PWWP2B Antibody

What is PWWP2B and why is it significant in research?

PWWP2B (PWWP Domain Containing 2B) is a nuclear protein that plays a critical role in DNA double-strand break (DSB) repair. Research has identified PWWP2B as one of the most frequently mutated genes in Korean gastric adenocarcinoma patients, with mutations correlating significantly with lower cancer patient survival . The protein contains a PWWP domain and functions in homologous recombination (HR)-mediated DNA repair.

What are the primary applications of PWWP2B antibodies in research?

PWWP2B antibodies serve multiple critical research applications:

• Western Blotting (WB): All commercially available PWWP2B antibodies are validated for western blotting applications, typically used at dilutions ranging from 1:500 to 1:3000 . This application allows researchers to detect and quantify PWWP2B protein expression in cell or tissue lysates.

• Immunofluorescence/Immunocytochemistry (IF/ICC): Several antibodies are validated for IF/ICC applications at dilutions of approximately 1:100 to 1:500 . This technique enables visualization of PWWP2B localization within cells, particularly important for studying its recruitment to DNA damage sites.

• Enzyme-Linked Immunosorbent Assay (ELISA): Some antibodies are suitable for ELISA applications at dilutions up to 1:20000 , allowing for quantitative measurement of PWWP2B in solution.

• DNA Damage Response Studies: PWWP2B antibodies can be used to monitor the protein's translocation to DNA lesion sites following DNA damage, as demonstrated by laser microirradiation studies .

• Protein-Protein Interaction Analysis: Antibodies enable the study of PWWP2B interactions with other proteins, such as UHRF1, MRE11, and DNA repair factors through co-immunoprecipitation experiments .

How should researchers select the appropriate PWWP2B antibody for their experiments?

Selection of an appropriate PWWP2B antibody requires consideration of several factors:

• Target Epitope: Different antibodies target different regions of PWWP2B, including N-terminal , internal regions , and specific amino acid sequences (e.g., AA 35-84, AA 268-317) . The epitope choice should align with your research question—for example, if studying domain-specific functions, select antibodies that target or avoid that specific domain.

• Species Reactivity: Verify that the antibody reacts with your species of interest. While most PWWP2B antibodies react with human samples, some also recognize mouse, rat, cow, and pig PWWP2B . For instance, one antibody shows predicted reactivity of 100% for human and cow, 92% for mouse, and 93% for rat PWWP2B .

• Application Compatibility: Ensure the antibody is validated for your intended application (WB, IF/ICC, ELISA). For example, while most antibodies work for western blotting, fewer are validated for immunofluorescence applications .

• Clonality: All commercially available PWWP2B antibodies appear to be polyclonal and rabbit-derived . Polyclonal antibodies typically offer higher sensitivity but potentially lower specificity than monoclonals.

• Validation Data: Request validation data for your specific application and cell/tissue type if available.

What are the recommended storage and handling protocols for PWWP2B antibodies?

Proper storage and handling of PWWP2B antibodies are essential for maintaining antibody integrity and experimental reproducibility:

• Storage Temperature: Store PWWP2B antibodies at -20°C for long-term preservation . This temperature prevents degradation while maintaining antibody function.

• Buffer Composition: Most commercial PWWP2B antibodies are supplied in phosphate-buffered saline (PBS, pH 7.4) containing 150mM NaCl, with either 0.02% sodium azide and 50% glycerol or similar stabilizing components.

• Aliquoting: To prevent freeze-thaw cycles that can degrade antibody quality, aliquot the stock solution upon receipt into smaller volumes based on anticipated usage .

• Freeze-Thaw Cycles: Minimize repeated freeze-thaw cycles as specified in product documentation. The recommendation to "avoid repeated freeze/thaw cycles" appears in multiple product descriptions .

• Working Dilution Preparation: When preparing working dilutions, use fresh, cold buffer and keep the antibody on ice during handling.

• Stability: Properly stored antibodies remain stable for approximately 12 months from receipt .

How can PWWP2B antibodies be used to study DNA damage repair mechanisms?

