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- Table of Contents
PAX4 · Western blot design guide
Design a Western Blot for PAX4
Real validated PAX4 Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-PAX4 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
PAX4 Western Blot Experimental Design Guide
Expected bands, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~37.8 kDa | |
| Observed band | ~38 kDa | |
| Gel | 10–12% | |
| Negative control | siRNA / KO lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | — | |
| Caveat | Multiple isoforms | |
| Regulation | Kras signaling dn | |
| Isoform | 3 isoform(s) |
Section 1
Real Curated PAX4 Western Blot Protocols
Literature-validated Western blot parameters for PAX4 — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | human HL-60 , Lane 2: rat thymus , Lane 3: mouse thymus . After electrophoresis, proteins were transferred to a nitrocellulose membrane at 150 mA for 50-90 minutes. Blocked the membrane with 5% non-fat milk/TBS for 1.5 hour at RT. The membrane was incubated with rabbit anti-PAX4 antigen affinity purified polyclonal antibody (Catalog # A03165-2) at 0.5 μg/mL overnight at 4°C, then washed with TBS-0.1%Tween 3 times with 5 minutes each and probed with a goat anti-rabbit IgG-HRP secondary antibody at a dilution of 1:5000 for 1.5 hour at RT. The signal is developed using an Enhanced Chemiluminescent detection (ECL) kit (Catalog # EK1002) with Tanon 5200 system. A specific band was detected for PAX4 at approximately 38 kDa. The expected band size for PAX4 is at 38 kDa |
| Gel % | 10–12% |
| Load | 30 ug |
| Transfer | nitrocellulose membrane, 150 mA, 50–90 min |
| Membrane | nitrocellulose |
| Blocking | 5% non-fat milk / TBS, 1.5 h RT |
| Primary antibody | 0.5 µg/mL |
| Primary incubation | overnight at 4 °C |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 |
| Wash | TBS-0.1% Tween, 3 × 5 min |
| Detection | ECL |
| Exposure / imaging | Tanon 5200 |
| Observed band | 38 kDa |
Section 2
What Is the Expected PAX4 Western Blot Band Size?
PAX4 has a 37.8 kDa predicted mass and runs at essentially the same ~38 kDa on blots, since it lacks glycosylation, disulfide bonds, or cleavage that would shift its size.
| single band near 38 kDa | matches the predicted 37.8 kDa PAX4 mass, consistent with no glycosylation or proteolytic processing |
| one or two faint additional bands close to the main ~38 kDa band | reflects the three annotated PAX4 splice isoforms co-migrating at slightly different apparent sizes |
| signal present in nuclear extract but weak or absent in cytoplasmic fraction | PAX4 is annotated as a nuclear protein, so it concentrates in nuclear rather than cytoplasmic lysate |
| band migrating slightly above the 37.8 kDa predicted mass | the basic, charge-dense paired-box and homeodomain regions can slow SDS-PAGE migration even without covalent modification |
| no shift in band position between reducing and non-reducing conditions | PAX4 has no annotated disulfide bonds, so reduction should not alter its migration |
| sharp band without smearing | absence of annotated glycosylation sites means no heterogeneous glycoform smear is expected |
💡Expected PAX4 appearancePAX4 typically appears as a single band around 38 kDa, matching its predicted 37.8 kDa mass since it carries no glycosylation, disulfide bonds, or proteolytic processing that would shift its apparent size.
| predicted mass (37.8 kDa) | sets the baseline expected migration position, closely matched by the observed ~38 kDa band |
| absence of glycosylation | keeps the band sharp with no upward smear from heterogeneous glycoforms |
| absence of disulfide bonds | no higher-order dimer band should appear regardless of reducing conditions |
| splice isoforms 1, 2, and 3 | can produce closely spaced additional bands if more than one isoform is expressed in the sample |
| no signal peptide or propeptide | the full-length translated protein is the mature form, so no smaller cleaved product is expected |
| nuclear subcellular localization | band intensity depends on efficient nuclear protein extraction, since whole-cell lysis may under-represent PAX4 |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | PAX4 is a nuclear transcription factor with restricted expression, and standard whole-cell lysis may not adequately extract nuclear protein | use a nuclear-enriched lysis protocol and confirm the sample expresses PAX4 before concluding the antibody failed |
| Multiple bands | the three annotated PAX4 splice isoforms differ slightly in sequence and can resolve as closely spaced bands | compare the pattern against known isoform sizes and use isoform-specific detection if identity needs confirming |
| Weak or no signal | PAX4 expression is limited to a narrow developmental and cell-type window, so many samples have little to detect | include a positive control lysate known to express PAX4, such as an islet or beta-cell line |
| Band higher than expected | the basic paired-box and homeodomain regions can cause anomalously slow SDS-PAGE migration without any covalent modification | verify band identity with a knockdown or knockout control rather than assuming a modification |
| Fragments below expected size | nuclear transcription factors are susceptible to proteolytic degradation during lysate preparation | add fresh protease inhibitors and keep samples cold throughout extraction and handling |
Experiment evidence
Western blot images showing PAX4 band
A03165-2 · PAX4
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for PAX4 Western blot
🧪For positive controls for PAX4 in Western blot, you can use a PAX4-overexpressing cell lysate (e.g., HEK293 cells transiently transfected with a PAX4 expression construct), since the Human Protein Atlas reports no confirmed endogenous positive tissue or cell line for this protein.
