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OAS1 / 2'-5'-oligoadenylate synthase 1 · IHC design guide
Design Immunohistochemistry for OAS1
Plan paraffin IHC for OAS1 using the cytoplasmic tissue pattern (HPA tissue IHC) and its interferon-induced expression (UniProt). Interpret staining with the catalog antibody’s OAS1/3 designation (datasheet A01684-3) and the uncertain tissue staining reliability in mind (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
OAS1 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 | Cytoplasmic staining across tissues (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in diverse tissue cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A01684-3) | |
| Positive control | Adipose tissue+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 sections (standard IHC practice; not target-specific) | |
| Caveat | OAS1/3 antibody limits OAS1-specific scoring (datasheet A01684-3) | |
| Regulation | Interferon induced (UniProt) | |
| Isoform / epitope | Four isoforms; antibody epitope coverage is unspecified (UniProt) |
Section 1
Recommended OAS1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is supplemented by published OAS1 chromogenic IHC methods for lung, mouse spinal cord, and pancreatic tissue (PMC11437775; PMC4690264; PMC9309611).
| Sample | Paraffin-embedded human liver cancer tissue; fixative not specified (datasheet A01684-3) |
| Fixation | Image fixative and duration unreported (datasheet A01684-3); 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 A01684-3); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A01684-3) |
| Primary antibody | Rabbit anti-OAS1, 1:50 recommended; image 2 μg/ml (datasheet A01684-3) |
| Primary incubation | Overnight at 4 °C (datasheet A01684-3) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A01684-3) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | OAS1-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: Ubiquitous cytoplasmic expression. No signal in the no-primary control. |
💡Decision noteStart with EDTA pH 8.0 heat retrieval for the catalog antibody (datasheet A01684-3); the published citrate and trypsin methods used different antibodies (PMC9309611; PMC4690264).
Section 2
What Is the Expected OAS1 Staining Pattern?
OAS1 is observed mainly in the cytoplasm across many tissues (HPA tissue IHC: ubiquitous cytoplasmic expression). High staining is reported in bronchial respiratory epithelium and bone marrow hematopoietic cells, among others (HPA tissue IHC). Cytosol and nucleoplasm are supported IF locations (HPA subcellular). OAS1 has no transmembrane segment (UniProt P00973 topology). Interpret tissue IHC cautiously: its reliability is Uncertain because antibody staining and RNA data have low consistency (HPA tissue IHC).
| Cytoplasmic stain in bronchial respiratory epithelial cells or bone marrow hematopoietic cells, with recognizable cell outlines. | This fits reported High staining in those cells and the broad cytoplasmic tissue profile (HPA tissue IHC). Compare cells within the same section before calling intensity abnormal. A matching pattern supports interpretation, but the tissue IHC evidence remains Uncertain and awaits external verification (HPA tissue IHC). |
| Stain is confined to cell borders or luminal surfaces, with little intracellular signal. | Recheck this as a possible staining artefact: OAS1 has no transmembrane segment, while the reported tissue profile is cytoplasmic (UniProt P00973 topology; HPA tissue IHC). Do not reject nuclear staining solely by location; nucleoplasm is supported by IF, and UniProt also lists nuclear association (HPA subcellular; UniProt P00973 subcellular). |
| Smooth muscle cells stain as strongly as adjacent cells reported High, or an implausibly uniform stain spans unrelated structures. | Smooth muscle cells are reported Low, whereas many other cell types are reported High (HPA tissue IHC). Check for cross-reactivity or endogenous chromogenic activity before assigning the stain to OAS1 (general IHC practice). Broad staining alone is insufficient to reject a result because the reported tissue profile is ubiquitous (HPA tissue IHC). |
| A diffuse haze covers tissue, stroma, and empty spaces, obscuring cell boundaries. | Treat the haze as background until a no-primary control and detection controls are reviewed (general IHC practice). OAS1 can be secreted, so extracellular signal cannot be ruled out by location alone (UniProt P00973 subcellular); nevertheless, haze without identifiable positive cells does not reproduce the reported cytoplasmic tissue pattern (HPA tissue IHC). |
| No cellular signal appears in bronchial respiratory epithelium or bone marrow hematopoietic cells. | Both are reported High by tissue IHC (HPA tissue IHC). First check section quality, retrieval, primary antibody, and detection with controls (general IHC practice). An absent result is not proof of absent OAS1: the HPA tissue IHC assessment is Uncertain, and OAS1 is interferon induced (HPA tissue IHC; UniProt P00973 function). |
💡Expected OAS1 appearanceCall a result consistent when discrete cytoplasmic staining is visible in reported High cell types, such as bronchial respiratory epithelium, while border-only stain or diffuse cell-free haze warrants control review; HPA tissue IHC reliability is Uncertain (HPA tissue IHC; UniProt P00973 topology).
