SPAC824.04 Antibody

Basic Research Questions

• What is SPAC824.04 and what are its basic characteristics?

  SPAC824.04 is an uncharacterized WD repeat-containing protein found in Schizosaccharomyces pombe (strain 972/ATCC 24843), commonly known as fission yeast. The protein is identified by UniProt accession number Q9UT39 . WD repeat-containing proteins typically function as platforms for protein-protein interactions and are involved in diverse cellular processes including signal transduction, transcription regulation, and cell cycle control.

  The protein has been observed to localize in both the cytoplasm and nucleus, suggesting potential roles in multiple cellular compartments. When designing experiments with this antibody, researchers should consider this dual localization for appropriate cellular fractionation techniques and immunostaining protocols.

• What experimental applications are suitable for SPAC824.04 antibody?

  Based on similar antibody products, SPAC824.04 antibody is suitable for several research applications:

  • Western blotting (WB)

  • Enzyme-linked immunosorbent assay (ELISA)

  • Immunohistochemistry (IHC)

  • Immunocytochemistry (ICC)

  • Immunoprecipitation (IP)

  When employing these techniques, researchers should optimize antibody concentration through titration experiments. For Western blotting, typically starting with dilutions of 1:500 to 1:2000 is recommended, while for immunofluorescence studies, starting with 1-10 μg/ml concentration is advisable. Always include appropriate positive and negative controls to validate antibody specificity .

• How should I store and handle SPAC824.04 antibody to maintain its activity?

  SPAC824.04 antibody preservation requires specific handling procedures:

  • Store at 2-8°C for short-term storage (up to 1 month)

  • For long-term storage, aliquot and store at -20°C to -80°C

  • Avoid repeated freeze-thaw cycles (limit to <5 cycles)

  • Protect conjugated antibodies from light exposure

  • Store in buffer formulations containing preservatives like sodium azide (≤0.1%)

  The antibody is typically shipped with ice packs and supplied in a buffer containing 50% Glycerol, 0.01M Phosphate Buffered Saline (PBS), pH 7.4, with 0.03% Proclin 300 as a preservative. This formulation helps maintain antibody stability during transport and storage.

• What is the difference between polyclonal and monoclonal versions of SPAC824.04 antibody?

  While specific information about available formats of SPAC824.04 antibody is limited in the search results, the general differences include:

  Polyclonal SPAC824.04 antibody:

  • Recognizes multiple epitopes on the SPAC824.04 protein

  • Typically produced in rabbits or other host species

  • Greater sensitivity due to binding multiple epitopes

  • Batch-to-batch variation might occur

  • Better for detecting denatured proteins in Western blot

  Monoclonal SPAC824.04 antibody:

  • Recognizes a single epitope on the SPAC824.04 protein

  • Produced from a single B-cell clone

  • Higher specificity for a particular epitope

  • Better consistency between batches

  • May be more suitable for applications requiring high specificity

  Researchers should select the appropriate antibody type based on their specific experimental requirements and validate accordingly .

Advanced Research Questions

• How can I validate the specificity of SPAC824.04 antibody in fission yeast studies?

  Validating SPAC824.04 antibody specificity is crucial for reliable research outcomes. A comprehensive validation approach includes:

  1. Knockout/knockdown controls: Using CRISPR-Cas9 or RNAi to create SPAC824.04-deficient yeast strains, then confirming absence of signal

  2. Overexpression validation: Comparing antibody signal between wild-type cells and those overexpressing SPAC824.04

  3. Peptide competition assay: Pre-incubating the antibody with excess purified SPAC824.04 protein or peptide should abolish specific signal

  4. Western blot analysis: Confirming a single band at the expected molecular weight

  5. Mass spectrometry validation: Following immunoprecipitation, confirm pulled-down protein identity via MS

  6. Cross-reactivity testing: Assess antibody specificity against closely related WD repeat proteins in fission yeast

  Documentation of these validation steps should be included in publications to ensure experimental reproducibility .

• What are optimal protocols for immunoprecipitation using SPAC824.04 antibody?

