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PARN / Poly(A)-specific ribonuclease PARN · IHC design guide
Design Immunohistochemistry for PARN
Plan PARN staining in paraffin sections using nuclear and cytoplasmic tissue staining as the expected pattern (HPA tissue IHC). This guide covers the catalog antibody's IHC protocol, controls and interpretation, including high staining in colon glandular cells (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PARN 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 | Nuclear and cytoplasmic staining (HPA tissue IHC) | |
| Staining pattern | Nuclear and cytoplasmic staining in most tissues (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A01501-2) | |
| Positive control | Adrenal gland+4 more · see all | |
| Negative control | None in HPA (detected in all 44 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep paraffin-section fixation consistent across samples. (standard IHC practice; not target-specific) | |
| Caveat | Staining and RNA expression have medium consistency (HPA tissue IHC) | |
| Regulation | Low tissue specificity (HPA tissue RNA) | |
| Isoform / epitope | Four isoforms; assess epitope coverage for each (UniProt) |
Section 1
Recommended PARN IHC & IF Protocols
The catalog antibody’s IHC-P protocol (datasheet: A01501-2) is paired with one published PARN IHC protocol for esophageal tissue (PMC10473923).
| Sample | Paraffin-embedded human mammary cancer tissue; fixative not specified (datasheet A01501-2) |
| Fixation | Image fixative and duration unreported (datasheet A01501-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet A01501-2) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01501-2) |
| Primary antibody | Rabbit anti-PARN, 0.5-1μg/ml (datasheet A01501-2) |
| Primary incubation | Overnight at 4 °C (datasheet A01501-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A01501-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | PARN-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and nuclear expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6 heat retrieval (datasheet: A01501-2); try EDTA pH 8 if optimizing retrieval (PMC10473923).
Section 2
What Is the Expected PARN Staining Pattern?
PARN is a nuclear and cytoplasmic protein, with some nuclear PARN in nucleoli; it has no transmembrane segment (UniProt O95453). On paraffin sections, expect staining in many cell types, including strong staining in the listed glandular and respiratory epithelial cells, adipocytes, glial cells, and cerebellar granular layer cells (HPA tissue IHC). HPA rates the tissue pattern Supported, with medium consistency between antibody staining and RNA expression (HPA tissue IHC).
| Nuclear and cytoplasmic staining appears in glandular cells of colon, cervix, or adrenal gland (HPA tissue IHC). | This fits the reported tissue profile and PARN localisation (HPA tissue IHC; UniProt O95453). HPA lists these cells as High, but that label is a tissue observation, not a guaranteed intensity for every section or antibody (HPA tissue IHC). |
| A sharp membrane rim or extracellular deposit dominates, with little nuclear or cytoplasmic signal. | That distribution conflicts with PARN’s reported compartments and lack of a transmembrane segment (UniProt O95453). Treat it as a possible staining artefact; review morphology, detection controls, and the expected compartments before scoring it as PARN (general IHC practice). |
| In a colon section, luminal material stains while glandular cells show no convincing signal. | The distribution misses a listed High cell population (HPA tissue IHC). Consider cross-reactivity or endogenous detection activity, then compare with a no-primary control (general IHC practice). HPA provides no negative-cell list, so an unexpected positive cell alone cannot establish nonspecificity. |
| A pale, widespread haze obscures nuclei and cytoplasm across the section. | The haze prevents assessment of the reported nuclear and cytoplasmic pattern (HPA tissue IHC). Uneven washing, excess detection reagent, or inadequate blocking can cause diffuse background (general IHC practice); use a no-primary control to help locate the source. |
| A technically intact section has no convincing staining in listed High cells, such as bronchial respiratory epithelium. | The result is discordant with HPA’s observed High staining (HPA tissue IHC). Check section preservation, retrieval conditions, antibody application, and detection with suitable controls (general IHC practice). One negative run does not establish biological absence. |
💡Expected PARN appearanceCall a positive result when cell-associated nuclear and cytoplasmic staining is convincing in a listed High population, such as colon glandular cells (HPA tissue IHC); membrane-only or extracellular staining without that pattern is suspect given PARN localisation and topology (UniProt O95453).