| Tissue and antibody evidence | The tissue profile is broadly cytoplasmic, yet its reliability is Uncertain; both listed antibodies have Uncertain IHC status (HPA tissue IHC; HPA antibodies). Use reported High and Low cells as comparisons, not guaranteed controls. |
| Cellular compartment | Cytosol and nucleoplasm are supported IF locations (HPA subcellular). UniProt additionally lists mitochondrial, microsomal, endoplasmic reticulum, and secreted associations (UniProt P00973 subcellular). Avoid treating a single compartment as mandatory in every preparation. |
| Isoforms and epitope | Four isoforms are listed: p46, p42, p48, and p44 (UniProt P00973 isoforms). The supplied evidence gives no antibody epitope, so it cannot establish which isoforms either IHC antibody detects; do not infer isoform identity from stain location. |
| Processing and topology | The listed chain spans residues 1–400, with no signal peptide, propeptide, or transmembrane segment (UniProt P00973 processing and topology). UniProt also lists a secreted form (UniProt P00973 subcellular); the supplied record does not establish a tissue IHC pattern for that form. |
| IF/ICC? | Supported nucleoplasmic and cytosolic localization is reported, with images from A-431, SK-MEL-30, and U-251MG (HPA subcellular). HPA003657 has Supported ICC status but Uncertain IHC status (HPA antibodies). Interpret IF observations through the separate IF/ICC guide. |
| Antigen retrieval and fixation | Target-specific fixation effects are not established by the supplied assay evidence. Verify with a matched IHC source before attributing a result to fixation. |
| Situation | Likely cause | Next action |
|---|---|---|
| Reported High cells are blank while the counterstain and tissue morphology remain readable. | Primary incubation, retrieval, or detection may have failed (general IHC practice); a High designation is not a guaranteed result because HPA tissue IHC reliability is Uncertain (HPA tissue IHC). | Run a documented positive tissue alongside the specimen and verify antibody dilution, retrieval, detection reagents, and reagent order against the antibody's IHC-P instructions (general IHC practice). |
| Brown signal persists in the no-primary control. | Endogenous enzyme activity or nonspecific detection-reagent binding can create chromogenic signal (general IHC practice). | Review the detection chemistry, apply the appropriate endogenous-activity block, and compare with a no-primary section before scoring OAS1 (general IHC practice). |
| The section has widespread brown haze that hides cell boundaries. | Excess primary or detection reagent, insufficient blocking, or inadequate washing can raise background (general IHC practice). | Adjust blocking, antibody concentration, and washes one variable at a time; retain a no-primary section for comparison (general IHC practice). |
| Only crisp membrane outlines stain, without convincing cytoplasm. | A membrane-only pattern conflicts with the reported cytoplasmic tissue profile and lack of a transmembrane segment (HPA tissue IHC; UniProt P00973 topology). | Inspect no-primary and reagent controls, review morphology, and repeat with a separately validated antibody if available; keep the HPA Uncertain IHC status in view (general IHC practice; HPA antibodies). |
| Smooth muscle stains more strongly than nearby reported High cell types. | This reverses the reported Low smooth-muscle pattern, though tissue IHC reliability is Uncertain (HPA tissue IHC). Cross-reactivity or detection background are possible (general IHC practice). | Compare matched regions and no-primary controls, then seek independent antibody or orthogonal evidence before calling the result OAS1-specific (general IHC practice). |
| Nuclear stain accompanies cytoplasmic signal. | Nucleoplasm and cytosol are both supported IF locations, while tissue IHC is described as cytoplasmic overall (HPA subcellular; HPA tissue IHC). | Record the two compartments separately and check controls; avoid labeling every nuclear signal artefactual or treating IF localization as IHC validation (general IHC practice; HPA antibodies). |
