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PABPN1 / Polyadenylate-binding protein 2 · IHC design guide
Design Immunohistochemistry for PABPN1
Plan PABPN1 paraffin IHC around widespread nuclear staining (HPA tissue IHC) and a catalog antibody range of 2–5 μg/ml (datasheet A02445-2). Compare high staining appendix glandular cells with low staining skeletal myocytes (HPA tissue IHC), and account for HPA’s multi-gene targeting caution (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PABPN1 Immunohistochemistry Experimental Design Guide
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before staining
| Expected localisation | Predominantly nuclear; tissue IHC shows nuclear staining (UniProt; HPA tissue IHC) | |
| Staining pattern | Widespread nuclear staining across cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02445-2) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific) | |
| Caveat | Staining may reflect proteins from more than one gene (HPA tissue IHC) | |
| Regulation | Ubiquitously expressed (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope differences unspecified (UniProt) |
Section 1
Recommended PABPN1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is supplemented by published PABPN1 staining methods for muscle biopsies (PMC9727945) and paraffin-embedded hepatoblastoma tissues (PMC10520360).
| Sample | Paraffin-embedded human colon cancer tissue; fixative not specified (datasheet A02445-2) |
| Fixation | Image fixative and duration unreported (datasheet A02445-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A02445-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02445-2) |
| Primary antibody | Rabbit anti-PABPN1, 2-5 μg/ml (datasheet A02445-2) |
| Primary incubation | Overnight at 4 °C (datasheet A02445-2) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A02445-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | PABPN1-positive staining in glandular cells of appendix (HPA tissue IHC: High). HPA tissue profile: Ubiquitous nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet: A02445-2); the published hepatoblastoma method reports retrieval without specifying its conditions (PMC10520360).
Section 2
What Is the Expected PABPN1 Staining Pattern?
PABPN1 is predominantly nuclear, with nucleoplasmic and nuclear-speckle localisation; UniProt also reports cytoplasmic shuttling (UniProt Q86U42; HPA: supported subcellular locations). Expect staining across many cell types, with strong staining in several glandular and epithelial populations (UniProt: ubiquitous; HPA: ubiquitous nuclear expression; HPA: High in appendix glandular and bronchial respiratory epithelial cells). HPA rates tissue IHC reliability Supported, with medium agreement between staining and RNA data and a warning that the antibodies may recognise proteins from more than one gene (HPA: tissue IHC reliability).
| Nuclear staining in glandular or respiratory epithelial cells, with visible unstained tissue structures. | This fits the reported distribution: HPA records High staining in appendix glandular cells and bronchial respiratory epithelial cells and describes ubiquitous nuclear expression (HPA: tissue IHC). Judge the signal within identified cells and their nuclei; a uniformly coloured section gives less confidence than a pattern with discernible cellular boundaries (standard IHC practice). |
| Predominantly cytoplasmic or extracellular staining, with little nuclear staining. | This is discordant with the main expected compartment (UniProt Q86U42: predominantly nuclear; HPA: nucleoplasm and nuclear speckles). Cytoplasmic signal alone cannot prove artefact because UniProt also reports cytoplasmic shuttling and mRNP granules (UniProt Q86U42). Check morphology, detection controls and an independently validated antibody before assigning the signal to PABPN1 (standard IHC practice; HPA: cross-gene recognition warning). |
| Strong staining in an unexpected cell population, especially when expected nuclei are faint. | Treat an isolated cell-type claim cautiously: UniProt calls expression ubiquitous, and HPA lists no negative tissue in this payload (UniProt Q86U42: tissue specificity; HPA: tissue IHC). Antibody cross-reactivity or endogenous detection activity can mimic a positive population (HPA: cross-gene recognition warning; standard IHC practice). Confirm cell identity by morphology and inspect appropriate reagent controls (standard IHC practice). |
| Diffuse colour over nuclei, cytoplasm and tissue spaces, without clear cellular boundaries. | This cannot be scored confidently as the expected nuclear pattern (HPA: ubiquitous nuclear expression). General IHC causes include excess primary antibody, insufficient washing, nonspecific detection or residual endogenous activity (standard IHC practice). Compare a no-primary control and review reagent concentrations, washing and blocking before interpreting intensity (standard IHC practice). |
| No nuclear signal in a known-positive appendix or bronchus section. | Absence conflicts with the reported High staining in the specified cell populations (HPA: High in appendix glandular and bronchial respiratory epithelial cells). First verify that those cells are present and that a positive control processed in the same run works (standard IHC practice). A failed control points to assay performance; a working control calls for closer review of the test section and antibody specificity (standard IHC practice; HPA: cross-gene recognition warning). |
💡Expected PABPN1 appearanceCall positive when identifiable glandular or respiratory epithelial cells show clear, often strong nuclear staining (HPA: High in appendix glandular and bronchial respiratory epithelial cells; HPA: ubiquitous nuclear expression); widespread colour without nuclear definition is an unreliable positive (standard IHC practice).