| Tissue and cell selection | PARN is described as ubiquitous, and HPA reports cytoplasmic and nuclear expression in most tissues (UniProt O95453; HPA tissue IHC). Use a listed High cell population to judge assay performance; the supplied HPA record names no negative reference tissue. |
| Compartment and processing | PARN has no transmembrane segment or signal peptide and is recorded as one chain spanning residues 1–639 (UniProt O95453). Interpret a membrane-only or extracellular pattern cautiously; these sequence features do not predict section staining intensity. |
| Antibody evidence | HPA lists IHC as Supported for HPA006314, HPA012010, and CAB011673; its tissue profile has medium staining–RNA consistency (HPA antibodies; HPA tissue IHC). This supports comparison with the reported pattern, while leaving discordant staining to be checked experimentally. |
| IF/ICC Q: What localisation should I expect? | A: HPA reports supported nuclear-speckle localisation in ICC-IF, with images from A-431, U-251MG, and U2OS (HPA subcellular). This is a separate IF observation; score paraffin IHC against the broader nuclear and cytoplasmic tissue profile (HPA tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| Listed High cells are unstained. | An assay or section problem is possible when the expected cell population is absent (HPA tissue IHC; general IHC practice). | Confirm tissue identity and morphology, then check the antibody, retrieval, and detection steps against run controls (general IHC practice). Do not infer target absence from this result alone. |
| The section shows membrane-only staining. | A membrane-restricted pattern conflicts with reported nuclear and cytoplasmic localisation and no transmembrane segment (UniProt O95453). | Inspect the staining pattern at higher magnification and compare with a no-primary control; reassess specificity before calling it positive (general IHC practice). |
| Luminal or other unexpected material stains more strongly than the listed High cells. | Cross-reactivity or endogenous chromogenic detection activity may contribute (general IHC practice); HPA’s positive-cell list does not establish a negative-cell rule. | Compare no-primary and detection controls, and review whether the expected cells also show nuclear or cytoplasmic staining (general IHC practice; HPA tissue IHC). |
| Diffuse colour obscures cell boundaries. | Background from blocking, reagent concentration, washing, or detection may mask the expected compartments (general IHC practice; UniProt O95453). | Review the no-primary control and adjust the implicated general IHC step; reassess localisation only after the background clears. |
| Only nuclear staining is visible. | Nuclear localisation is supported, including some nucleolar PARN, but HPA also reports cytoplasmic tissue staining (UniProt O95453; HPA tissue IHC). | Record the observed compartment and compare listed High cells and run controls. Avoid requiring equal nuclear and cytoplasmic intensity, which the supplied sources do not specify. |
| Nuclear speckles seen in IF/ICC are indistinct in chromogenic IHC. | HPA’s supported speckle call comes from ICC-IF, whereas its tissue IHC summary describes nuclear and cytoplasmic expression (HPA subcellular; HPA tissue IHC). | Judge the paraffin section by cell type and broad compartment pattern; consult the separate IF/ICC guide for speckle assessment. |
Experiment evidence
IHC & IF images showing PARN staining
A01501-2 · IHCIHC analysis of PARN using anti-PARN antibody (A01501-2). PARN was detected in paraffin-embedded section of human mammary cancer tissue. Hea
A01501-2 · IHCIHC analysis of PARN using anti-PARN antibody (A01501-2). PARN was detected in paraffin-embedded section of mouse small intestine tissue. He
A01501-2 · IFIF analysis of PARN using anti-PARN antibody (A01501-2). PARN was detected in immunocytochemical section of A549 cell. Enzyme antigen retrie
M01501 · IHCIHC analysis of PARN using anti PARN antibody (M01501). PARN was detected in paraffin-embedded section of human mammary cancer tissue. Heat
M01501 · IFIF analysis of PARN using anti-PARN antibody (M01501). PARN was detected in immunocytochemical section of A549 cells. Enzyme antigen retriev
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000140694-PARN/tissue/cerebral+cortex#imid_2023624
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000140694-PARN/tissue/colon#imid_2023542
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000140694-PARN/tissue/liver#imid_2023551
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000140694-PARN/tissue/kidney#imid_2023552
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006314; green = PARN, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA006314; green = PARN, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PARN IHC & IF
🧪Run adrenal gland first and score glandular cells, which HPA rates High for PARN (HPA: adrenal gland, glandular cells, High). HPA detects PARN in all 44 scored tissues, so use no-primary and isotype controls in place of a negative tissue; cells without specific signal on the positive slide should show counterstain and background only, but no cell type there is a validated internal negative (HPA: no negative tissue rows; UniProt: ubiquitous).
Positive control tissue: Adrenal gland (Glandular cells, HPA High)
Negative control tissue: None in HPA: PARN is detected in all 44 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 PARN in A-431, U-251MG, U2OS, with annotated localisation: Nuclear speckles (supported) (HPA subcellular).
Technical controls: Include a secondary-only slide with the primary omitted, a concentration-matched rabbit IgG isotype control, and, if available, matched PARN-knockout material as a biological specificity control (caption: rabbit anti-PARN primary; standard IHC practice). With the caption’s biotin-based DAB detection, block endogenous peroxidase and assess endogenous biotin background in the adrenal section (caption: SABC/DAB detection; standard IHC practice).
