ZFHX3 Antibody

What is ZFHX3 and what are its known biological functions?

ZFHX3 (Zinc finger homeobox protein 3), also known as ATBF1 (AT-binding transcription factor 1), is a transcription factor containing four homeodomains and seventeen zinc fingers. It functions as a tumor suppressor in prostate cancer and plays critical roles in regulating myogenic and neuronal differentiation . Recent research has also demonstrated that ZFHX3 orchestrates genome-wide daily gene expression in the suprachiasmatic nucleus (SCN), acting as a key regulator of circadian rhythm . The protein is expressed in multiple tissues including the heart, brain, and prostate, with subcellular localization primarily in the nucleus and cytoplasm .

How do I select the appropriate ZFHX3 antibody for my research?

Selection should be based on:

• Experimental application (IHC, IF/ICC, ELISA, or Western blot)

• Species reactivity needed (human, mouse, etc.)

• Antibody specificity and validation data

• Subcellular localization detection requirements

Most available antibodies show reactivity with human and mouse samples, with optimal dilutions varying by application: IHC (1:150-1:600), IF/ICC (1:200-1:800), and ELISA (1:10000) . Always review validation data and published literature using the antibody for your specific application before making a selection.

What are the recommended protocols for using ZFHX3 antibodies in immunohistochemistry?

For optimal IHC results with ZFHX3 antibodies:

Note that ZFHX3 protein (404 kDa) is relatively large, which may require optimization of extraction and denaturation steps for consistent results .

How can I optimize ZFHX3 detection in immunofluorescence applications?

For successful immunofluorescence detection of ZFHX3:

• Use fresh or properly fixed samples (4% paraformaldehyde recommended)

• Optimize permeabilization conditions (0.1-0.5% Triton X-100 for 10-15 minutes)

• Apply extended blocking (5% BSA or 10% normal serum for 1-2 hours)

• Use ZFHX3 antibody at 1:200-1:800 dilution

• Incubate overnight at 4°C

• Use appropriate fluorophore-conjugated secondary antibodies

• Include DAPI counterstain for nuclear visualization

Known positive cell lines include HeLa and MCF-7 cells, where specific staining is localized to both nuclei and cytoplasm . When analyzing results, expect to see a heterogeneous expression pattern with both nuclear and cytoplasmic signals.

What are the challenges in detecting endogenous ZFHX3 protein in Western blot?

ZFHX3 detection by Western blot presents several challenges:

Additionally, consider using a mixture of detergents (NP-40, Triton X-100, and low SDS) in extraction buffers to improve solubilization of this large nuclear protein .

How do I verify the specificity of my ZFHX3 antibody?

Verify ZFHX3 antibody specificity through multiple approaches:

• Positive and negative tissue controls (breast cancer and prostate cancer tissues are known positives)

• Comparison with RNA expression data

• Knockdown/knockout validation (siRNA or CRISPR)

• Peptide competition assays

• Multiple antibody validation (use different antibodies targeting different epitopes)

• Expected localization pattern (predominantly nuclear with some cytoplasmic staining)

• Detection of appropriate molecular weight band (404 kDa for full-length protein)

When performing these validations, be aware that ZFHX3 may undergo post-translational modifications including ubiquitination, sumoylation, and phosphorylation that could affect detection .

How can I use ZFHX3 antibodies for studying its role in prostate cancer through m6A modification pathways?

Recent research has revealed ZFHX3's role in regulating m6A modification in prostate cancer:

• Experimental design approach:

  • Compare ZFHX3 and FTO expression levels in prostate cancer and normal tissues

  • Perform ZFHX3 knockdown experiments followed by m6A level quantification

  • Use FTO inhibitors to assess rescue effects on cell proliferation

  • Employ MeRIP sequencing to identify m6A-modified targets

• Key findings to validate:

  • ZFHX3 knockdown decreases total m6A levels by enhancing FTO transcriptional activity

  • FTO inhibition rescues the promoting function of ZFHX3 knockdown on cell proliferation

  • E2F2 and CDKN2C are direct targets of FTO-mediated m6A modification

  • ZFHX3 expression is regulated by FTO in an m6A-dependent manner

• Methodological considerations:

  • Use m6A-specific antibodies for MeRIP-seq

  • Include appropriate controls for knockdown experiments

  • Verify changes in m6A levels using both global and gene-specific assays

What is the methodology for using ZFHX3 antibodies in ChIP-seq experiments?

Based on published protocols for ZFHX3 ChIP-seq:

• Tissue collection and crosslinking:

  • Collect tissue samples at appropriate timepoints (e.g., ZT3 and ZT15 for circadian studies)

  • Fix samples with 1% formaldehyde for 15 minutes with gentle shaking

  • Quench with glycine (final concentration 0.125 M)

• Chromatin preparation:

  • Shear crosslinked chromatin using sonication to 200-500 bp fragments

  • Verify fragmentation by agarose gel electrophoresis

• Immunoprecipitation:

  • Use 24 μg sheared chromatin per IP reaction

  • Incubate with 12 μl ZFHX3 antibody and magnetic beads at 4°C overnight

  • Include appropriate IgG controls and input samples

• DNA purification and analysis:

  • Reverse crosslinking and digest with proteinase K

  • Purify DNA using PCR purification reagents

  • Perform qPCR for quality control before sequencing

  • Sequence using appropriate platform (e.g., Illumina, 75 bp single-end reads)

• Data analysis:

  • Process data using FastQC and Trimmomatic

  • Align to reference genome using appropriate aligner

  • Call peaks using MACS algorithm (q < 0.01)

  • Analyze differential binding using Diffbind

  • Annotate peaks using ChIPSeeker

How can I investigate the relationship between ZFHX3 and circadian rhythm regulation?

