation:
Generating modification-specific antibodies requires synthesized peptides with the predicted modification
Validation requires comparing signal between wild-type and mutant protein (with modified residue substituted)
Phosphatase or deubiquitinase treatment should eliminate signal from phospho- or ubiquitin-specific antibodies
Include controls with PTM-inducing treatments versus inhibitors
Mass Spectrometry Approaches:
Optimize immunoprecipitation protocols to preserve labile modifications
Enrich for specific modifications (e.g., TiO₂ for phosphopeptides)
Use targeted MS approaches for low-abundance proteins like C16orf78
Compare modification profiles across different cellular conditions
Key Experimental Design Considerations:
Investigate multiple potential modifications (phosphorylation, ubiquitination, SUMOylation, etc.)
Include appropriate positive controls (known modified proteins)
Verify antibody specificity for the modified form of the protein
Assess modification dynamics under different cellular conditions
Functional Assessment of PTMs:
Generate site-specific mutants (e.g., S/T→A or K→R)
Compare localization, stability, and interaction profiles of wild-type versus mutant proteins
Assess impact on potential nuclear functions of C16orf78
Correlate modifications with specific cellular processes or stress responses
Technical Limitations:
Low endogenous expression may limit detection sensitivity
PTMs may occur on only a small fraction of the total protein pool
Multiple modifications may interact in complex ways
Antibody cross-reactivity with similar modified motifs on other proteins
Given the exploratory nature of C16orf78 PTM research, combining multiple technical approaches provides the most robust results, with mass spectrometry serving as the gold standard for identification of novel modification sites.
Contradictory results from different antibodies targeting the same protein are common and require systematic analysis:
Antibody Validation Assessment:
Epitope Analysis:
Determine epitope locations for each antibody when available
Different epitopes may be differentially accessible in various experimental conditions
Some epitopes may be masked by protein interactions or conformational changes
Post-translational modifications may affect epitope recognition
Systematic Comparative Testing:
Test all antibodies side-by-side using identical protocols
Include positive and negative controls for each antibody
Systematically vary experimental conditions to identify variables affecting results
Document all conditions precisely to enable troubleshooting
Resolution Strategies:
Generate additional controls (e.g., overexpression, CRISPR-tagged endogenous protein)
Use orthogonal detection methods not reliant on antibodies
Consider antibody format (polyclonal vs. monoclonal) in interpretation
Consult literature for known issues with specific antibodies
Data Reporting:
Transparently report contradictory results in publications
Provide complete methodology and antibody validation data
Discuss potential reasons for discrepancies
Consider the possibility that both results may be correct under different conditions
Research on antibody validation has shown that for a single protein target, antibody performance can vary dramatically across manufacturers and lots . Side-by-side testing using standardized protocols and genetic controls provides the most reliable approach to resolve contradictions.
When analyzing C16orf78 expression data, employ these statistical approaches for robust interpretation:
For all statistical analyses, clearly document software, packages, and versions used, and consider consulting with a biostatistician for complex study designs. Given the exploratory nature of C16orf78 research, balance hypothesis testing with exploratory data analysis approaches.