WDR77 Antibody

What is WDR77 and why is it important in cellular research?

WDR77, also known as MEP50, p44, or methylosome protein 50, is a non-catalytic component of the methylosome complex that includes PRMT5 and CLNS1A. This complex modifies specific arginines to dimethylarginines in several spliceosomal Sm proteins and histones . WDR77 is essential for targeting Sm proteins to the survival of motor neurons (SMN) complex for assembly into small nuclear ribonucleoprotein core particles. Additionally, it plays significant roles in transcription regulation and the methylation of Piwi proteins (PIWIL1, PIWIL2, and PIWIL4) . Recent research has identified WDR77 as a negative regulator of antiviral immune responses by inhibiting MAVS aggregation and as a contributor to cancer cell proliferation, particularly in squamous cell carcinoma .

What are the most effective applications for WDR77 antibodies in research?

WDR77 antibodies have demonstrated reliability across multiple experimental applications. Based on validated research, these antibodies are particularly effective for:

• Western blot (WB): Validated for detection in human cell lines (HEK-293, Jurkat cells) and rodent tissue lysates (mouse spleen, mouse kidney, rat kidney)

• Immunohistochemistry (IHC-P): Successfully used for human tissue sections, including breast cancer and testis tissue with recommended antigen retrieval methods using either TE buffer (pH 9.0) or citrate buffer (pH 6.0)

• Immunocytochemistry/Immunofluorescence (ICC/IF): Effective for cellular localization studies, particularly in HEK-293T cells

• Immunoprecipitation (IP): Useful for protein-protein interaction studies, especially when investigating WDR77 binding partners

• Flow cytometry: Validated for intracellular detection in fixed and permeabilized cells like HeLa cell lines

The selection of application should be guided by the specific research question and experimental design considerations.

What is the expected cellular localization pattern when using WDR77 antibodies?

When using WDR77 antibodies for immunofluorescence or immunohistochemistry, researchers should expect both nuclear and cytoplasmic localization patterns, with predominant nuclear staining in most cell types . In HEK-293T cells, WDR77 demonstrates distinct nuclear staining with some cytoplasmic distribution . During viral infection studies, researchers have observed that WDR77 can colocalize with MAVS, particularly after viral infection when their interaction is enhanced . When conducting immunofluorescence experiments, it is recommended to use appropriate subcellular markers (such as alpha-tubulin for cytoskeleton or nuclear stains like DAPI) to confirm the subcellular distribution patterns .

How can researchers optimize Western blot protocols for WDR77 detection?

For optimal Western blot detection of WDR77 (predicted molecular weight: 37 kDa), researchers should consider the following methodological approach:

• Sample preparation:

  • Use RIPA buffer containing protease inhibitors for cell lysis

  • Load 20-30 μg of total protein per lane for cell lysates

  • Include positive controls such as HEK-293 or Jurkat cell lysates

• Electrophoresis and transfer:

  • Use 10-12% SDS-PAGE gels for optimal separation

  • Transfer to PVDF or nitrocellulose membranes at 100V for 60-90 minutes

• Antibody dilution and incubation:

  • Primary antibody dilution: 1:1000-1:2000 for most commercial WDR77 antibodies

  • Incubate with primary antibody overnight at 4°C

  • Secondary antibody (HRP-conjugated): 1:5000-1:20000 dilution

• Detection considerations:

  • Due to the size similarity between WDR77 and common housekeeping proteins (e.g., GAPDH), select loading controls with distinct molecular weights

  • Enhanced chemiluminescence (ECL) systems are sufficient for detection with most WDR77 antibodies

When troubleshooting weak signals, consider extending primary antibody incubation time or using signal enhancement systems.

What are the critical considerations for successful WDR77 co-immunoprecipitation experiments?

