ZNF703 Antibody

What is ZNF703 and why is it significant in cancer research?

ZNF703 is a zinc finger protein that functions as a transcriptional co-factor in a nuclear complex comprising DCAF7, PHB2, and NCOR2 . Its significance stems from its amplification and overexpression in Luminal B breast cancers, where it acts as an oncogene associated with poor clinical outcomes. High levels of ZNF703 mRNA correlate with decreased disease-free survival (5-year DFS of 68% versus 78% for low ZNF703 expression) . ZNF703 plays prominent roles in transcription modulation, stem cell regulation, and luminal B oncogenesis, making it a critical target for breast cancer research .

What are the optimal applications for polyclonal versus monoclonal ZNF703 antibodies?

Polyclonal antibodies like the rabbit-derived HPA023930 are particularly valuable for immunohistochemistry applications as they recognize multiple epitopes, potentially enhancing detection sensitivity in fixed tissues . These antibodies have been extensively validated through the Human Protein Atlas project, with testing against hundreds of normal and disease tissues . For applications requiring higher specificity and reduced batch-to-batch variation, monoclonal antibodies would be preferable, though the search results don't specifically mention monoclonal options for ZNF703. The selection should be guided by experimental goals: use polyclonal antibodies for initial detection and localization studies, and consider monoclonal antibodies for quantitative analyses or when cross-reactivity is a concern.

What subcellular localization pattern should researchers expect when using ZNF703 antibodies?

ZNF703 displays a distinctive nuclear localization pattern characterized by dot-like nuclear structures. Immunofluorescence studies have demonstrated that ZNF703 co-localizes with interacting partners DCAF7 and PHB2 within these nuclear dots . Interestingly, while ZNF703 interacts with HSP60 as confirmed by co-immunoprecipitation experiments, these proteins do not co-localize in the nuclear matrix . When performing immunofluorescence with ZNF703 antibodies, researchers should expect to observe this punctate nuclear pattern rather than diffuse nuclear staining, particularly in breast cancer cell lines that express the protein at detectable levels.

How should researchers optimize immunohistochemistry protocols for ZNF703 detection?

For optimal ZNF703 detection using immunohistochemistry, researchers should follow these methodological guidelines:

• Antibody dilution: Use the HPA023930 ZNF703 antibody at a dilution range of 1:20-1:50 for immunohistochemistry applications .

• Antigen retrieval: Implement heat-induced epitope retrieval (precise conditions not specified in the search results but typically citrate buffer pH 6.0 or EDTA buffer pH 9.0).

• Validation: Include positive controls such as luminal B breast cancer tissues known to overexpress ZNF703 .

• Negative controls: Include antibody diluent-only controls and tissues known to have low ZNF703 expression.

• Counterstaining: Use hematoxylin for nuclear visualization to properly contextualize the nuclear localization of ZNF703.

The Human Protein Atlas project provides extensive validation data for the HPA023930 antibody, which researchers can reference when establishing their protocols .

What experimental approaches can validate ZNF703 antibody specificity?

Validating ZNF703 antibody specificity requires a multi-faceted approach:

• RNA interference validation: Compare antibody detection in cells with normal ZNF703 expression versus cells with ZNF703 knockdown (as performed in MCF7 and HCC1500 cells) . Western blotting should show reduced signal intensity following successful knockdown.

• Overexpression validation: Compare detection in control cells versus cells overexpressing ZNF703 (via lentiviral transduction) . Increased signal intensity confirms antibody specificity.

• Protein array screening: The HPA023930 antibody has been validated against a protein array of 364 human recombinant protein fragments to ensure low cross-reactivity .

• Immunoprecipitation followed by mass spectrometry: This approach can confirm that the antibody pulls down the correct protein target, as demonstrated in studies that identified ZNF703-interacting proteins .

• Correlation with genomic amplification: Compare antibody detection in cell lines with and without 8p12 amplification (the genomic region containing ZNF703) .

What considerations should be made when designing ChIP experiments using ZNF703 antibodies?

When designing Chromatin Immunoprecipitation (ChIP) experiments with ZNF703 antibodies, researchers should consider:

• Target selection: Based on existing data, design primers against promoter regions of candidate target genes like TGFBR2, focusing on regions with H3K4me1 or H3K4me3 histone modifications (as identified from public Encode datasets) .

• Controls: Include:

  • Negative control regions (like the PRKCE gene) that are not regulated by ZNF703

  • Input chromatin controls

  • IgG isotype controls to assess non-specific binding

• Co-factors assessment: Consider ChIP for ZNF703-associated factors like HDAC1 and p300 to determine repressive versus active transcriptional states at target regions .

• Validation approach: Combine ChIP with ZNF703 manipulation (knockdown/overexpression) to observe changes in co-factor recruitment and target gene expression, as demonstrated for TGFBR2 .

• Fixation conditions: Optimize formaldehyde fixation time (typically 10-15 minutes) to effectively capture ZNF703 interactions with chromatin while maintaining DNA integrity.