| Compartment and topology | PABPN1 has no transmembrane segment and is predominantly nuclear (UniProt Q86U42: topology and localisation). Expect a cellular nuclear readout rather than membrane outlining (UniProt Q86U42; HPA: ubiquitous nuclear expression). UniProt-reported cytoplasmic shuttling means minor cytoplasmic signal needs context, not automatic rejection (UniProt Q86U42). |
| Tissue and cell selection | Appendix glandular cells and bronchial respiratory epithelial cells are reported High; heart cardiomyocytes and skeletal myocytes are reported Low (HPA: tissue IHC). Low is not a negative control, and no negative tissue is listed in this payload (HPA: tissue IHC). Use a reported High population as the positive reference when assessing a weak section (standard IHC practice). |
| Antibody evidence and specificity | HPA000637 has Supported IHC status; HPA079093 has no IHC status in the supplied list (HPA: antibody validation). HPA also warns that tissue staining may detect proteins from more than one gene and reports only medium consistency with RNA expression (HPA: tissue IHC reliability). An apparently correct location alone therefore does not establish target-specific staining (HPA: tissue IHC reliability). |
| Isoforms and epitope knowledge | UniProt lists three isoforms and an RRM at residues 172–249 (UniProt Q86U42: isoforms and domains). The payload gives no antibody epitope, so it cannot establish which isoforms either antibody detects or predict a retrieval response (UniProt Q86U42; HPA: antibody validation). Record the actual reagent and its IHC validation when comparing sections (standard IHC practice). |
| IF/ICC Q&A: what pattern should I expect? | HPA supports nucleoplasmic and nuclear-speckle localisation in ICC-IF (HPA: subcellular localisation). That agrees with predominant nuclear localisation in UniProt (UniProt Q86U42). This answers the localisation question only; the separate IF/ICC guide covers its assay workflow. |
| Situation | Likely cause | Next action |
|---|---|---|
| High control tissue is blank. | The expected cells may be absent from the section, or the staining run may have failed (HPA: High in appendix glandular and bronchial respiratory epithelial cells; standard IHC practice). | Find the relevant cells on the counterstain, then check a same-run positive control and the primary-antibody and detection steps (standard IHC practice). |
| Signal is mostly cytoplasmic. | PABPN1 can shuttle, but a chiefly cytoplasmic pattern conflicts with its predominant nuclear localisation (UniProt Q86U42; HPA: ubiquitous nuclear expression). Nonspecific staining is another possibility (standard IHC practice). | Check nuclear morphology and no-primary controls; confirm any claimed cytoplasmic pattern with independent target evidence (standard IHC practice; HPA: cross-gene recognition warning). |
| The whole section looks brown or hazy. | Nonspecific detection, excess reagent or incomplete washing can obscure nuclear detail (standard IHC practice). | Inspect a no-primary control and review blocking, antibody concentration, washes and detection timing using the reagent's IHC instructions (standard IHC practice). |
| A surprising cell population stains strongly. | Expression is widespread, while HPA flags possible recognition of proteins from more than one gene; endogenous detection activity can also produce apparent positives (UniProt Q86U42: ubiquitous; HPA: tissue IHC reliability; standard IHC practice). | Confirm cell identity, inspect reagent controls and compare localisation with a separately validated antibody where available (standard IHC practice). |
| Heart or skeletal muscle has weak staining. | HPA reports Low staining in cardiomyocytes and skeletal myocytes (HPA: tissue IHC). Weak staining there alone does not show that the assay failed. | Compare a reported High tissue population processed in the same run before changing assay conditions (HPA: tissue IHC; standard IHC practice). |
| A retrieval change alters staining. | The supplied UniProt and HPA records do not establish a PABPN1-specific fixation or retrieval effect (UniProt Q86U42; HPA: tissue IHC and antibody validation). | Compare the conditions using the same tissue and controls; assess whether nuclear definition and background improve, without attributing the change to a proven PABPN1-specific mechanism (standard IHC practice). |
Experiment evidence
IHC & IF images showing PABPN1 staining