PWWP2B antibodies provide powerful tools for investigating DNA damage repair mechanisms through several methodological approaches:

• Laser Microirradiation Combined with Immunofluorescence:

  • Apply laser microirradiation to induce localized DNA damage in cellular models

  • Fix cells at different timepoints (1-20 minutes post-irradiation)

  • Use PWWP2B antibodies for immunofluorescence to visualize and quantify recruitment kinetics

  • Research has shown that endogenous PWWP2B accumulates at laser-induced DNA lesions within 1 minute, with peak accumulation at 3 minutes

• Co-localization Studies with DNA Repair Proteins:

  • Use dual immunofluorescence with PWWP2B antibodies and antibodies against other DNA repair proteins (UHRF1, MRE11, RAD51)

  • Quantify co-localization at DNA damage sites to establish functional relationships

  • The kinetics data shows PWWP2B and UHRF1 have similar recruitment patterns, suggesting coordinated function

• PWWP2B Depletion Impact Analysis:

  • Use PWWP2B antibodies to confirm knockdown efficiency in siRNA or CRISPR-Cas9 experiments

  • Monitor formation of IR-induced foci of downstream repair proteins (BRCA1, RPA2, RAD51)

  • Research has demonstrated that PWWP2B depletion impairs foci formation of these proteins, indicating its role in DNA end resection

• Protein-Protein Interaction Mapping:

  • Utilize PWWP2B antibodies for co-immunoprecipitation experiments followed by western blotting

  • This approach has revealed interactions with UHRF1 and MRE11, key players in DNA repair

  • Both endogenous and overexpressed PWWP2B interactions can be studied with appropriate antibody selection

What experimental designs are optimal for studying PWWP2B's role in gastric cancer using antibody-based approaches?

Research into PWWP2B's role in gastric cancer requires carefully designed experimental approaches leveraging antibody-based methods:

How can researchers validate the specificity of PWWP2B antibodies in their experimental systems?

Validating antibody specificity is crucial for ensuring reliable experimental results. For PWWP2B antibodies, consider these methodological approaches:

• Genetic Knockdown/Knockout Controls:

  • Generate PWWP2B-depleted cells using siRNA, shRNA, or CRISPR-Cas9

  • Perform western blotting with the PWWP2B antibody

  • A specific antibody should show significantly reduced or absent signal in knockdown/knockout samples compared to controls

  • This approach provides the most definitive validation of antibody specificity

• Peptide Competition Assay:

  • Pre-incubate the PWWP2B antibody with excess immunizing peptide (if available from manufacturer)

  • Perform western blotting or immunofluorescence in parallel with untreated antibody

  • Specific binding should be blocked by the peptide, resulting in signal reduction or elimination

• Overexpression Validation:

  • Transfect cells with tagged PWWP2B (e.g., SFB-PWWP2B or GFP-PWWP2B as used in the research )

  • Perform western blotting or immunofluorescence using both tag-specific and PWWP2B antibodies

  • Signals should overlap, confirming antibody specificity

• Molecular Weight Verification:

  • PWWP2B has a calculated molecular weight of approximately 64 kDa

  • Verify that the detected band appears at the expected size in western blots

  • Consider posttranslational modifications that might alter apparent molecular weight

• Cross-Species Reactivity Testing:

  • If working with non-human samples, validate antibody performance in your species

  • Compare signal patterns between human and target species samples

  • Consider sequence homology predictions (e.g., mouse PWWP2B shows 92% predicted reactivity with some antibodies )

What are the optimal protocols for using PWWP2B antibodies to study its interaction with UHRF1?

Studying the PWWP2B-UHRF1 interaction requires carefully optimized protocols:

• Co-immunoprecipitation (Co-IP) Protocol:

  • Lyse cells in a mild detergent buffer to preserve protein-protein interactions

  • Incubate lysate with PWWP2B antibody (or UHRF1 antibody for reverse co-IP)

  • Capture antibody-protein complexes using Protein A/G beads

  • Wash thoroughly to remove non-specific interactions

  • Elute bound proteins and analyze by western blotting

  • Research has validated this approach for both endogenous and overexpressed proteins

• Proximity Ligation Assay (PLA):

  • Fix cells on coverslips and permeabilize

  • Incubate with primary antibodies against PWWP2B and UHRF1 from different host species