How can researchers reliably quantify ZNF703 amplification and overexpression?

Researchers can employ several complementary approaches to quantify ZNF703 amplification and overexpression:

For the most robust analysis, researchers should combine at least two methods, ideally at different levels (DNA, RNA, protein). Studies have demonstrated correlation between genomic amplification at 8p12 and increased gene and protein expression, particularly in Luminal B breast cancers .

What are the known molecular interactions of ZNF703 and how can they be studied?

ZNF703 forms a nuclear complex with several key proteins that contribute to its function in transcriptional regulation:

• Identified interactions: Mass spectrometry and co-immunoprecipitation studies have confirmed ZNF703 interactions with:

  • DCAF7 (nuclear co-localization in dot-like structures)

  • PHB2 (Prohibitin 2, nuclear co-localization)

  • HSP60 (interaction confirmed but no nuclear co-localization)

  • NCOR2 (part of the nuclear complex)

• Methodological approaches:

  • Co-immunoprecipitation followed by Western blotting for targeted validation

  • Mass spectrometry for unbiased identification of interacting partners

  • Immunofluorescence co-localization studies

  • Proximity ligation assays for in situ interaction confirmation

• Functional relevance: These interactions suggest ZNF703 participates in transcriptional repression, as PHB2 and NCOR2 are known transcriptional co-repressors. This is further supported by ChIP experiments showing HDAC1 recruitment to ZNF703-bound regions .

How does ZNF703 expression correlate with clinical outcomes in breast cancer subtypes?

ZNF703 expression shows significant clinical correlations in breast cancer:

• Subtype specificity: ZNF703 overexpression is predominantly associated with Luminal B breast cancers compared to Luminal A (p = 4 × 10⁻⁶) or other subtypes (p = 1.2 × 10⁻⁵³) .

• Prognostic value: High ZNF703 mRNA levels correlate with decreased disease-free survival in luminal tumors:

  • 5-year DFS of 68% for high ZNF703 expression

  • 5-year DFS of 78% for low ZNF703 expression

  • Statistically significant difference (p = 0.0136)

• Molecular correlations: In tumors with ZNF703 amplification/overexpression, several genes show consistent expression changes:

  • Upregulated: DHRS2, HPGD, ID2, IRX5, SLOM1, NLK, EFHD1

  • Downregulated: ZFP36L2, UGT2B7, RALB, TGFBR2

These findings suggest ZNF703 status could serve as both a prognostic biomarker and potential therapeutic target specifically in Luminal B breast cancers.

How can ZNF703 antibodies be used to investigate stem cell-related functions?

ZNF703 has been implicated in stem cell regulation, making antibody-based detection crucial for this research area:

• Tumoursphere assays: ZNF703 overexpression increases primary and secondary tumoursphere formation, particularly in the presence of estrogen (E2) . Researchers can use ZNF703 antibodies to:

  • Compare protein levels in adherent versus sphere cultures

  • Assess subcellular localization changes in cancer stem cells (CSCs)

  • Perform immunofluorescence on sections of tumourspheres

• Colony formation assays: ZNF703 overexpression enhances colony formation from luminal progenitors . Researchers can:

  • Use immunostaining to track ZNF703 expression during colony development

  • Correlate protein levels with colony morphology and size

• Pathway analysis: Gene expression studies revealed ZNF703 overexpression activates stem cell-related gene networks . Researchers can employ ChIP with ZNF703 antibodies to:

  • Identify direct binding to stem cell-related gene promoters

  • Map the epigenetic landscape at these loci (in combination with histone modification ChIP)

• Co-staining approaches: Combine ZNF703 antibodies with established stem cell markers to:

  • Profile ZNF703 expression in different stem/progenitor subpopulations

  • Track changes in ZNF703-positive cells during differentiation

What methodological considerations are important when studying ZNF703 in relation to TGFβ signaling?

When investigating ZNF703's relationship with TGFβ signaling, researchers should consider:

• Experimental design for proliferation studies:

  • Measure BrdU incorporation in cells with manipulated ZNF703 expression (knockdown/overexpression)

  • Include conditions with and without TGFβ treatment

  • Control for cell cycle phase distribution using EdU incorporation and flow cytometry

• Gene expression analysis:

  • Monitor TGFBR2 expression changes upon ZNF703 manipulation (RT-qPCR validation is critical)

  • Apply pathway analysis to identify other TGFβ pathway members affected

  • Use time-course experiments to distinguish direct versus indirect effects

• ChIP methodology for mechanism studies:

  • Design primers targeting regulatory regions of TGFBR2

  • Include controls for both activating (p300) and repressive (HDAC1) chromatin modifiers

  • Compare binding patterns with and without ZNF703 knockdown

  • Correlate binding with gene expression changes

• Functional validation:

  • Use SMAD reporter assays to assess TGFβ pathway activity

  • Rescue experiments combining ZNF703 and TGFBR2 manipulation

  • Epistasis experiments to determine the hierarchy of the regulatory relationship

How should researchers approach contradictory findings when using ZNF703 antibodies?