A02445-2 · IHCIHC analysis of PABPN1 using anti-PABPN1 antibody (A02445-2). PABPN1 was detected in a paraffin-embedded section of human colon cancer tissu
A02445-2 · IHCIHC analysis of PABPN1 using anti-PABPN1 antibody (A02445-2). PABPN1 was detected in a paraffin-embedded section of human testis tissue. Hea
A02445-2 · IFIF analysis of PABPN1 using anti-PABPN1 antibody (A02445-2) and anti-Beta Tubulin antibody (M01857-3). PABPN1 was detected in an immunocytoc
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000100836-PABPN1/tissue/cerebral+cortex#imid_222626
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000100836-PABPN1/tissue/colon#imid_222544
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000100836-PABPN1/tissue/liver#imid_222553
HPA · PancreasHuman Protein Atlas IHC, Pancreas. Source: https://www.proteinatlas.org/ENSG00000100836-PABPN1/tissue/pancreas#imid_222512
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA000637; green = PABPN1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA000637; green = PABPN1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PABPN1 IHC & IF
🧪Run appendix first: its glandular cells are scored High and should stain (HPA: Appendix, glandular cells, High). HPA detects PABPN1 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and expect only background in gland lumina and extracellular spaces rather than treating any nucleated cell as a validated internal negative (HPA: no negative rows; HPA: PABPN1 detected in all 45 scored tissues).
Positive control tissue: Appendix (Glandular cells, HPA High)
Negative control tissue: None in HPA: PABPN1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show PABPN1 in A-431, U-251MG, U2OS, HAP1, PODO/TERT256, with annotated localisation: Nucleoplasm (supported), Nuclear speckles (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only slide, a concentration-matched nonimmune rabbit IgG isotype control, and PABPN1 knockout material processed in parallel as a biological negative (selected-SKU caption: rabbit primary and anti-rabbit secondary; standard IHC control practice). Block endogenous peroxidase and inspect appendix gland lumina for nonspecific DAB deposition (selected-SKU caption: HRP/DAB detection; HPA: Appendix glandular cells).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected A02445-2 paraffin-section caption does not state a fixative (selected-SKU caption). That colon cancer example uses heat-mediated EDTA retrieval at pH 8.0; it is a starting condition to assess on appendix, where glandular-cell nuclear signal should be distinguished from luminal background (selected-SKU caption; HPA: Appendix glandular cells; UniProt Q86U42 subcellular). Frozen-section performance and any appendix-specific artifact are unreported; ICC-IF supports nucleoplasm and nuclear-speckle localization but does not establish that IF is easier than IHC (HPA subcellular; supplied application evidence).
HPA tissue IHC evidence for PABPN1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data. Caution, targets protein from more than one gene.). 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 |
|---|---|---|---|---|
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Cerebral cortex | Neuropil | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: PABPN1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced PABPN1 IHC Tips
Use nuclear staining as the primary readout for PABPN1 in chromogenic paraffin-section IHC, with attention to retrieval, tissue controls and compartment-specific scoring (UniProt Q86U42; HPA tissue IHC).
How should I optimize retrieval when PABPN1 nuclear staining is weak?
Start with heat-mediated retrieval in EDTA pH 8.0 for paraffin sections (datasheet A02445-2). The selected tissue-IHC image used that retrieval before overnight incubation at 4°C with 2 μg/ml antibody, so reproduce those conditions before changing several variables (datasheet A02445-2). If nuclei remain weak, vary heating time in a small series while keeping section thickness, detection and imaging conditions constant (standard IHC practice). Compare nuclear signal with background in matched sections, because predominantly nuclear localisation provides a compartment-level check on the result (UniProt Q86U42; HPA subcellular). Record the actual heating time and cooling conditions for each run (standard IHC practice).
Could fixation be masking PABPN1 in my paraffin sections?
