PRDM4 Antibody

What is PRDM4 and what are its primary biological functions?

PRDM4 is a highly conserved member of the PR/SET domain zinc finger protein family that functions as a transcription factor involved in cell differentiation and gene regulation. It contains a PR/SET domain and multiple zinc finger motifs that mediate DNA binding to a tripartite consensus sequence . PRDM4 plays critical roles in stem cell self-renewal and has demonstrated tumor suppressive functions in certain cancers, particularly by inhibiting cell proliferation through inactivation of the PI3K/AKT signaling pathway by directly transactivating PTEN expression . Additionally, PRDM4 functions as a transcription factor partner of YAP (Yes-associated protein), mediating YAP-induced cell invasion by activating leukocyte-specific integrin expression, notably ITGB2 .

Which types of PRDM4 antibodies are available for research applications?

Currently, researchers can access several validated antibody options for PRDM4 detection:

*The immunogen for the Novus Biologicals antibody corresponds to a custom peptide sequence: FCTSQDIPPENELLFYYSRDYAQQIGVPEHPDVHLCNCGKECNSYTEFKAHLTSHIHNHLPTQGHSGSHGPSHSKERKWKCSMC .

What is the standard approach for validating PRDM4 antibody specificity?

Antibody validation requires multiple complementary approaches. For PRDM4 antibodies, specificity has been validated through protein array screening against target protein plus 383 non-specific proteins , western blot analysis using recombinant PRDM4 protein fragments , and knockout/knockdown validation approaches. When initiating work with PRDM4 antibodies, researchers should include appropriate positive controls (cells known to express PRDM4, such as HeLa or HEK-293 cells) and negative controls (PRDM4 knockout or knockdown samples) . The inclusion of competing peptides or pre-adsorption controls can further confirm specificity, particularly for polyclonal antibodies.

What are the optimal conditions for Western blot detection of PRDM4?

For Western blot applications, the mouse monoclonal PRDM4 antibody (clone 4B6G1) has been validated at 1/500 dilution against both recombinant PRDM4 protein and endogenous PRDM4 in HEK-293 cell lysates . The predicted molecular weight of PRDM4 is approximately 88 kDa. For optimal results:

• Use RIPA or NP-40 based lysis buffers supplemented with protease inhibitors

• Load 20-40 μg of total protein per lane

• Transfer to PVDF membrane (recommended over nitrocellulose for this protein)

• Block with 5% non-fat milk in TBST (1 hour at room temperature)

• Incubate with primary antibody at 1/500 dilution overnight at 4°C

• Wash 3x with TBST

• Incubate with appropriate HRP-conjugated secondary antibody (1/2000-1/5000)

• Develop using enhanced chemiluminescence (ECL) technique

Careful sample preparation is critical as PRDM4 is susceptible to degradation during extended processing times.

How should researchers optimize immunocytochemistry protocols for PRDM4 detection?

For immunocytochemistry/immunofluorescence applications, the rabbit polyclonal PRDM4 antibody has been validated at 1-4 μg/mL concentration . The following protocol is recommended:

• Fix cells in 4% paraformaldehyde (10 minutes at room temperature)

• Permeabilize with 0.1% Triton X-100 in PBS (5 minutes)

• Block with 1% BSA, 10% normal goat serum in PBS (1 hour)

• Incubate with primary antibody at 1-4 μg/mL in blocking solution (overnight at 4°C)

• Wash 3x with PBS

• Incubate with fluorophore-conjugated secondary antibody (1 hour at room temperature)

• Counterstain nuclei with DAPI

• Mount and image

PRDM4 typically shows both nuclear and cytoplasmic localization, with enrichment in the nucleus consistent with its role as a transcription factor. Dual staining with nuclear markers helps confirm proper subcellular localization patterns.

What approaches are recommended for studying PRDM4 DNA binding activity?