When confronting contradictory findings with ZNF703 antibodies, researchers should systematically:

• Validate antibody performance:

  • Confirm specificity using positive controls (cell lines with ZNF703 amplification like HCC1500 and MDA-MB-134)

  • Test multiple antibody lots and sources if available

  • Perform knockdown/overexpression validation experiments

• Optimize detection methods:

  • For immunohistochemistry, compare different antigen retrieval conditions

  • For Western blotting, test various lysis buffers as nuclear proteins may require specialized extraction

  • Adjust antibody concentrations based on expression levels in specific samples

• Consider biological variables:

  • Cell context may affect ZNF703 expression patterns (luminal versus basal breast cells)

  • Estrogen stimulation modulates ZNF703 function in ER-positive cells

  • ZNF703 may shuttle between different subcellular compartments

• Reconcile discrepancies through quantification:

  • Use digital image analysis for standardized quantification

  • Apply statistical methods appropriate for the data distribution

  • Consider integrating multiple datasets to identify consistent patterns

• Technical considerations:

  • The immunogen sequence used for antibody generation (PYSKGSGGGDSRKDSGSSSVSSTSSSSSSSPGDKAGFRVPSAACPPFPPHGAPVSASSSSS) should be checked for potential cross-reactivity

How can ZNF703 antibodies be applied in single-cell analysis technologies?

ZNF703 antibodies can be integrated into cutting-edge single-cell technologies through:

• Single-cell proteomics approaches:

  • Mass cytometry (CyTOF) incorporating ZNF703 antibodies conjugated to rare earth metals

  • Imaging mass cytometry for spatial context in tissue sections

  • Single-cell Western blotting to correlate ZNF703 with other proteins at individual cell level

• Spatial transcriptomics integration:

  • Combine ZNF703 immunofluorescence with in situ sequencing

  • Correlate protein localization with mRNA expression patterns

  • Map ZNF703 expression to specific niches within the tumor microenvironment

• Functional single-cell assays:

  • Index sorting followed by colony formation assays to correlate ZNF703 levels with progenitor function

  • Live-cell imaging with fluorescent ZNF703 reporters to track dynamics during cell division and differentiation

• Computational considerations:

  • Develop algorithms to quantify nuclear dot patterns at single-cell resolution

  • Apply machine learning to identify ZNF703-associated cellular phenotypes

  • Integrate protein, transcript, and functional data in unified single-cell models

What are the methodological considerations for studying ZNF703 epigenetic regulatory functions?

Investigating ZNF703's epigenetic regulatory functions requires:

• Comprehensive ChIP-seq approach:

  • Profile ZNF703 genomic binding sites genome-wide

  • Perform parallel ChIP-seq for interacting partners (DCAF7, PHB2, NCOR2)

  • Include histone modification ChIP-seq (H3K4me3, H3K27ac, H3K27me3) to classify active versus repressed regions

• Chromatin accessibility studies:

  • Compare ATAC-seq profiles between control and ZNF703-manipulated cells

  • Focus on regions showing differential accessibility upon ZNF703 overexpression or knockdown

  • Integrate with transcription factor motif analysis

• 3D genome organization:

  • Employ Hi-C or similar technologies to assess if ZNF703 affects chromatin looping

  • Investigate ZNF703's role in enhancer-promoter interactions

  • Consider Chromosome Conformation Capture (3C) for specific loci like TGFBR2

• Chromatin remodeling complex interactions:

  • Expand protein interaction studies to identify potential chromatin remodelers

  • Investigate whether ZNF703 affects nucleosome positioning

  • Assess recruitment of SWI/SNF or other remodeling complexes to ZNF703-bound regions

• Functional validation approaches:

  • Use CRISPR/Cas9 to modify ZNF703 binding sites

  • Employ epigenetic inhibitors to determine if ZNF703 function depends on specific modifications

  • Develop domain mutants to map regions required for epigenetic regulation

How might ZNF703 antibodies contribute to therapeutic development research?

ZNF703 antibodies can advance therapeutic development through:

• Target validation applications:

  • Immunohistochemistry profiling across patient cohorts to identify populations with ZNF703 overexpression

  • Correlation of protein levels with response to current therapies

  • Monitoring changes in ZNF703 expression during treatment resistance development

• Drug discovery support:

  • Develop cell-based assays using ZNF703 antibodies to screen compound libraries

  • Monitor ZNF703 protein levels, subcellular localization, and complex formation in response to candidate drugs

  • Assess effects on downstream pathways using multiplexed antibody approaches

• Combination therapy rationales:

  • Investigate ZNF703 expression changes in response to standard therapies

  • Develop predictive models for which patients might benefit from ZNF703-targeted approaches

  • Use antibody-based detection to identify synergistic pathway interactions

• Biomarker development:

  • Standardize quantitative ZNF703 immunohistochemistry protocols for clinical application

  • Correlate with established markers like ER, PR, HER2, and Ki67

  • Develop companion diagnostic approaches using validated antibodies