Positive control: PAX4-transfected HEK293 lysate
Negative control: ubiquitously expressed; use siRNA knockdown or KO line
Loading controls: Alongside PAX4, run GAPDH and β-actin as loading controls plus a total-protein stain (e.g., stain-free gel, Ponceau S, or REVERT) to confirm even loading and transfer.
⚠️Feasibility: With no HPA expression data available and PAX4 being a low-abundance nuclear transcription factor, endogenous detection in standard tissue lysates is unreliable, so an overexpression lysate paired with a knockdown/KO negative control is the most feasible validation strategy.
Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Section 3
Advanced PAX4 Western Blot Tips
Deeper troubleshooting and optimisation questions for PAX4, answered from its protein features.
Does PAX4 run at its predicted molecular weight?
Yes. PAX4 has a predicted mass of 37.8 kDa, and the commonly observed band sits at approximately 38 kDa, showing close agreement. No signal peptide, propeptide, or glycosylation is annotated, so no major shift from processing or post-translational modification is expected for the primary isoform.
Why might PAX4 blots show more than one band?
UniProt lists three annotated PAX4 isoforms arising from alternative splicing. Additional bands near 38 kDa likely represent these isoforms rather than nonspecific binding or degradation. Confirm identity by comparing band pattern across tissues known to express different isoform ratios and checking against the immunogen region used.
When is PAX4 expression induced in cells or tissue?
PAX4 is a developmental transcription factor with roles in pancreatic islet cell differentiation, linked to diabetes mellitus. Expression is expected mainly in developing or differentiating endocrine pancreas tissue rather than constitutively, so use relevant differentiation-stage samples or islet-derived tissue as positive controls.
How should blocking be optimized for PAX4 detection?
As a nuclear, DNA-binding homeodomain protein, PAX4 extracts require full nuclear lysis (RIPA or nuclear extraction buffer) for efficient release. Use 5% non-fat milk or BSA blocking; if background is high, BSA is preferred since PAX4 antibodies targeting DNA-binding domains can show nonspecific milk-protein interactions.
What transfer method to use for PAX4 Western blot?
At 37.8 kDa predicted mass, standard wet or semi-dry transfer onto PVDF or nitrocellulose works well. Use standard transfer times for mid-size proteins; no extended transfer is needed since PAX4 is not a large or membrane-embedded protein and has no disulfide-linked oligomeric structure reported.
What loading control is appropriate for PAX4 quantitation?
Since PAX4 localizes exclusively to the nucleus, use a nuclear loading control such as Lamin B1 or Histone H3 rather than a whole-cell or cytoplasmic marker like GAPDH. This ensures accurate normalization when working with nuclear extracts or fractionated lysates.
How should unexpected PAX4 bands be interpreted?
Bands deviating from ~38 kDa may reflect one of the three annotated isoforms rather than artifact. Since no glycosylation, disulfide bonds, or extensive PTMs are annotated, unexpected higher or lower bands are more likely isoform-specific or due to incomplete nuclear extraction than chemical modification.
Boster reagents
Best PAX4 Western Blot Antibodies
BosterBio's PAX4 antibodies are among the best-performing WB antibodies on the market — well cited, thoroughly validated, and orthogonally cross-validated against negative tissues and complementary methods.
Real WB data
Anti-PAX4 Antibody Picoband®
Cat # A03165-2
For PAX4 Western blotting, Boster's A03165-2 antibody stands out as our best-performing, well-cited choice — thoroughly validated in-house and orthogonally cross-validated against negative tissue controls and complementary detection methods, ensuring confident, reproducible, specific PAX4 detection in your samples.
Which to pick: Only one PAX4 antibody is catalogued: A03165-2. It's the clear pick, backed by an actual Western blot validation image (SDS-PAGE, 5–20% gradient gel), so choose it with confidence — no alternative SKUs are currently listed for comparison.
Source: BosterBio PAX4 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry O43316.
- Human Protein Atlas. PAX4 tissue expression.