  For successful immunoprecipitation of SPAC824.04 from fission yeast, follow this optimized protocol:

  Cell Lysis and Extract Preparation:

  1. Grow S. pombe cells to mid-log phase (OD600 ~0.5-0.8)

  2. Harvest cells by centrifugation (3,000 × g, 5 min, 4°C)

  3. Wash with cold PBS

  4. Resuspend in IP lysis buffer (50 mM HEPES pH 7.5, 150 mM NaCl, 1 mM EDTA, 1% Triton X-100, 0.1% sodium deoxycholate)

  5. Add protease inhibitor cocktail

  6. Lyse cells using glass beads (10 cycles of 1 min vortex, 1 min on ice)

  7. Centrifuge lysate (16,000 × g, 15 min, 4°C)

  8. Collect supernatant for IP

  Immunoprecipitation:

  1. Pre-clear lysate with Protein A/G beads (1 hour, 4°C)

  2. Add 2-5 μg SPAC824.04 antibody per 500 μg protein lysate

  3. Incubate overnight at 4°C with gentle rotation

  4. Add 30 μl Protein A/G beads, incubate 2-3 hours at 4°C

  5. Wash beads 5× with IP wash buffer

  6. Elute with SDS sample buffer or low pH elution buffer

  For co-IP studies to identify protein interaction partners, use gentler lysis conditions (reduce detergent concentration to 0.5% Triton X-100) .

• How should I design experiments to study SPAC824.04 co-localization with other nuclear proteins?

  For effective co-localization studies of SPAC824.04 with other nuclear proteins, implement this experimental approach:

  Sample Preparation Protocol:

  1. Grow S. pombe cells to mid-log phase on appropriate media

  2. Fix cells with 3.7% formaldehyde for 30 minutes at room temperature

  3. Wash three times with PEM buffer (100 mM PIPES, 1 mM EGTA, 1 mM MgSO4, pH 6.9)

  4. Digest cell wall with Zymolyase (1 mg/ml in PEM with 1.2 M sorbitol) for 30 minutes at 37°C

  5. Permeabilize with 1% Triton X-100 for 5 minutes

  Immunostaining Protocol:

  1. Block with 5% BSA in PBS for 1 hour

  2. Co-incubate with SPAC824.04 antibody (1:100-1:500) and antibody against protein of interest

  3. Ensure antibodies are from different host species (e.g., rabbit anti-SPAC824.04 and mouse anti-protein X)

  4. Incubate overnight at 4°C in humidified chamber

  5. Wash 3× with PBS-T (0.1% Tween-20)

  6. Apply species-specific secondary antibodies with distinct fluorophores

  7. Counterstain nuclei with DAPI (1 μg/ml)

  8. Mount with anti-fade mounting medium

  Imaging Considerations:

  • Use confocal microscopy to minimize out-of-focus fluorescence

  • Apply spectral unmixing for closely emitting fluorophores

  • Perform sequential scanning to prevent bleed-through

  • Include controls for antibody specificity and non-specific binding

  • Quantify co-localization using Pearson's correlation coefficient or Manders' overlap coefficient .

• What controls are essential when using SPAC824.04 antibody for quantitative analyses?

  Rigorous controls are critical for quantitative analyses using SPAC824.04 antibody:

  Essential Controls Table:

  Control Type	Purpose	Implementation
  Isotype control	Assess non-specific binding	Use same host species IgG at identical concentration
  Secondary antibody only	Detect background signal	Omit primary antibody in control samples
  Positive control	Verify antibody functionality	Use samples with known SPAC824.04 expression
  Negative control	Confirm specificity	Use SPAC824.04 knockout/knockdown samples
  Loading control	Normalize protein levels	Probe for housekeeping proteins (e.g., GAPDH, actin)
  Peptide competition	Validate epitope specificity	Pre-incubate antibody with blocking peptide
  Titration control	Determine linear detection range	Use serial dilutions of protein extract
  Cross-reactivity control	Assess off-target binding	Test against related WD repeat proteins

  For flow cytometry applications, fluorescence-minus-one (FMO) controls should be included to set accurate gating boundaries.

  When performing quantitative Western blot, use a standard curve with recombinant protein to enable absolute quantification .

• How can SPAC824.04 antibody be used to investigate protein-protein interactions involving WD repeat domains?

  SPAC824.04 antibody can be utilized in multiple complementary approaches to study protein-protein interactions:

  Co-immunoprecipitation (Co-IP) Protocol:

  1. Perform IP as described in question 6

  2. Analyze co-precipitated proteins by mass spectrometry or Western blot

  3. Confirm interactions with reciprocal Co-IP using antibodies against interacting proteins

  4. Include detergent controls to distinguish direct vs. indirect interactions

  Proximity Ligation Assay (PLA) Protocol:

  1. Fix and permeabilize cells as for immunofluorescence

  2. Incubate with SPAC824.04 antibody and antibody against potential interaction partner

  3. Add PLA probes (secondary antibodies with oligonucleotide labels)

  4. Perform ligation and rolling circle amplification

  5. Visualize interaction sites as distinct fluorescent spots

  Bimolecular Fluorescence Complementation (BiFC):

  1. Generate constructs expressing SPAC824.04 fused to N-terminal fragment of fluorescent protein

  2. Fuse candidate interacting protein to C-terminal fragment

  3. Co-express in S. pombe

  4. Validate interaction specificity with SPAC824.04 antibody via immunostaining

  These techniques provide complementary data on protein interactions, with Co-IP identifying interaction partners, PLA showing spatial localization of interactions, and BiFC confirming direct interactions in living cells .