Experiment evidence
IHC & IF images showing OAS1 staining
A01684-3 · IHCIHC analysis of OAS1/3 using anti-OAS1/3 antibody (A01684-3). OAS1/3 was detected in a paraffin-embedded section of human liver cancer tissu
A01684-3 · IHCIHC analysis of OAS1/3 using anti-OAS1/3 antibody (A01684-3). OAS1/3 was detected in a paraffin-embedded section of human liver tissue. Heat
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000089127-OAS1/tissue/cerebral+cortex#imid_5433364
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000089127-OAS1/tissue/colon#imid_5433282
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000089127-OAS1/tissue/liver#imid_5433291
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000089127-OAS1/tissue/kidney#imid_5433276
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA003657; green = OAS1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA003657; green = OAS1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for OAS1 IHC & IF
🧪Run adipose tissue first and look for staining in adipocytes (High; HPA: adipose tissue). HPA detects OAS1 in all 45 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat any unstained cells within the adipose section as internal background references rather than proven OAS1-negative cells (HPA: no negative rows; standard IHC control practice).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: None in HPA: OAS1 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 OAS1 in A-431, SK-MEL-30, U-251MG, with annotated localisation: Nucleoplasm (supported), Cytosol (supported) (HPA subcellular).
Technical controls: Run a secondary-only slide and an irrelevant IgG control matched to the primary antibody’s host species and clonality; use OAS1-knockout material, if available, as a biological specificity control (caption: rabbit primary; standard IHC control practice). Quench endogenous peroxidase before chromogenic detection, and distinguish staining from the empty appearance of adipocyte lipid spaces (standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported, and the selected A01684-3 paraffin-section caption does not state a fixative (selected-SKU caption). That caption reports heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required; the supplied evidence does not establish that frozen sections or IF are easier (selected-SKU caption; HPA: ICC-IF images). Adipocyte lipid spaces can complicate interpretation of chromogenic staining, and the caption calls its primary an anti-OAS1/3 antibody, so confirm OAS1 specificity with the biological control (HPA: adipose tissue; selected-SKU caption; standard IHC practice).
HPA tissue IHC evidence for OAS1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Low consistency between antibody staining and RNA expression data. Pending external verification.). 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 |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | High | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | High | Protein (IHC) | HPA → |
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: OAS1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced OAS1 IHC Tips
Troubleshoot OAS1 staining in paraffin sections using the catalog antibody’s IHC evidence, while accounting for its OAS1/3 label and uncertain tissue staining reliability.
What retrieval should I start with for weak OAS1 staining in paraffin sections?
Start with heat mediated retrieval in EDTA at pH 8.0 for the catalog antibody (datasheet A01684-3). The documented paraffin section workflow then used 10% goat serum, 2 μg/ml primary antibody overnight at 4°C, and peroxidase detection with DAB (datasheet A01684-3). If staining remains weak, compare retrieval duration on adjacent sections while holding antibody concentration and detection constant; excessive heating can damage morphology (standard IHC practice). Include a no primary control and examine intact cells rather than damaged section edges before attributing a stronger signal to improved OAS1 detection (standard IHC practice).
Could fixation explain weak or patchy OAS1 staining?