For effective co-immunoprecipitation (co-IP) of WDR77 and its interacting partners:

• Buffer optimization:

  • Use mild lysis buffers containing 0.5-1% NP-40 or Triton X-100 to preserve protein-protein interactions

  • Include protease inhibitors and phosphatase inhibitors to prevent degradation

• Critical interaction partners to investigate:

  • PRMT5: Forms a stable complex with WDR77 in the methylosome

  • MAVS: WDR77 binds to MAVS proline-rich region through its WD2-WD3-WD4 domain

  • TRAF3: Co-immunoprecipitates with WDR77 (but not TRAF2, TRAF5, or TRAF6)

  • ΔNp63α: WDR77 and PRMT5 stabilize this protein in squamous cell carcinoma

• Experimental considerations:

  • Cross-linking may be beneficial for capturing transient or weak interactions

  • For viral infection studies, examine time-dependent interactions, as WDR77-MAVS interaction is augmented during early infection stages (0-16h) and declines later (16-32h)

  • Use appropriate negative controls (IgG or unrelated antibodies) to confirm specificity

• Detection methods:

  • Western blot analysis with specific antibodies against expected binding partners

  • For novel interaction partners, consider mass spectrometry analysis of immunoprecipitated complexes

How can researchers effectively use WDR77 antibodies in viral infection studies?

When investigating WDR77's role in viral infection and immune responses:

• Experimental design considerations:

  • Time course experiments are critical as WDR77-MAVS interaction changes over infection time (enhanced at 0-16h, declining at 16-32h)

  • Include appropriate virus controls (e.g., Sendai virus (SeV), vesicular stomatitis virus (VSV))

• Methodological approaches:

  • Semi-denaturing detergent agarose-gel electrophoresis (SDD-AGE) to monitor MAVS aggregation status with and without WDR77

  • Immunofluorescence to monitor WDR77-MAVS colocalization during infection

  • qPCR to measure induction of antiviral genes like IFNB1, ISG56, CXCL10

  • ELISA to quantify IFN-β production in cell culture supernatants

• Data analysis strategies:

  • Correlate MAVS aggregation with IFNB1 induction at different timepoints

  • Analyze phosphorylation status of downstream signaling components (TBK1, IRF3)

  • Compare virus replication efficiency between wild-type and WDR77-deficient cells

• Controls and validation:

  • Include MAVS-/- cells as negative controls for pathway specificity

  • Use WDR77 knockdown/knockout cells to confirm antibody specificity

How do WDR77 expression patterns correlate with cancer progression?

WDR77 demonstrates altered expression patterns across various cancer types that can be detected using specific antibodies:

• Expression correlation with clinical outcomes:

  • Overexpression of WDR77 correlates with poor survival in squamous cell carcinoma (SCC) patients

  • PRMT5/WDR77 complex appears essential for SCC cell line survival

• Tissue-specific considerations:

  • WDR77 shows positive immunohistochemical staining in human breast cancer tissue

  • Acts as a coactivator for both androgen and estrogen receptors, playing roles in hormonal effects during prostate and ovarian tumorigenesis

• Methodological approach for cancer tissue analysis:

  • IHC-P using WDR77 antibodies at 1:6000 dilution (0.05 μg/mL)

  • Heat-mediated antigen retrieval using epitope retrieval solution (pH 6.0)

  • Counterstaining with hematoxylin for contrast and nuclear visualization

  • Use of polymer detection systems with HRP/DAB for visualization

• Experimental controls:

  • Include matched normal tissues as expression baseline controls

  • Use PBS instead of primary antibody as negative control

What methodologies are most effective for studying WDR77-PRMT5 interactions in cancer contexts?

The WDR77-PRMT5 complex plays significant roles in cancer progression, requiring specific methodological approaches:

• Protein-protein interaction analysis:

  • Co-immunoprecipitation using either WDR77 or PRMT5 antibodies

  • Proximity ligation assays to visualize and quantify interactions in situ

  • Note that knockdown of either WDR77 or PRMT5 results in concurrent reduction of both proteins due to their mutual dependence

• Functional assessments:

  • Cell proliferation assays following WDR77 or PRMT5 depletion

  • Cell cycle analysis (WDR77/PRMT5 depletion induces G1 phase arrest in SCC)

  • Analysis of p21 expression, which is inhibited by the WDR77-PRMT5-ΔNp63α axis

• Genetic manipulation approaches:

  • CRISPR-Cas9 gene editing using appropriate sgRNAs (sequences available in literature)

  • For rescue experiments, use CRISPR-resistant WDR77 constructs with mutations based on codon frequency of the human genome

  • When knocking down WDR77, monitor PRMT5 levels as they are interdependent

• Expression system considerations:

  • Commercial cDNA constructs are available for wild-type WDR77 (e.g., MHS6278-202756033)

  • For domain-specific studies, create constructs focusing on the WD2-WD3-WD4 domain which is critical for MAVS interaction

How can researchers validate the specificity of WDR77 antibodies?

