The At4g13955 gene in Arabidopsis thaliana encodes a protein of uncharacterized function. While no direct studies on this protein were identified in the reviewed literature, its gene locus (At4g13955) suggests involvement in plant-specific processes, potentially:
Developmental regulation: Many Arabidopsis genes with similar nomenclature participate in growth or stress responses.
Metabolic pathways: Possible roles in secondary metabolism or signaling.
Note: Functional data for At4g13955 remains sparse, highlighting a gap in current plant proteomics research .
Though peer-reviewed studies specifically using the At4g13955 antibody are absent from the analyzed sources, its utility can be inferred from broader antibody use cases in plant biology:
Western blotting: Detect protein expression in transgenic or mutant Arabidopsis lines.
Immunohistochemistry: Localize At4g13955 protein in plant tissues (e.g., roots, leaves).
Knockout validation: Confirm gene silencing or CRISPR-edited mutations.
General antibody functions cited: antigen detection, protein quantification, and cellular localization .
Specificity: Requires empirical validation via controls (e.g., knockout Arabidopsis lines).
Cross-reactivity: No data on cross-reactivity with homologs in other plant species.
Storage: Likely stable at -20°C long-term, with aliquoting recommended to preserve activity .
Critical unanswered questions include:
Protein function: Biochemical assays to determine enzymatic or structural roles.
Expression patterns: Spatial/temporal profiling across Arabidopsis tissues.
Interaction networks: Identification of binding partners via immunoprecipitation.
KEGG: ath:AT4G13955
STRING: 3702.AT4G13955.1
At4g13955 antibodies can be effectively utilized in various detection methods, with Western blotting (WB) and ELISA being the most commonly applied techniques. For optimal results in Western blotting, a dilution range of 1:1000-3000 is typically recommended, similar to standard practices for polyclonal antibodies . When designing experiments, it's important to consider that detection sensitivity varies by method:
| Detection Method | Typical Dilution | Sensitivity Level | Sample Preparation Considerations |
|---|---|---|---|
| Western Blot | 1:1000-3000 | Moderate to High | Denaturing conditions required |
| ELISA | 1:1000-2000 | High | Native protein preferred |
| Immunofluorescence | 1:500-1000 | Variable | Fixation method critical |
For plant protein detection specifically, modifications to standard protocols may be necessary to address plant-specific interferents such as phenolic compounds and polysaccharides.
Proper storage is critical for maintaining antibody effectiveness. At4g13955 antibodies, like most research antibodies, should be stored at -20°C for long-term stability . The typical formulation includes phosphate buffered saline (pH 7.4) with 150mM NaCl, 0.02% sodium azide, and 50% glycerol as a cryoprotectant . Under these conditions, antibody activity generally remains stable for approximately 12 months from receipt date. Avoid repeated freeze-thaw cycles, which can significantly reduce antibody performance through formation of protein aggregates and denaturation events.
When validating antibody specificity for At4g13955, several controls are essential:
Positive control: Tissue or cell types known to express At4g13955 (typically Arabidopsis leaf or root tissues)
Negative control: Samples from knockout/knockdown plants lacking At4g13955 expression
Pre-absorption control: Antibody pre-incubated with purified antigen to confirm binding specificity
Secondary antibody-only control: To identify potential non-specific binding of the secondary detection system
These controls collectively allow researchers to differentiate between specific signal and background noise, a critical step in antibody validation that should precede experimental applications .
Recent advances in antibody engineering have demonstrated that sequence-based prediction models can significantly enhance antibody design. Models like DyAb can predict binding affinity changes (ΔpKD) resulting from specific amino acid substitutions in complementarity-determining regions (CDRs) . For At4g13955 antibody development, such approaches can be particularly valuable when:
Improving binding specificity to distinguish At4g13955 from closely related plant proteins
Enhancing affinity to detect low-abundance target proteins in plant tissues
Optimizing antibody performance across multiple detection platforms
The implementation involves selecting mutations that individually improve binding affinity, combining them to generate new sequences, and then scoring these sequences using computational models to predict performance improvements . This iterative approach has demonstrated success rates of 85-89% for expressing functional antibodies with improved binding characteristics .
Detecting post-translational modifications (PTMs) of At4g13955 presents several challenges that require specialized antibody approaches:
Modification-specific antibodies must recognize both the protein backbone and the specific modification
Plant proteins often exhibit species-specific or tissue-specific modification patterns
Low abundance of modified protein forms requires highly sensitive detection methods
A methodological approach to addressing these challenges involves:
Generating phospho-specific or other PTM-specific antibodies using synthetic peptides containing the modified residue
Employing enrichment strategies prior to detection (e.g., immunoprecipitation followed by Western blotting)
Validating specificity using both positive samples (modified protein) and negative controls (unmodified protein or dephosphorylated samples)
This multi-layered approach increases confidence in PTM detection while minimizing false positive results that can confound interpretation of regulatory mechanisms.
Epitope accessibility significantly impacts antibody performance across different experimental applications. For At4g13955 antibody applications, consider the following factors:
Native vs. denatured conditions: If the antibody was raised against a synthetic peptide derived from the human homolog of At4g13955 , it may perform differently in applications requiring native protein conformation versus those using denatured proteins.
Protein localization considerations: Membrane-associated proteins may have limited epitope accessibility in certain contexts, requiring specialized sample preparation techniques.
Protein-protein interactions: If At4g13955 forms complexes with other proteins, certain epitopes may be masked in vivo.