The selected paraffin section caption does not report its fixative, so target specific fixation sensitivity is unknown (datasheet A01684-3). Record the fixative, fixation duration, tissue thickness, and time before fixation for each specimen, then compare similarly processed sections under the same EDTA pH 8.0 retrieval condition (standard IHC practice; datasheet A01684-3). Uneven penetration or overfixation can change antigen accessibility and morphology, but neither effect has been demonstrated specifically for OAS1 here (standard IHC practice). Use preserved cellular detail, matched processing controls, and a no primary control to separate processing variation from nonspecific chromogenic signal (standard IHC practice).
Which cellular compartments should count as plausible OAS1 staining?
Cytoplasmic staining is plausible because HPA describes a ubiquitous cytoplasmic tissue profile, although it rates tissue staining reliability as uncertain (HPA: tissue IHC). Nucleoplasmic and cytosolic signals also have supported subcellular evidence, while UniProt lists associations with mitochondrial, nuclear, and microsomal fractions (HPA: subcellular; UniProt P00973: subcellular location). Score nuclear and cytoplasmic compartments separately rather than treating any brown deposit within a cell as equivalent OAS1 expression (standard IHC practice). Diffuse staining outside intact cells needs particular scrutiny because the record also lists a secreted form, and extracellular DAB alone cannot establish its identity (UniProt P00973: subcellular location; standard IHC practice).
Can this antibody distinguish OAS1 isoforms or OAS1 from OAS3?
The record lists 4 OAS1 isoforms, p46, p42, p48, and p44, but supplies no epitope map for this antibody (UniProt P00973: isoforms; datasheet A01684-3). Its selected tissue caption calls the reagent anti OAS1/3, so a positive paraffin section cannot by itself assign staining exclusively to OAS1 or to one isoform (datasheet A01684-3). Request epitope and cross reactivity documentation before making an isoform specific claim, and use an independent, appropriately validated reagent if that distinction drives the experiment (standard IHC practice). Keep antibody identity and interpretation explicit in scoring records, especially when comparing specimens with different staining patterns (standard IHC practice).
How should I assess OAS1 by IF alongside a cell identity marker?
For the separate IF assay, pair OAS1 with a validated marker for the expected cell population and assess colocalisation in individual cells, rather than assigning a tissue wide signal to one cell type (standard IF practice). Include single stain controls and choose fluorophores whose emission can be separated from each other and from measured tissue autofluorescence (standard IF practice). Permeabilise sufficiently for antibody access to cytosolic and nucleoplasmic epitopes, since those are supported locations and OAS1 has no annotated transmembrane segment (HPA: subcellular; UniProt P00973: topology; standard IF practice). Verify the IF antibody’s own fixation and epitope guidance before interpreting a missing compartment as biologically absent (standard IF practice).
How can I reduce widespread brown staining without losing cellular signal?
First inspect a no primary section for endogenous peroxidase activity, pigment, or nonspecific DAB deposition; include a peroxidase blocking step in the chromogenic workflow (standard IHC practice). The reported paraffin section example used 10% goat serum, 2 μg/ml primary antibody overnight at 4°C, and DAB detection, which provides a documented starting condition for this SKU (datasheet A01684-3). If background persists, titrate the primary antibody and optimise washing while keeping retrieval and detection consistent across comparison sections (standard IHC practice). Assess whether signal follows intact cellular compartments rather than folds, edges, or damaged regions before scoring it (standard IHC practice).
What is a defensible way to quantify OAS1 IHC across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Predefine the cell population and compartment, then report an H score based on staining intensity and percentage of positive cells, or report percentage positive when intensity grading is unreliable (standard IHC practice). For spatial analyses, count positive cells per mm² of evaluable tissue and normalise to the same cell population or tissue area across specimens (standard IHC practice). Exclude folds, necrosis, and edges using one consistent rule, and keep retrieval, antibody concentration, DAB development, and image acquisition comparable (standard IHC practice). Interpret group differences cautiously because HPA rates OAS1 tissue IHC reliability uncertain owing to low consistency with RNA expression (HPA: tissue IHC).
When is apparent OAS1 positivity more likely to be artefact?