To investigate PRDM4 DNA binding activity, researchers have used several complementary techniques:

• SELEX (Systematic Evolution of Ligands by Exponential Enrichment):

  • Express recombinant PRDM4 zinc finger domain in bacteria using pET28a expression system

  • Induce with 0.1 mM IPTG

  • Purify recombinant protein

  • Perform SELEX as described by standard protocols to identify DNA binding motifs

• ChIP-seq (Chromatin Immunoprecipitation followed by Sequencing):

  • Crosslink protein-DNA complexes in living cells

  • Immunoprecipitate with PRDM4 antibody

  • Sequence and analyze bound DNA fragments

• Luciferase Reporter Assays:

  • Generate reporter constructs containing putative PRDM4 binding sites

  • Co-transfect with PRDM4 expression vectors

  • Measure luciferase activity to quantify transcriptional regulation

These approaches have revealed that PRDM4 DNA binding is exclusively mediated by its zinc finger domain, recognizing a tripartite consensus sequence .

How can researchers effectively study PRDM4's role in cancer biology?

PRDM4 has demonstrated tumor suppressive functions in cervical cancer through PTEN transactivation and PI3K/AKT pathway inhibition . To investigate PRDM4's role in cancer:

• Expression Analysis:

  • Compare PRDM4 expression levels between normal and tumor tissues using immunohistochemistry and western blot

  • Correlate expression with clinicopathological parameters and patient outcomes

• Functional Studies:

  • Generate stable PRDM4 overexpression and knockdown cell lines

  • Assess effects on:

    • Cell proliferation (MTT/CCK-8 assays)

    • Cell cycle progression (flow cytometry with PI staining)

    • Migration and invasion (transwell assays)

    • Tumorigenic potential (xenograft models)

• Molecular Mechanism Investigation:

  • Examine effects on PI3K/AKT pathway components (p-AKT, PTEN)

  • Analyze cell cycle regulators (p27, p21, Cyclin D1, CDK4)

  • Perform rescue experiments using PTEN silencing or inhibitors to confirm pathway involvement

In cervical cancer models, PRDM4 overexpression induces cell cycle arrest at G0/G1 to S phase transition, upregulates p27 and p21, and downregulates Cyclin D1 and CDK4, ultimately inhibiting cell proliferation and tumorigenesis .

What approaches should be used to study PRDM4-YAP interactions in cellular invasion?

PRDM4 has been identified as a novel YAP WW domain-interacting transcription factor that mediates YAP-induced cell invasion . To investigate this interaction:

• Protein-Protein Interaction Analysis:

  • Co-immunoprecipitation using PRDM4 or YAP antibodies

  • Proximity ligation assays to visualize interactions in situ

  • Mutation of PRDM4 PPXY motifs to confirm interaction specificity

• Transcriptional Cooperation:

  • Luciferase reporter assays using ITGB2 promoter constructs

  • ChIP-qPCR to examine co-occupancy at target gene promoters

  • Analysis of target gene expression with individual or combined knockdown of PRDM4 and TEAD factors

• Functional Characterization:

  • Transendothelial migration assays

  • Xenograft tumor formation assays with PRDM4 knockout or wildtype cells expressing active YAP

Research has demonstrated that both PRDM4 and TEAD factors are required for full YAP-mediated ITGB2 induction, and PRDM4 knockout inhibits YAP-induced cell invasion and tumorigenesis .

What considerations should researchers take when studying PRDM4 gene targeting and knockout models?

Several strategies have been employed to generate PRDM4 knockout or modified models:

• Zinc Finger Domain Deletion (ΔZF):

  • Target the zinc finger domain using homologous recombination

  • Employ loxP-flanked selection cassettes for conditional deletion

  • Confirm targeting by Southern blotting

• Complete Gene Targeting:

  • EUCOMM targeting vectors (e.g., project ID 45696)

  • Selection with G418 (200 μg/ml)

  • Screening by Southern blotting

  • Conversion to null allele using Cre recombinase (e.g., Sox2.Cre)

• CRISPR-Cas9 Genome Editing:

  • Design gRNAs targeting critical exons

  • Confirm knockout by genomic DNA sequencing

  • Validate at protein level by western blotting

When analyzing PRDM4 knockout models, researchers should consider potential compensatory mechanisms involving other PRDM family members and examine phenotypes in multiple cellular contexts, as PRDM4 functions may be cell-type dependent.

What are common issues encountered when using PRDM4 antibodies and how can they be resolved?

