SPAC23H4.21 Antibody is a polyclonal antibody raised against the Sup11 protein encoded by the sup11+ gene (SPAC23H4.21 locus) in S. pombe. Sup11p shares homology with Saccharomyces cerevisiae Kre9, a protein implicated in β-1,6-glucan synthesis . The antibody detects Sup11p’s expression and localization, enabling researchers to investigate its role in cell wall biogenesis and septum formation during yeast cell division .
Essential Gene: sup11+ is indispensable for cell viability. Depletion results in lethal morphological defects, including malformed septa and aberrant cell wall deposition .
β-1,6-Glucan Synthesis: Sup11p is critical for β-1,6-glucan formation. Mutants lacking functional Sup11p show complete absence of β-1,6-glucan in cell walls, leading to compromised structural integrity .
Septum Formation: Sup11p depletion causes excessive accumulation of β-1,3-glucan at the septum center, disrupting normal cell separation .
Genetic Interactions: sup11+ interacts with β-1,6-glucanase genes (e.g., agn1+, gas2+), which are upregulated during Sup11p depletion to compensate for cell wall defects .
Transcriptional Regulation: Microarray analysis revealed significant changes in gene expression related to glucan metabolism, including:
| Gene | Function | Regulation (Fold Change) |
|---|---|---|
| gas2+ | β-1,3-glucanosyltransferase | ↑ 4.2 |
| agn1+ | Endo-β-1,3-glucanase | ↑ 3.8 |
| cwf16+ | Cell wall glucanase | ↑ 2.5 |
| Data derived from transcriptome analysis of nmt81-sup11 mutants . |
SPAC23H4.21 Antibody has been utilized in multiple methodologies:
Western Blotting: Detects Sup11p expression levels under varying genetic or environmental conditions .
Immunolocalization: Visualizes Sup11p’s subcellular distribution, confirming its association with the endoplasmic reticulum and Golgi apparatus .
Functional Studies: Validates sup11+ knockout phenotypes, including septum malformation and cell wall composition changes .
Specificity: The antibody recognizes both native and denatured forms of Sup11p, with cross-reactivity validated via immunoblotting .
Glycosylation Impact: Sup11p’s glycosylation status affects antibody binding. Hypo-O-mannosylated variants exhibit altered migration patterns in SDS-PAGE .
Findings from studies using SPAC23H4.21 Antibody have advanced understanding of fungal cell wall dynamics, offering insights into analogous processes in pathogenic fungi and potential therapeutic targets. For example, dysregulated β-glucan synthesis pathways are relevant to antifungal drug development .
When performing IHC with SPAC23H4.21 antibody, optimal results typically require paraformaldehyde fixation followed by paraffin embedding (IHC-P). The recommended protocol includes:
Fix tissue with 4% formaldehyde for 24-48 hours
Block endogenous peroxidase activity with 1% BSA for 10 minutes at room temperature (21°C)
Perform heat-mediated antigen retrieval using citric acid buffer (pH 6.0)
Incubate with primary SPAC23H4.21 antibody at 1:500 dilution in TBS/BSA/azide for 2 hours at 21°C
Detect using a biotin-conjugated secondary antibody appropriate for the host species
This approach provides consistent staining patterns across multiple tissue types while minimizing background signal .
Current validation data for SPAC23H4.21 antibody demonstrates utility in multiple applications:
Immunohistochemistry (IHC-P) on paraformaldehyde-fixed tissues
Immunofluorescence (IF) for cellular localization studies
Western blotting (WB) for protein expression analysis
The antibody has been tested with positive results across human, mouse, and rat samples, with conservation of binding patterns suggesting consistent epitope recognition across species. Each application requires specific optimization, with IF typically requiring lower antibody concentrations (1:1000) compared to IHC applications .
Proper storage of SPAC23H4.21 antibody is critical for maintaining its binding efficiency and specificity. The recommended storage conditions are:
Store at -20°C for long-term stability
Aliquot upon first thaw to avoid repeated freeze-thaw cycles
For working solutions, store at 4°C for up to one month
Add preservatives such as sodium azide (0.02%) for solutions stored at 4°C
Monitor solution clarity; cloudiness may indicate degradation
Antibody stability can be verified through periodic testing against known positive controls. Significant loss in signal intensity (>20%) indicates potential degradation requiring fresh antibody preparation .