Target-specific sensitivity to fixation is unknown from the supplied evidence, and the selected paraffin-section caption does not state a fixative (datasheet A02445-2). Record the fixative, fixation duration and processing history for every specimen before attributing weak staining to antigen loss (standard IHC practice). Compare sections processed together under the same EDTA pH 8.0 retrieval and 2 μg/ml primary-antibody conditions used in the selected image (datasheet A02445-2). If staining varies across blocks, change one processing or retrieval variable at a time and assess nuclear signal alongside tissue morphology (standard IHC practice; UniProt Q86U42 localisation). Do not infer fixation tolerance from tissue-expression patterns (HPA tissue IHC).
How should I evaluate cytoplasmic staining when I expect nuclear PABPN1?
Treat nuclear staining as the main compartment-level expectation: PABPN1 is predominantly nuclear, and HPA reports nucleoplasmic and nuclear-speckle localisation (UniProt Q86U42; HPA subcellular). Cytoplasmic signal is biologically possible because PABPN1 shuttles and has been localised to cytoplasmic mRNP granules (UniProt Q86U42). In paraffin-section IHC, first compare cytoplasmic intensity with nuclear signal in intact cells and with matched negative controls (standard IHC practice). Check whether apparent cytoplasmic colour tracks section edges, damaged areas or diffuse background before scoring it as specific (standard IHC practice). Report nuclear and cytoplasmic staining separately, including the proportion of cells in each category (standard IHC practice).
Can this antibody distinguish PABPN1 isoforms or modified epitopes in tissue?
The record lists 3 PABPN1 isoforms, an RRM at residues 172–249, and multiple modified residues, but the supplied antibody caption does not map its epitope (UniProt Q86U42; datasheet A02445-2). Therefore, do not assign a paraffin-section signal to one isoform or modification without independent epitope and specificity evidence (standard IHC interpretation). If staining changes after retrieval, test that change against tissue morphology and background before proposing epitope masking (standard IHC practice). For comparisons between specimens, use the same retrieval, 2 μg/ml antibody concentration and detection conditions as the selected image where practical (datasheet A02445-2; standard IHC practice).
How should I adapt the PABPN1 readout for multiplex IF?
For a separate IF assay, pair PABPN1 with a marker identifying the expected cell population and a nuclear counterstain; glandular cells show high tissue-IHC signal in several listed tissues (HPA tissue IHC). Choose a fluorophore channel with low measured tissue autofluorescence, then verify separation from the companion marker using single-stain controls (standard IF practice). Because PABPN1 is predominantly nuclear and has no transmembrane segment, permeabilise sufficiently for antibody access to the nuclear compartment while preserving nuclear morphology (UniProt Q86U42; standard IF practice). Score nucleoplasmic or speckled signal in the marked cells and compare it with background controls; HPA reports both locations in ICC/IF (HPA subcellular; standard IF practice).
What should I check when DAB obscures PABPN1 nuclear staining?
The selected paraffin-section image used 10% goat-serum block, a peroxidase-conjugated secondary antibody and DAB development (datasheet A02445-2). Apply an endogenous-peroxidase block and inspect a no-primary control to identify enzyme-derived or detection-system colour (standard chromogenic IHC practice). If diffuse colour persists, titrate primary antibody around the demonstrated 2 μg/ml condition and compare sections developed for the same duration (datasheet A02445-2; standard IHC practice). Evaluate background separately in damaged tissue, tissue edges and nuclei, where nonspecific deposit can distort a nuclear readout (standard IHC practice; UniProt Q86U42 localisation). Preserve enough counterstain to identify intact cells without hiding DAB (standard IHC practice).
How should I score PABPN1 across sections with different cell composition? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population before scoring and quantify nuclear PABPN1 within that population, consistent with its predominant nuclear localisation (UniProt Q86U42; standard IHC practice). An H-score can combine the percentage of cells at intensity grades 0–3; alternatively, report the percentage of positive nuclei when intensity grading is unreliable (standard IHC practice). Normalise positive counts to the number of evaluable nuclei in the same region, or report positive nuclei per mm² with the sampled area stated (standard IHC practice). Keep retrieval, DAB development, illumination and scoring thresholds consistent across compared sections, and exclude necrotic or folded regions (standard IHC practice).
How can I distinguish convincing PABPN1 staining from section artefacts?