Researchers may encounter several challenges when working with PRDM4 antibodies:

For flow cytometry applications, permeabilization is critical as PRDM4 has both nuclear and cytoplasmic localization. Fixation with 4% paraformaldehyde followed by permeabilization with 0.1% saponin or 0.3% Triton X-100 typically yields optimal results .

How can researchers differentiate between PRDM4 and other PRDM family members?

The PRDM family consists of 17 members sharing structural similarities, which can pose specificity challenges. To ensure PRDM4-specific detection:

• Antibody Selection:

  • Choose antibodies raised against unique regions of PRDM4 not conserved in other family members

  • The mouse monoclonal antibody (clone 4B6G1) targets aa 450-600, a region with limited homology to other PRDM proteins

• Validation Controls:

  • Include PRDM4 knockout or knockdown samples as negative controls

  • Perform peptide competition assays with the specific immunogen

  • Consider western blot analysis with recombinant proteins of multiple PRDM family members

• Expression Analysis Verification:

  • Confirm antibody results with orthogonal methods (e.g., qRT-PCR for PRDM4 mRNA)

  • Use multiple antibodies targeting different epitopes

  • Employ immunoprecipitation followed by mass spectrometry to confirm detection of PRDM4-specific peptides

These approaches collectively enhance confidence in the specificity of PRDM4 detection.

What emerging applications of PRDM4 antibodies show promise for advancing understanding of disease mechanisms?

Recent discoveries about PRDM4's roles in signaling pathways and cancer biology open several promising research directions:

• Cancer Biomarker Development:

  • Evaluation of PRDM4 expression patterns across cancer types beyond cervical cancer

  • Correlation with treatment response and patient outcomes

  • Potential as a diagnostic or prognostic marker

• Therapeutic Target Identification:

  • Screening for compounds that modulate PRDM4 expression or activity

  • Examination of PRDM4 restoration as a strategy in cancers with downregulated expression

  • Investigation of synthetic lethality approaches in PRDM4-deficient tumors

• Signaling Pathway Integration:

  • Comprehensive mapping of PRDM4 interactions with YAP/Hippo pathway components

  • Exploration of PRDM4 involvement in additional signaling networks

  • Identification of context-dependent PRDM4 functions across tissue types

• Chromatin Regulation Mechanisms:

  • Genome-wide profiling of PRDM4 chromatin occupancy

  • Analysis of PRDM4's role in chromatin modification and epigenetic regulation

  • Characterization of PRDM4 interactions with chromatin remodeling complexes

The development of more specific and sensitive PRDM4 antibodies suitable for these applications will be crucial for advancing our understanding of PRDM4 biology and its implications in disease.

How can existing PRDM4 antibodies be leveraged for studying novel transcriptional regulatory mechanisms?

PRDM4 antibodies enable investigation of several emerging aspects of transcriptional regulation:

• Co-factor Identification:

  • Immunoprecipitation coupled with mass spectrometry to identify novel PRDM4-interacting proteins

  • ChIP-seq analyses to map genomic co-occupancy with established transcription factors

  • Sequential ChIP (re-ChIP) to identify complexes containing PRDM4 and partner proteins

• Target Gene Regulation:

  • Integration of ChIP-seq and RNA-seq data to comprehensively map PRDM4-regulated gene networks

  • Analysis of PRDM4 binding motifs and co-occurring transcription factor binding sites

  • Investigation of context-dependent PRDM4 target regulation across cell types

• Post-translational Modifications:

  • Identification of PRDM4 modifications (phosphorylation, ubiquitination, etc.)

  • Analysis of how these modifications affect PRDM4 function, localization, and stability

  • Mapping of signaling pathways that regulate PRDM4 activity through post-translational mechanisms

• Single-cell Applications:

  • Adaptation of PRDM4 antibodies for single-cell protein analysis techniques

  • Integration with transcriptomic data to examine cellular heterogeneity in PRDM4 function

  • Spatial analysis of PRDM4 expression and activity in tissue contexts

These approaches will help elucidate PRDM4's role in complex transcriptional regulatory networks and potentially identify novel therapeutic opportunities.