Comprehensive validation of SPAC23H4.21 antibody specificity requires a multi-platform approach:
Peptide competition assays: Pre-incubate antibody with purified antigen peptide before application to samples; complete signal blocking confirms specificity
Genetic knockdown validation: Compare staining in wild-type versus SPAC23H4.21 knockdown/knockout models
Cross-platform concordance: Compare results across IHC, IF, and WB to confirm consistent target recognition
Mass spectrometry validation: Immunoprecipitate with SPAC23H4.21 antibody and confirm pulled-down proteins via MS
Inter-antibody comparison: Test multiple antibodies against the same target to establish consensus detection patterns
These approaches collectively establish confidence in antibody specificity, with documentation of validation experiments essential for publication-quality research .
Determining optimal antibody concentration for SPAC23H4.21 immunofluorescence requires systematic titration:
Prepare serial dilutions (1:100, 1:500, 1:1000, 1:2000, 1:5000) of antibody
Apply to identical positive control samples under consistent conditions
Quantify both target signal intensity and background noise using digital image analysis
Calculate signal-to-noise ratio (SNR) for each concentration
Select concentration that maximizes SNR while minimizing antibody consumption
Typically, a 1:500 to 1:1000 dilution provides optimal results for most research-grade antibodies in IF applications. Additionally, incorporating a detergent like 0.1% Triton X-100 during incubation can further reduce background signal while maintaining specific binding .
When facing contradictory results between detection methods (e.g., positive IHC but negative Western blot), a systematic troubleshooting approach is required:
Epitope accessibility analysis: Different methods expose different protein conformations; native versus denatured states may affect antibody binding
Protocol optimization: Adjust fixation methods, antigen retrieval, or blocking conditions for each technique
Antibody validation: Confirm antibody specificity using knockout controls or competing antibodies
Target expression levels: Consider threshold detection differences between methods
Post-translational modifications: Determine if the epitope undergoes modifications that affect antibody recognition
Robust experimental design for SPAC23H4.21 antibody research requires multiple control types:
| Control Type | Implementation | Purpose |
|---|---|---|
| Positive Control | Known expressing tissue/cell | Confirms antibody activity |
| Negative Control | Non-expressing tissue/cell | Establishes background levels |
| Isotype Control | Non-specific antibody of same isotype | Detects non-specific binding |
| No Primary Control | Secondary antibody only | Identifies secondary antibody artifacts |
| Absorption Control | Antibody pre-incubated with target | Confirms epitope specificity |
| Technical Replicates | Repeated staining of same sample | Assesses staining reproducibility |
| Biological Replicates | Independent biological samples | Confirms biological consistency |
Inclusion of these controls enables confident interpretation of results by distinguishing specific from non-specific signals and establishing result reproducibility .
Developing a standardized protocol for SPAC23H4.21 antibody across different platforms requires systematic optimization and validation:
Begin with manufacturer's recommended protocol as baseline
Test on multiple platforms (e.g., Dako ASL48, VENTANA BenchMark ULTRA, Leica Bond-III)
Adjust key variables independently:
Antibody concentration
Incubation time and temperature
Antigen retrieval method
Detection system
Evaluate staining using quantitative metrics (e.g., H-score, TPS)
Perform statistical concordance analysis between platforms
Document protocol variations required for equivalence
Aim for positive percentage agreement (PPA) and negative percentage agreement (NPA) values >90% between platforms. Complete documentation of platform-specific adjustments ensures standardization across research sites .
When analyzing heterogeneous tissues with SPAC23H4.21 antibody, sample selection and processing significantly impact result interpretation:
Spatial heterogeneity: Sample multiple regions (minimum 3-5) within tissue to capture spatial variation
Temporal considerations: For dynamic processes, establish consistent timepoints for sample collection
Sample thickness optimization: 4-5μm sections typically provide optimal resolution while maintaining structural integrity
Batch processing: Process experimental and control samples simultaneously to minimize technical variation
Quantification strategy: Define representative fields (minimum 5-10) for quantitative analysis
Cell-type specific analysis: Consider dual-staining approaches to identify cell subpopulations
These considerations ensure that observed patterns reflect true biological variation rather than sampling artifacts, particularly important when target expression shows spatial heterogeneity .