⚠️Feasibility: Paraffin-section IHC is documented with citrate retrieval at pH 6 for 20 minutes, but the selected-SKU caption does not report a fixative; no target-specific fixation window or fixation effect is reported (A01501-2 tissue-IHC caption). HPA ICC-IF supports a nuclear-speckle location, but the supplied evidence does not establish that IF or frozen sections are easier than paraffin IHC (HPA: nuclear speckles, supported; A01501-2 tissue-IHC caption). In adrenal gland, check whether signal follows cells rather than section edges or background, and interpret staining alongside the negative controls (HPA: adrenal gland, glandular cells, High; standard IHC practice).
HPA tissue IHC evidence for PARN
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Medium consistency between antibody staining and RNA expression data.). 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Breast | Adipocytes | High | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: PARN is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced PARN IHC Tips
Troubleshoot PARN staining in paraffin sections by checking retrieval, compartment pattern, background and scoring against the available tissue evidence.
What retrieval conditions should I start with for PARN in paraffin sections?
Start with heat-mediated retrieval in citrate buffer at pH 6 for 20 minutes (datasheet A01501-2). The selected paraffin-section image used these conditions before overnight incubation with 1 μg/mL catalog antibody at 4°C (datasheet A01501-2). If staining is weak, compare retrieval time on adjacent sections while keeping antibody concentration and detection conditions fixed; excessive heating can damage tissue morphology (standard IHC practice). Judge the result by preserved cell boundaries and a plausible nuclear and cytoplasmic pattern, with some nuclear PARN potentially nucleolar, rather than by stain intensity alone (UniProt O95453 localisation; HPA tissue IHC profile).
How should I troubleshoot fixation-related loss of PARN staining?
The selected image identifies a paraffin-embedded section but does not state its fixative, so PARN-specific fixation sensitivity is unknown (datasheet A01501-2 caption). Record the fixative, fixation duration and processing history for each section, then compare similarly handled sections when staining differs (standard IHC practice). If morphology and staining both vary, assess tissue preservation before changing the antibody concentration or retrieval conditions (standard IHC practice). The caption supports citrate retrieval at pH 6 for 20 minutes, but it cannot establish whether a particular fixation condition preserves or masks PARN epitopes (datasheet A01501-2).
Should PARN staining be nuclear, cytoplasmic or nucleolar?
Evaluate nuclear and cytoplasmic staining separately because PARN is reported in both compartments, with some nuclear PARN in the nucleolus (UniProt O95453 localisation; HPA tissue IHC profile). A punctate nuclear component can also be plausible because nuclear speckles are the supported location in HPA subcellular imaging (HPA subcellular). Compare cells within the same section before calling one compartment aberrant, and inspect whether DAB obscures the counterstained nucleus (standard IHC practice). PARN has no transmembrane segment, so an isolated crisp cell-surface rim warrants scrutiny for staining artefact rather than immediate interpretation as PARN distribution (UniProt O95453 topology; standard IHC practice).
Can the PARN isoform or epitope change how I interpret staining?
PARN has 4 recorded isoforms, but the supplied caption does not identify the catalog antibody’s epitope or establish isoform coverage (UniProt O95453 isoforms; datasheet A01501-2 caption). Check an available immunogen or epitope map before claiming that staining represents every isoform (standard IHC practice). The R3H domain spans residues 178–245, and reported modified residues include phosphorylated serines and acetylated lysines; their effect on this antibody’s staining is untested here (UniProt O95453 domains and modified residues). If a second antibody is available, compare compartment patterns on adjacent sections and resolve discordance before assigning an isoform-specific signal (standard IHC practice).
How can IF help assess the PARN pattern seen by chromogenic IHC?
Use IF/ICC as a separate check of compartment distribution: HPA reports supported nuclear-speckle localisation and images from A-431, U-251MG and U2OS cells (HPA subcellular). For tissue multiplexing, pair PARN with a marker that identifies the expected cell type in that specimen, and choose spectrally distinct fluorophores after checking tissue autofluorescence (standard IF practice). Permeabilise for intracellular nuclear and cytoplasmic epitopes, then compare a permeabilised preparation with an appropriate control if signal is weak; PARN has no transmembrane segment (UniProt O95453 topology; standard IF practice). Keep IF findings distinct from the catalog antibody’s paraffin-section DAB result because the supplied caption describes chromogenic IHC (datasheet A01501-2 caption).
What should I check when PARN DAB staining is diffuse?
First compare the stained section with a no-primary control and inspect whether colour tracks tissue edges, folds or damaged areas (standard IHC practice). The selected workflow used 10% goat serum block, biotinylated goat anti-rabbit secondary antibody, a streptavidin-biotin complex and DAB (datasheet A01501-2). Check endogenous peroxidase blocking and, where relevant, endogenous biotin interference before attributing diffuse chromogen to PARN (standard IHC practice). Reduce excessive detection signal by titrating antibody or detection conditions on adjacent sections, while retaining a credible nuclear and cytoplasmic pattern in intact cells (HPA tissue IHC profile; standard IHC practice).