• What are the best practices for troubleshooting non-specific binding issues with SPAC824.04 antibody?

  When encountering non-specific binding with SPAC824.04 antibody, implement this systematic troubleshooting approach:

  Western Blot Non-Specificity Troubleshooting:

  1. Increase blocking stringency (5% BSA or 5% milk in TBST)

  2. Titrate primary antibody (test 1:500 to 1:5000 dilutions)

  3. Increase wash duration and frequency (5× 10-minute washes)

  4. Add 0.1-0.5% Tween-20 to antibody diluent

  5. Try different blocking agents (casein, commercial blockers)

  6. Optimize transfer conditions for WD repeat proteins

  7. Pre-adsorb antibody with yeast lysate lacking SPAC824.04

  Immunofluorescence Troubleshooting:

  1. Test different fixation methods (4% PFA, methanol, or acetone)

  2. Include 0.1% Triton X-100 in antibody diluent

  3. Use Image-iT® FX Signal Enhancer before blocking

  4. Increase blocking time to overnight at 4°C

  5. Test different antibody incubation temperatures

  Flow Cytometry Troubleshooting:

  1. Optimize permeabilization conditions

  2. Include Fc receptor blocking step

  3. Test different fixation protocols

  4. Use viability dye to exclude dead cells

  Document all optimization steps methodically to establish robust protocols for future experiments .

• How does fixation method affect SPAC824.04 epitope recognition in immunofluorescence experiments?

  Fixation methods significantly impact SPAC824.04 epitope preservation and accessibility:

  Comparative Analysis of Fixation Methods:

  Fixation Method	Mechanism	Effect on SPAC824.04 Detection	Recommended Protocol
  Paraformaldehyde (3-4%)	Cross-links proteins	Preserves morphology; may mask epitopes	15-20 min at room temperature
  Methanol	Precipitates proteins, removes lipids	Better for some nuclear proteins; may disrupt WD repeat structure	5-10 min at -20°C
  Acetone	Dehydrates and precipitates proteins	Rapid fixation; may extract some proteins	5 min at -20°C
  PFA followed by methanol	Combined cross-linking and precipitation	Improved nuclear protein detection	10 min PFA, then 5 min methanol
  Glyoxal	Alternative aldehyde fixative	May better preserve some protein structures	30 min at room temperature

  For optimal results with SPAC824.04 antibody in S. pombe, test multiple fixation methods in parallel. WD repeat proteins typically contain β-propeller structures that may be sensitive to fixation-induced conformational changes. After fixation optimization, gentle permeabilization with 0.1-0.2% Triton X-100 is typically recommended to maintain epitope integrity while allowing antibody access .

• What methodologies are most effective for quantifying SPAC824.04 expression levels across different cell cycle stages?

  To accurately quantify SPAC824.04 expression throughout the cell cycle, employ these methodologies:

  Synchronized Culture Protocol:

  1. Synchronize S. pombe using one of these methods:

     • Lactose gradient centrifugation

     • Nitrogen starvation and release

     • Hydroxyurea block and release

     • cdc25-22 temperature-sensitive mutant

  2. Collect samples at 15-20 minute intervals

  3. Split samples for parallel analyses:

  Flow Cytometry Analysis:

  1. Fix cells with 70% ethanol

  2. Permeabilize with 0.1% Triton X-100

  3. Stain with SPAC824.04 antibody (optimized concentration)

  4. Counterstain with propidium iodide for DNA content

  5. Perform dual-parameter analysis (SPAC824.04 vs. DNA content)

  Western Blot Quantification:

  1. Extract proteins using TCA precipitation method

  2. Normalize loading by cell number and verify with Coomassie staining

  3. Perform Western blot with SPAC824.04 antibody

  4. Include cyclin B (Cdc13) as cell cycle phase marker

  5. Quantify band intensity using densitometry

  Immunofluorescence Microscopy:

  1. Fix and permeabilize cells as optimized

  2. Stain with SPAC824.04 antibody

  3. Co-stain with SPB markers (Sad1) or septum (Calcofluor White)

  4. Classify cells by morphology and septation index

  5. Quantify nuclear/cytoplasmic SPAC824.04 signal intensity

  Integrated analysis of these complementary approaches provides robust quantification of SPAC824.04 expression dynamics throughout the cell cycle .