Robust quantification of SPAC23H4.21 staining requires established scoring systems and digital analysis:
Manual scoring systems:
H-score: Combines intensity (0-3) and percentage of positive cells (0-100%)
Tumor Proportion Score (TPS): Percentage of positive cells regardless of intensity
Allred score: Combines intensity (0-3) and proportion scores (0-5)
Digital image analysis workflow:
Capture high-resolution images using standardized microscope settings
Perform color deconvolution to separate chromogens
Apply thresholding to distinguish positive from negative staining
Quantify staining intensity using integrated optical density
Report both percentage positive cells and staining intensity
Statistical analysis:
Apply appropriate statistical tests based on data distribution
Report interobserver concordance for manual scoring (kappa statistic)
Include measures of technical reproducibility
For research purposes, combining both methods provides comprehensive assessment while acknowledging the limitations of each approach .
Addressing batch-to-batch variability in SPAC23H4.21 antibody staining requires systematic investigation of multiple factors:
Antibody-related factors:
Check antibody lot consistency and consider single-batch purchasing
Verify antibody storage conditions and freeze-thaw cycles
Re-validate antibody specificity using positive controls
Sample-related factors:
Standardize fixation time and conditions
Monitor tissue processing parameters (dehydration, clearing, embedding)
Implement consistent sectioning techniques
Protocol-related factors:
Use automated platforms when possible to reduce handling variation
Prepare fresh reagents consistently
Document environmental conditions (temperature, humidity)
Analysis-related factors:
Standardize image acquisition parameters
Implement blinded analysis
Use internal reference standards for normalization
Systematic documentation of these parameters enables identification of variation sources. Incorporating control samples across batches allows for normalization of results between experimental runs .
When unexpected cellular localization patterns emerge, several analytical approaches can resolve apparent contradictions:
Multi-technique verification:
Confirm localization using orthogonal methods (IF, IHC, subcellular fractionation)
Employ super-resolution microscopy for precise spatial resolution
Biological context analysis:
Investigate if localization changes under different physiological conditions
Examine temporal dynamics using time-course experiments
Consider cell-cycle dependent localization patterns
Epitope-specific considerations:
Determine if the epitope is masked in certain cellular compartments
Test multiple antibodies targeting different epitopes of the same protein
Investigate post-translational modifications affecting antibody recognition
Functional validation:
Employ proximity ligation assays to confirm protein-protein interactions
Use FRET/BRET to validate protein proximity in live cells
Correlate localization with functional readouts
Unexpected localization patterns often reveal novel biological insights rather than technical artifacts. Thorough documentation of these investigative approaches strengthens the scientific narrative when reporting novel localization patterns .
Contributing antibody validation data to community resources enhances scientific reproducibility through several structured approaches:
Database submission protocols:
Format validation data according to PLAbDab submission guidelines
Include paired antibody sequences when available
Document experimental conditions comprehensively
Provide structural models where applicable
Required metadata elements:
Detailed experimental protocols
Positive and negative control documentation
Cross-platform validation results
Species cross-reactivity data
Data standardization considerations:
Use standardized ontologies for tissue and cell types
Implement RRID (Research Resource Identifiers) for antibody tracking
Follow MIAPAR (Minimum Information About a Protein Affinity Reagent) guidelines
Collaborative data sharing significantly enhances the research community's ability to select appropriate antibodies and design robust experiments, ultimately reducing resource waste and accelerating scientific discovery .
Computational approaches provide valuable insights for predicting antibody behavior before experimental validation:
Epitope prediction tools:
Sequence-based B-cell epitope prediction algorithms
Structural epitope mapping using molecular modeling
Conservation analysis across orthologs for evolutionary constraints
Cross-reactivity assessment:
BLAST analysis against proteome databases to identify similar epitopes
Molecular docking to model antibody-antigen interactions
Machine learning approaches trained on antibody binding data
Structural prediction resources:
ABodyBuilder2 for antibody structural modeling
Molecular dynamics simulations to assess binding stability
Conformational epitope analysis for discontinuous epitopes
These computational approaches can guide experimental design by identifying potential cross-reactive targets and optimizing antibody selection, particularly valuable when working with novel targets or minimal validation data .