  • Apply species-specific PLA probes and perform ligation and amplification

  • Visualize interaction signals by fluorescence microscopy

  • This technique allows visualization of endogenous protein interactions in situ

• Domain Mapping Studies:

  • Generate PWWP2B deletion constructs as described in the research (D1-D5)

  • Express these constructs in appropriate cell models

  • Perform co-IP with UHRF1

  • Use western blotting to identify which domains are required for interaction

  • Research has identified amino acids 130-317 of PWWP2B as critical for UHRF1 binding

• DNA Damage-Induced Interaction Dynamics:

  • Treat cells with DNA-damaging agents (e.g., ionizing radiation)

  • Harvest cells at different timepoints post-treatment

  • Perform co-IP and western blotting to assess temporal changes in PWWP2B-UHRF1 interaction

  • Correlate with recruitment to DNA damage sites

What methodological approaches can be used to investigate PWWP2B's role in DNA end resection?

DNA end resection is a critical step in homologous recombination repair, and PWWP2B has been implicated in this process. The following methodological approaches can be employed:

• RPA/RAD51 Foci Formation Assay:

  • Generate PWWP2B-depleted cells alongside controls

  • Induce DNA damage using ionizing radiation

  • Fix cells at appropriate timepoints

  • Perform immunofluorescence for RPA2 and RAD51

  • Quantify foci formation as a readout of end resection efficiency

  • Research has shown that PWWP2B depletion severely impairs IR-induced BRCA1, RPA2, and RAD51 foci formation

• BrdU Resection Assay:

  • Grow cells with BrdU to label DNA

  • Induce DNA damage

  • Extract DNA under non-denaturing conditions

  • Detect exposed BrdU (single-stranded DNA) using anti-BrdU antibodies

  • Compare between PWWP2B-proficient and PWWP2B-depleted cells

• MRE11 Nuclease Activity Assessment:

  • PWWP2B interacts with MRE11, a key nuclease in end resection

  • Develop in vitro nuclease assays using purified proteins

  • Compare MRE11 activity in the presence or absence of PWWP2B

  • Use PWWP2B antibodies to confirm protein levels in your experimental system

• ChIP-Sequencing at DNA Break Sites:

  • Induce site-specific DNA breaks using CRISPR-Cas9 or restriction enzymes

  • Perform ChIP using PWWP2B antibodies

  • Sequence immunoprecipitated DNA to map PWWP2B binding sites

  • Compare with ChIP-seq data for known end resection factors

• Real-time Recruitment Kinetics:

  • Use live-cell imaging with fluorescently tagged proteins

  • Apply laser microirradiation to induce localized DNA damage

  • Monitor recruitment of PWWP2B alongside end resection markers

  • Quantify recruitment kinetics as demonstrated in previous research showing PWWP2B recruitment peaking at 3 minutes post-damage

What are the emerging research questions about PWWP2B that antibody-based approaches could help address?

Several critical research questions about PWWP2B remain unanswered and could be addressed using antibody-based approaches:

• Tissue-Specific Expression Patterns:

  • How does PWWP2B expression vary across normal and diseased tissues beyond gastric cancer?

  • Antibody-based tissue microarray analysis could map expression across diverse tissue types

• Post-Translational Modifications:

  • What post-translational modifications regulate PWWP2B function in DNA repair?

  • Phospho-specific or other modification-specific antibodies could be developed

• Chromatin Association Mechanisms:

  • How does PWWP2B associate with chromatin beyond DNA damage sites?

  • ChIP-seq approaches using PWWP2B antibodies could map genomic binding sites

• Cancer Type Specificity:

  • Is PWWP2B's role in DNA repair and cancer progression consistent across different cancer types?

  • Immunohistochemistry panels across cancer tissue arrays could address this question

• Therapeutic Targeting Potential:

  • Could targeting the PWWP2B-UHRF1 interaction have therapeutic value in cancer treatment?

  • Antibody-based screening assays could identify interaction inhibitors

• Biomarker Development:

  • Can PWWP2B expression or localization patterns serve as biomarkers for DNA repair deficiencies?

  • Standardized immunohistochemistry protocols would be needed for clinical application