A methodological approach to addressing these challenges includes:
| Application | Epitope State | Recommended Approach |
|---|---|---|
| Western Blot | Denatured | SDS and reducing agents ensure epitope exposure |
| Co-IP | Native | Mild detergents preserve protein interactions |
| IHC/IF | Variable | Optimization of fixation and permeabilization |
Understanding these relationships allows researchers to select the appropriate experimental conditions based on antibody characteristics and target protein properties.
For low-abundance proteins like At4g13955 in certain plant tissues, several enrichment strategies can significantly improve detection sensitivity:
Subcellular fractionation: Isolating the cellular compartment where At4g13955 is predominantly localized concentrates the target protein relative to total cellular proteins.
Immunoprecipitation: Using the At4g13955 antibody to selectively capture the target protein from complex lysates before detection.
Recombinant expression systems: For certain applications, heterologous expression of tagged At4g13955 can provide a concentrated source of the protein for antibody validation and assay development.
The effectiveness of these approaches depends on antibody affinity, with higher-affinity antibodies (typically in the nanomolar range) allowing more efficient enrichment . When comparing enrichment methods, researchers should quantify both recovery efficiency and purity of the target protein to optimize experimental protocols.
Plant tissues present unique challenges for antibody applications due to their distinct biochemical composition. When working with At4g13955 antibodies in plant samples:
Address interfering compounds: Include polyvinylpyrrolidone (PVP) or polyvinylpolypyrrolidone (PVPP) in extraction buffers to sequester phenolic compounds that can interfere with antibody binding.
Optimize protein extraction: Use plant-specific extraction buffers containing appropriate detergents (e.g., CHAPS, Triton X-100) to solubilize membrane-associated proteins effectively.
Prevent proteolytic degradation: Add a comprehensive protease inhibitor cocktail specifically formulated for plant tissues, which often have distinct protease profiles compared to animal cells.
Consider tissue-specific modifications: Different plant tissues (leaves, roots, reproductive structures) may require distinct extraction protocols to effectively isolate proteins while minimizing background.
These modifications help ensure consistent and reliable results when applying antibody-based techniques to plant tissue samples.
When extending At4g13955 antibody applications beyond Arabidopsis to other plant species, systematic cross-reactivity testing is essential:
Sequence homology assessment: Begin with in silico analysis comparing the immunogen sequence used to generate the antibody with homologous proteins in target species. Higher sequence identity (>70%) suggests potential cross-reactivity.
Empirical validation approach:
| Validation Step | Method | Expected Outcome |
|---|---|---|
| Initial screening | Western blot with samples from multiple species | Detection of appropriately sized bands |
| Specificity confirmation | Immunoprecipitation followed by mass spectrometry | Identification of correct target protein |
| Functional validation | Immunolocalization compared to fluorescent protein fusions | Consistent subcellular localization patterns |
Control experiments: Include positive controls (Arabidopsis extracts) alongside experimental samples to verify antibody performance under identical conditions.
This systematic approach ensures reliable extension of antibody applications across different plant species while avoiding misinterpretation due to non-specific binding or detection of non-homologous proteins.
Batch-to-batch variability is a common challenge in antibody-based research. To address inconsistent At4g13955 antibody performance:
Implement standardized validation: For each new antibody lot, conduct validation experiments using consistent positive and negative controls.
Create internal reference standards: Maintain aliquots of well-characterized samples with known At4g13955 expression levels as benchmarks for new experiments.
Employ quantitative quality control measures:
| Quality Control Parameter | Acceptable Range | Troubleshooting Approach |
|---|---|---|
| Signal-to-noise ratio | >5:1 | Optimize blocking conditions |
| Positive control signal | Within 20% of reference value | Adjust antibody concentration |
| Negative control background | <10% of positive control signal | Increase washing stringency |
Document and track antibody performance: Maintain detailed records of antibody performance across experiments, including dilution factors, incubation conditions, and batch numbers.
This systematic approach allows researchers to identify potential sources of variability and implement appropriate corrective measures to ensure experimental reproducibility.
When conducting quantitative analyses with At4g13955 antibodies, appropriate normalization strategies are essential:
Loading control normalization: Use consistently expressed proteins (e.g., actin, tubulin, or GAPDH) as references, but verify that experimental conditions do not alter their expression.
Total protein normalization: Technologies such as stain-free gels or total protein stains (Ponceau S, Coomassie) offer advantages when loading controls might be affected by experimental conditions.
Spike-in controls: Adding defined amounts of recombinant proteins to samples provides an exogenous reference independent of biological variation.
Statistical approaches to normalization:
| Normalization Method | Advantages | Limitations |
|---|---|---|
| Housekeeping protein | Simple implementation | May vary under certain conditions |
| Total protein normalization | Independent of individual protein variations | Requires additional staining step |
| LICOR/Fluorescent dual detection | Simultaneous target and control detection | Requires specialized equipment |
The optimal normalization strategy depends on experimental design, expected changes in global protein expression, and available technical resources.
Discrepancies between protein and transcript levels of At4g13955 are common and can provide valuable biological insights:
Temporal considerations: Transcript changes typically precede protein changes, creating a time-dependent relationship that must be considered in experimental design.
Post-transcriptional regulation: miRNA regulation, alternative splicing, and differential translation efficiency can cause protein levels to diverge from transcript abundance.
Protein stability factors: Variations in protein half-life due to post-translational modifications or protein-protein interactions can significantly impact steady-state protein levels independent of transcript abundance.
Methodological approach to resolving discrepancies:
a. Time-course experiments to capture the relationship between transcript and protein dynamics
b. Analysis of protein degradation rates using cycloheximide chase or similar approaches
c. Investigation of post-translational modifications that might affect protein stability
d. Examination of translational efficiency through polysome profiling
Understanding the mechanistic basis of these discrepancies can reveal important regulatory layers controlling At4g13955 function in plant cells.