How should I score PARN staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and score nuclear and cytoplasmic compartments separately, since both are reported for PARN (HPA tissue IHC profile; UniProt O95453 localisation). An H-score can combine the percentage of cells at each intensity, while percent-positive cells may be easier to reproduce when intensity varies across a section (standard IHC practice). Normalise each score to eligible, intact cells in the same annotated region; report stained-cell density per mm² only with the measured tissue area and a consistent cell-selection rule (standard IHC practice). Apply one threshold across the comparison set and exclude folds, edges and necrotic regions before comparing specimens (standard IHC practice).
How can I distinguish convincing PARN staining from artefact?
A convincing result places signal within intact cells and can include both nuclear and cytoplasmic staining, with a possible nucleolar or nuclear-speckle component (UniProt O95453 localisation; HPA tissue IHC profile; HPA subcellular). HPA reports high staining in colon glandular cells and bronchial respiratory epithelial cells, which can provide documented cell-type comparisons where those tissues are available (HPA tissue IHC). Treat staining restricted to section edges, necrotic zones or a sharp cell-surface rim cautiously, and compare it with a no-primary control (UniProt O95453 topology; standard IHC practice). Because DAB detection uses an enzyme reaction, review endogenous peroxidase blocking before interpreting widespread brown signal as PARN (standard IHC practice).
Boster reagents
Best PARN / Poly(A)-specific ribonuclease PARN IHC Antibodies
Both anti-PARN antibodies have paraffin-section IHC figures from human mammary cancer tissue and IF/ICC figures from A549 cells (catalog image captions); A01501-2 also has mouse and rat small-intestine IHC figures (A01501-2 IHC captions).
Real IHC data
Anti-PARN Antibody ®
Cat # A01501-2
Real IHC data
Anti-PARN Antibody ® (monoclonal, 11D8)
Cat # M01501
A01501-2 has documented paraffin-section IHC in human mammary cancer and mouse and rat small intestine, plus IF/ICC in A549 cells (A01501-2 image captions). M01501 has documented paraffin-section IHC in human mammary cancer and IF/ICC in A549 and U251 cells (M01501 image captions).
Which to pick: For tissue IHC, choose A01501-2 when mouse or rat evidence matters (A01501-2 IHC captions), or M01501 when a mouse monoclonal antibody is preferred (M01501 catalog: clone 11D8); each has its own human mammary cancer paraffin-section figure (respective IHC captions). For IF/ICC, either has cell images, with M01501 also documented in U251 cells (respective IF captions). For broader listed species reactivity, M01501 includes monkey alongside human, mouse and rat (M01501 catalog reactivity), although its IHC figure shows human tissue only (M01501 IHC caption); the fixative is unreported for both paraffin-section figures (respective IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95453 (PARN_HUMAN, Poly(A)-specific ribonuclease PARN).
- Human Protein Atlas. PARN tissue IHC expression (reliability: Supported).
- Human Protein Atlas. PARN subcellular location (ICC-IF): Localized to the nuclear speckles..
- Human Protein Atlas. PARN antibody validation summary (3 antibodies).
- Poly(A)-specific ribonuclease protein promotes the proliferation, invasion and migration of esophageal cancer cells. World journal of gastroenterology 2023 — PMC10473923.
- Optical Genomic Mapping and Next-Generation Sequencing Identified Retrotransposon Insertion and Missense Variant Disrupting PARN Gene in Dyskeratosis Congenita. Human mutation 2025 — PMC12396913.
- PubMed PMID:9736620 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15616553 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PARN (Poly(A)-specific ribonuclease PARN). Expected localisation Nuclear and cytoplasmic staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A01501-2). Validated IHC antibody: A01501-2 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative None in HPA (detected in all 44 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human mammary cancer tissue; fixative not specified (datasheet A01501-2); 2. Fixation: Image fixative and duration unreported (datasheet A01501-2); 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: Citrate pH 6 , 20 min (datasheet A01501-2); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01501-2); 8. Primary antibody: Rabbit anti-PARN, 0.5-1μg/ml (datasheet A01501-2); 9. Primary incubation: Overnight at 4 °C (datasheet A01501-2). Watch for: Fixation: Keep paraffin-section fixation consistent across samples. (standard IHC practice; not target-specific); Caveat: Staining and RNA expression have medium consistency (HPA tissue IHC); Isoform / epitope: Four isoforms; assess epitope coverage for each (UniProt); Regulation: Low tissue specificity (HPA tissue RNA). Evidence: UniProt O95453, HPA tissue IHC · Supported, HPA ICC-IF · nuclear speckles., Datasheet A01501-2, PMC10473923. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PARN/immunohistochemistry-ihc-guide.