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- Table of Contents
SP3 · Western blot design guide
SP3 Western Blot Planning Guide
Plan a SP3 Western blot around the catalog-observed 81.9 kDa band, image-backed PB9508 evidence, HPA controls, and verified protocol records.
Evidence assembled July 2026 · For research use; verify linked source records and product datasheet before use
SP3 Western Blot Experimental Design Guide
Expected bands, documented protocol parameters, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | 81.9 kDa | |
| Observed band | Not reported — verify product WB image | |
| Gel | 8-10% | |
| Positive control | Breast | |
| Negative control | Epididymis |
Important caveats
Reasons your observed band may differ from the expected size.
| ⓘ | Calculated mass | 81.9 kDa |
| ⓘ | Localization | Nucleus / Nucleus, PML body |
| ⓘ | Processing / PTM | Record-dependent |
| ⓘ | Reactivity | Human / Mouse / Rat |
Section 1
Real Curated SP3 Western Blot Protocols
Start with the molecular-weight rule, then compare verified publication-derived conditions.
| Sample / lysate | Breast |
| Gel % | 8-10% |
| Load | 20-30 µg total protein per lane |
| Transfer | Semi-dry, standard transfer |
| Membrane | 0.45 µm PVDF |
| Blocking | 5% non-fat milk or 5% BSA in TBST |
| Primary | PB9508 at datasheet starting dilution |
| Primary incubation | Overnight at 4 °C with gentle agitation |
| Secondary | Species-matched HRP conjugate at validated dilution |
| Wash | 3 × 5 min in TBST |
| Detection | Chemiluminescent substrate |
| Exposure | Bracket exposures to avoid saturation |
Section 2
What Is the Expected SP3 Western Blot Band Size?
Use the product-observed 81.9 kDa band as the primary planning value and retain the UniProt calculated mass as context.
| 81.9 kDa | Matches the authoritative product WB observation. |
| 81.9 kDa calculated | Use as UniProt context, not as a replacement observed band. |
| Unexpected additional signal | Do not assign identity without orthogonal positive/negative controls. |
💡Expected SP3 appearancePlan around 81.9 kDa and keep the calculated mass as supporting context.
| Catalog-observed band | 81.9 kDa; use this as the primary experimental expectation. |
| Calculated mass | 81.9 kDa from UniProt Q02447; retain as context. |
| Gel selection | 8-10%; shared with the recommended protocol and poster. |
| Specificity check | Compare the lead HPA positive and negative controls with PB9508. |
| Situation | Likely cause | Next action |
|---|---|---|
| 81.9 kDa | Matches the authoritative product WB observation. | Confirm with orthogonal controls and the linked product record. |
| Additional band | May reflect processing, modification, or non-specific signal. | Run a dilution series and compare positive/negative controls. |
| Weak signal | Target abundance or transfer may be limiting. | Verify transfer, increase positive-control abundance, and bracket exposure. |
Experiment evidence
Western blot images showing SP3 band
PB9508 · SP3
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for SP3 Western blot
🧪Use Breast as the first positive-control candidate and Epididymis as the HPA Not detected negative candidate.
Positive control: Breast (High)
Negative control: Epididymis (Not detected)
HPA protein score determines control status; other expression data is supporting context only.
HPA tissue expression evidence for SP3
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 |
|---|---|---|---|---|
| Breast | Reported tissue cells | High | Protein (HPA) | HPA → |
| Lung | Reported tissue cells | High | Protein (HPA) | HPA → |
| Kidney | Reported tissue cells | High | Protein (HPA) | HPA → |
| Endometrium | Reported tissue cells | High | Protein (HPA) | HPA → |
Section 3
Advanced SP3 Western Blot Tips
Deeper troubleshooting and optimisation questions for SP3, answered from its protein features.
Which band should guide the blot?
Use 81.9 kDa, the observation attached to the authoritative PB9508 WB record.
How should calculated mass be interpreted?
Treat the UniProt calculated mass as context; it does not replace the catalog-observed 81.9 kDa expectation.
Which positive control should I start with?
Start with Breast, the lead HPA protein-expression candidate.
Which negative control is defensible?
Use Epididymis as an orthogonal HPA Not detected candidate.
Which gel should I use?
Use 8-10% consistently across the quick facts, protocol table, and poster.
What transfer method to use for SP3 Western blot?
Use the transfer method in the recommended protocol and verify transfer before blocking.
How should PB9508 be started?
Start at the linked datasheet condition and run a three-point primary-antibody dilution test.
Which publication-derived protocols can I compare?
Compare only the supplied target-verified records: PMC8754129, PMC7039131, PMC3006244.
Boster reagents
SP3 Western Blot Reagents
Human/Mouse/Rat-reactive SP3 Western blot reagents with authoritative product imagery.
Real WB data
Anti-SP3 Antibody Picoband®
Cat # PB9508
Only image-backed, WB-validated Human/Mouse/Rat recommendations from the prepared catalog evidence are shown.
Source: prepared picoband-wb product evidence; each card retains its own SKU, URL, observed band, and authoritative WB image.
References
- UniProt Q02447
- Human Protein Atlas — SP3
- PB9508 product record
- PMC8754129 — Caspase-Mediated Cleavage of the Transcription Factor Sp3: Possible Relevance to Cancer and the Lytic Cycle of Kaposi's Sarcoma-Associated Herpesvirus.
- PMC7039131 — The HIV-Tat protein interacts with Sp3 transcription factor and inhibits its binding to a distal site of the sod2 promoter in human pulmonary artery endothelial cells.
- PMC3006244 — Glutamine protects against apoptosis via downregulation of Sp3 in intestinal epithelial cells.