Ensuring antibody specificity is critical for accurate data interpretation. Recommended validation approaches include:

• Genetic controls:

  • Use WDR77 knockout or knockdown cells as negative controls

  • Multiple WDR77-deficient cell models have been described, including HEK293T, HEK293, HeLa, and mouse embryonic fibroblasts (MEFs)

• Multiple antibody validation:

  • Compare results using antibodies from different sources or clones

  • Assess concordance between monoclonal (e.g., EPR10708(B)) and polyclonal antibodies

• Application-specific controls:

  • For Western blot: Include lysates from multiple cell types with known WDR77 expression

  • For IHC/ICC: Perform peptide competition assays where available

  • For flow cytometry: Compare with isotype control antibodies

• Expected results:

  • Western blot should show a band at approximately 37 kDa

  • Immunofluorescence should reveal primarily nuclear localization with some cytoplasmic distribution

  • Flow cytometry should show intracellular staining distinct from isotype control

What are common artifacts or pitfalls when using WDR77 antibodies?

Researchers should be aware of these potential challenges:

• Cross-reactivity considerations:

  • WDR77 contains WD repeat domains that are structurally conserved across many proteins

  • Validate antibody specificity against other WD repeat-containing proteins

• Fixation-dependent artifacts:

  • For ICC/IF and IHC: 4% paraformaldehyde is recommended for fixation

  • Methanol fixation may alter epitope accessibility for some WDR77 antibodies

• Background issues in immunostaining:

  • Nonspecific nuclear staining can occur in some tissues

  • Use appropriate blocking (3-5% BSA or normal serum)

  • For flow cytometry, 90% methanol permeabilization has been validated for intracellular WDR77 detection

• Molecular weight considerations:

  • The predicted band size for WDR77 is 37 kDa

  • Post-translational modifications may result in higher molecular weight bands

  • WDR77 can form complexes with PRMT5 which may affect migration patterns

How can researchers investigate the role of WDR77 in regulating MAVS aggregation?

To study WDR77's inhibition of MAVS prion-like aggregation:

• Biochemical approaches:

  • Semi-denaturing detergent agarose-gel electrophoresis (SDD-AGE) to detect MAVS aggregation states

  • Analyze MAVS aggregation in a time-dependent manner (0-16h and 16-32h post-infection)

  • Express WDR77 in a dose-dependent manner to observe its impact on MAVS aggregation

• Structural considerations:

  • Focus on the WD2-WD3-WD4 domain of WDR77 that binds to MAVS proline-rich region

  • Generate domain-specific mutants to identify critical interaction residues

• Functional readouts:

  • Monitor IRF3 phosphorylation and dimerization as downstream indicators

  • Measure IFNB1 induction using qPCR and ELISA methods

  • Assess virus replication efficiency using plaque assays or fluorescent reporter viruses

• Advanced imaging techniques:

  • Super-resolution microscopy to visualize WDR77-MAVS interactions

  • Live-cell imaging to track dynamics of interaction during viral infection

What experimental models are most appropriate for studying WDR77 function in vivo?

For in vivo investigation of WDR77 functions:

• Mouse models:

  • Myeloid-specific Wdr77-deficient mice show enhanced resistance to RNA virus infection

  • Consider tissue-specific conditional knockout models when studying cancer-related roles

• Cellular models:

  • Multiple validated knockout cell lines exist: HEK293T, HEK293, HeLa cells, and MEFs

  • For cancer studies, SCC cell lines with WDR77 manipulation have been characterized

• Experimental design considerations:

  • For viral infection studies: use negative-strand RNA viruses (SeV, VSV) or poly(I:C) stimulation

  • For cancer studies: analyze cell cycle parameters and proliferation indices

  • Consider xenograft models to assess in vivo tumor growth dependencies

• Readout parameters:

  • Antiviral response genes: IFNB1, ISG56, CXCL10, ISG54, CCL5, IL6

  • Cancer-related pathways: p21 expression, cell cycle distribution

  • Survival analysis in infection models and tumor models