Give more weight to reproducible staining in intact cytoplasm or nuclei than to isolated deposits: cytoplasmic tissue staining and nucleoplasmic or cytosolic localisation have supporting records (HPA: tissue IHC; HPA: subcellular). Compare the stained cells with their morphology and a matched no primary section, especially near cut edges, necrosis, folds, or pigment (standard IHC practice). Endogenous peroxidase can produce DAB signal, so check the peroxidase block and control section before calling diffuse brown staining positive (standard IHC practice). Even convincing cellular staining remains an OAS1/3 antibody result rather than proof of OAS1 alone, and HPA labels tissue staining reliability uncertain (datasheet A01684-3; HPA: tissue IHC).
Boster reagents
Best OAS1 / 2'-5'-oligoadenylate synthase 1 IHC Antibodies
A01684-3 has real IHC images from paraffin-embedded human liver and liver cancer tissue (A01684-3 IHC captions); its catalog lists human/mouse reactivity and IF/ICC applications (A01684-3 catalog).
Real IHC data
Anti-OAS1/3 antibody
Cat # A01684-3
A01684-3 is the only rendered card; its IHC images show paraffin-embedded human liver and liver cancer sections (A01684-3 IHC captions). The catalog lists human/mouse reactivity and IHC, IF, and ICC applications, but supplies no IF image (A01684-3 catalog).
Which to pick: For tissue IHC, choose polyclonal A01684-3: its images document paraffin-embedded human sections, with the fixative unreported (A01684-3 catalog; A01684-3 IHC captions). For IF/ICC, A01684-3 lists both applications, while A01684 lists IF only; neither has a supplied IF image (A01684-3 catalog; A01684 catalog). Both list mouse reactivity, but the supplied IHC examples for A01684-3 are human tissue only (A01684 catalog; A01684-3 catalog; A01684-3 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P00973 (OAS1_HUMAN, 2'-5'-oligoadenylate synthase 1).
- Human Protein Atlas. OAS1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. OAS1 subcellular location (ICC-IF): Localized to the nucleoplasm and cytosol..
- Human Protein Atlas. OAS1 antibody validation summary (2 antibodies).
- Prognostic value and molecular mechanisms of OAS1 in lung adenocarcinoma. BMC pulmonary medicine 2024 — PMC11437775.
- Interferon-stimulated genes-essential antiviral effectors implicated in resistance to Theiler's virus-induced demyelinating disease. Journal of neuroinflammation 2015 — PMC4690264.
- Overexpression of OAS1 Is Correlated With Poor Prognosis in Pancreatic Cancer. Frontiers in oncology 2022 — PMC9309611.
- Three Immune-Related Prognostic mRNAs as Therapeutic Targets for Pancreatic Cancer. Frontiers in medicine 2021 — PMC8047149.
- PubMed PMID:2416561 — UniProt-cited evidence.
- PubMed PMID:3753689 — UniProt-cited evidence.
- PubMed PMID:3754863 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for OAS1 (2'-5'-oligoadenylate synthase 1). Expected localisation Cytoplasmic staining across tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A01684-3). Validated IHC antibody: A01684-3 at 1:50 recommended; image 2 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adipose tissue (Adipocytes); 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 liver cancer tissue; fixative not specified (datasheet A01684-3); 2. Fixation: Image fixative and duration unreported (datasheet A01684-3); 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 A01684-3); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A01684-3); 8. Primary antibody: Rabbit anti-OAS1, 1:50 recommended; image 2 μg/ml (datasheet A01684-3); 9. Primary incubation: Overnight at 4 °C (datasheet A01684-3). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: OAS1/3 antibody limits OAS1-specific scoring (datasheet A01684-3); Isoform / epitope: Four isoforms; antibody epitope coverage is unspecified (UniProt); Regulation: Interferon induced (UniProt). Evidence: UniProt P00973, HPA tissue IHC · Uncertain, HPA ICC-IF · nucleoplasm and cytosol., Datasheet A01684-3, PMC11437775, PMC4690264. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/OAS1/immunohistochemistry-ihc-guide.