Convincing staining should have an interpretable nuclear component in intact cells, because PABPN1 is predominantly nuclear and HPA describes ubiquitous nuclear expression (UniProt Q86U42; HPA tissue IHC). A predominantly extranuclear pattern warrants caution, although cytoplasmic localisation can occur in mRNP granules (UniProt Q86U42). Check whether colour follows cut edges, necrotic areas or endogenous enzyme activity using morphology, an endogenous-peroxidase block and a no-primary control (standard chromogenic IHC practice). Compare the expected cell population with the scored cells; HPA reports high staining in several glandular-cell populations and low staining in skeletal-muscle myocytes (HPA tissue IHC). Treat isolated strong deposits without corresponding cellular detail as suspect (standard IHC practice).
Boster reagents
Best PABPN1 / Polyadenylate-binding protein 2 IHC Antibodies
A02445-2 has IHC images from human colon cancer and testis paraffin sections and mouse and rat brain paraffin sections, plus IF images from human cells and tissue and mouse brain (catalog image captions).
Real IHC data
Anti-PABPN1 Antibody ®
Cat # A02445-2
A02445-2 will render with a human colon cancer paraffin-section IHC figure; its other captions show IHC in human testis and mouse and rat brain, and IF in human cells and tissue and mouse brain (A02445-2 image captions). M02445 will render with IHC, IF and ICC listed for human, mouse and rat, but no IHC or IF image captions are supplied (M02445 catalog applications and reactivity; image captions absent).
Which to pick: Choose A02445-2 for paraffin-section IHC because its own captions document staining in human, mouse and rat tissue; the fixative is unreported (A02445-2 IHC image captions). For IF/ICC, A02445-2 has images from human cells and paraffin sections, while M02445 is a rabbit monoclonal with IF/ICC listed but no image captions supplied (A02445-2 IF image captions; M02445 catalog clone, applications and image captions). Both list human, mouse and rat reactivity, but A02445-2 has IHC images across all three species (catalog reactivity; A02445-2 IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q86U42 (PABP2_HUMAN, Polyadenylate-binding protein 2).
- Human Protein Atlas. PABPN1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. PABPN1 subcellular location (ICC-IF): Localized to the nucleoplasm and nuclear speckles..
- Human Protein Atlas. PABPN1 antibody validation summary (2 antibodies).
- Intranuclear inclusions in muscle biopsy can differentiate oculopharyngodistal myopathy and oculopharyngeal muscular dystrophy. Acta neuropathologica communications 2022 — PMC9727945.
- Alternative Splicing of lncRNAs From SNHG Family Alters snoRNA Expression and Induces Chemoresistance in Hepatoblastoma. Cellular and molecular gastroenterology and hepatology 2023 — PMC10520360.
- Polyalanine Expansion in PABPN1 Alters the Structure and Dynamics of Its Nuclear Aggregates in Differentiated Muscle Cells. FASEB journal : official publication of the Federation of American Societies for Experimental Biology 2025 — PMC12186728.
- PABPN1 gene therapy for oculopharyngeal muscular dystrophy. Nature communications 2017 — PMC5380963.
- PubMed PMID:9462747 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:10205180 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PABPN1 (Polyadenylate-binding protein 2). Expected localisation Predominantly nuclear; tissue IHC shows nuclear staining (UniProt; HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02445-2). Validated IHC antibody: A02445-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Glandular cells); negative None in HPA (detected in all 45 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human colon cancer tissue; fixative not specified (datasheet A02445-2); 2. Fixation: Image fixative and duration unreported (datasheet A02445-2); verify before use.; 3. Sectioning: 4–5 µm sections on charged slides (standard); 4. Deparaffinisation: Xylene, graded ethanol series to water (standard); 5. Antigen retrieval: Heat retrieval: EDTA pH 8.0 (datasheet A02445-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02445-2); 8. Primary antibody: Rabbit anti-PABPN1, 2-5 μg/ml (datasheet A02445-2); 9. Primary incubation: Overnight at 4 °C (datasheet A02445-2). Watch for: Fixation: Keep fixation consistent across paraffin sections. (standard IHC practice; not target-specific); Caveat: Staining may reflect proteins from more than one gene (HPA tissue IHC); Isoform / epitope: 3 isoforms; epitope differences unspecified (UniProt); Regulation: Ubiquitously expressed (UniProt). Evidence: UniProt Q86U42, HPA tissue IHC · Supported, HPA ICC-IF · nucleoplasm and nuclear speckles., Datasheet A02445-2, PMC9727945, PMC10520360. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PABPN1/immunohistochemistry-ihc-guide.