To study ZFHX3's role in circadian rhythm regulation:

• Experimental design:

  • Collect SCN tissue at multiple timepoints across 24-hour cycle

  • Perform ChIP-seq using ZFHX3 antibodies to identify genome-wide binding sites

  • Conduct RNA-seq following ZFHX3 knockout to assess transcriptional impact

  • Compare binding patterns with histone modifications (H3K4me3, H3K27ac)

• Expected findings:

  • Approximately 60% of ZFHX3 binding sites occur near promoters

  • ZFHX3 deletion affects expression of ~36% of genes in the SCN

  • Loss of ZFHX3 impacts expression of key neuropeptides (Avp, Vip, Grp, Prok2)

  • Genes regulated by ZFHX3 fall into distinct circadian rhythm modules

• Data interpretation framework:

  • Categorize genes into modules based on rhythmicity patterns:

    • Module 1: No rhythm in either condition

    • Module 2: Rhythmic in control but not in ZFHX3-KO

    • Module 3: Gained rhythmicity after ZFHX3-KO

    • Module 4: Rhythmic with no change between conditions

    • Module 5: Rhythmic with changed amplitude or phase

What controls should be included when analyzing contradictory results in ZFHX3 knockdown/knockout studies?

When confronting contradictory results in ZFHX3 studies:

• Essential controls to include:

  • Multiple independent knockdown/knockout methods (siRNA, shRNA, CRISPR)

  • Rescue experiments with ZFHX3 overexpression

  • Time-course analyses (ZFHX3 has time-dependent functions)

  • Cell/tissue-specific validation (ZFHX3 functions differ by context)

  • Verification of knockout efficiency at both mRNA and protein levels

• Common sources of contradictions:

  • Incomplete knockdown of this large protein

  • Compensatory mechanisms activated in complete knockout

  • Context-dependent functions (ZFHX3 regulates different pathways in different tissues)

  • Interactions with specific binding partners that vary between systems

  • Secondary effects due to ZFHX3's broad genomic binding profile (>43,000 sites)

• Resolution strategies:

  • Compare acute versus chronic ZFHX3 depletion

  • Analyze domain-specific functions using truncated constructs

  • Investigate cell-type specific binding partners

  • Examine post-translational modifications affecting ZFHX3 function

How can I address non-specific binding issues when using ZFHX3 antibodies?

To minimize non-specific binding:

Additionally, consider using peptide competition assays with the immunogenic peptide (e.g., synthesized peptide derived from internal region of human ZFHX3) to confirm binding specificity .

What are the best practices for quantifying ZFHX3 expression in tissue samples?

For accurate ZFHX3 quantification:

• IHC Quantification:

  • Use digital image analysis software with appropriate thresholding

  • Score both intensity (0-3) and percentage of positive cells

  • Calculate H-score or QuickScore for semi-quantitative analysis

  • Include internal controls in each batch for normalization

• IF Quantification:

  • Measure nuclear-to-cytoplasmic ratio of ZFHX3 staining

  • Use Z-stack imaging for accurate subcellular localization

  • Apply consistent acquisition parameters across all samples

  • Co-stain with cell-type specific markers for population-specific analysis

• Western Blot Quantification:

  • Use loading controls appropriate for nuclear proteins (e.g., Lamin B1)

  • Apply gradient gels for improved resolution of this large protein

  • Perform densitometry analysis with normalization to controls

  • Consider running reference standards for cross-experiment comparisons

How should I interpret conflicting data between protein and mRNA expression levels of ZFHX3?

When facing discrepancies between ZFHX3 protein and mRNA levels:

• Potential explanations:

  • Post-transcriptional regulation (ZFHX3 is subject to m6A modification)

  • Protein stability differences (ZFHX3 undergoes ubiquitination and proteasomal degradation)

  • Technical limitations in detecting the large ZFHX3 protein

  • Feedback mechanisms (FTO regulates ZFHX3 in an m6A-dependent manner)

  • Cell-cycle dependent regulation

• Validation approaches:

  • Measure protein half-life using cycloheximide chase assays

  • Assess proteasome inhibition effects on ZFHX3 levels

  • Analyze polysome fractions for translation efficiency

  • Examine m6A modifications on ZFHX3 mRNA

  • Check for presence of alternatively spliced isoforms

• Integrated analysis:

  • Combine protein, mRNA, and ChIP data for comprehensive understanding

  • Consider single-cell analyses to account for population heterogeneity

  • Examine temporal dynamics of expression

  • Investigate tissue-specific post-translational modifications