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CYP2U1 / Cytochrome P450 2U1 · IHC design guide
Design Immunohistochemistry for CYP2U1
Plan CYP2U1 chromogenic IHC in paraffin sections using lung macrophages as a high-staining reference (HPA tissue IHC). The catalog antibody lists a human IHC dilution of 0.5–1 μg/mL (datasheet); assess cytoplasmic and membranous staining with HPA's uncertain reliability in mind (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CYP2U1 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 and membranous tissue staining (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic/membranous; high in lung macrophages (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | Hippocampus+1 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image PA2022); optimize empirically. | |
| Caveat | Low antibody–RNA concordance makes staining uncertain (HPA tissue IHC) | |
| Regulation | No specific expression regulator reported (UniProt) | |
| Isoform / epitope | 2 isoforms; epitope coverage is unspecified (UniProt) |
Section 1
Recommended CYP2U1 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is accompanied by 1 published breast cancer tissue microarray protocol (PMC7419690).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet PA2022); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat-induced epitope retrieval in citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane antigen) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% normal serum of the secondary host, 30 min, room temperature (standard) |
| Primary antibody | Rabbit anti-CYP2U1, 0.5-1μg/ml (datasheet PA2022) |
| Primary incubation | Overnight at 4 °C (standard) |
| Detection | HRP-polymer secondary, DAB chromogen 5–10 min (standard) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CYP2U1-positive staining in lymphoid tissue of appendix (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic and membranous expression in several tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page antigen retrieval); compare the published pH 8.0 condition if staining is weak (PMC7419690).
Section 2
What Is the Expected CYP2U1 Staining Pattern?
CYP2U1 is a membrane protein associated with the endoplasmic reticulum, microsomes and mitochondrial inner membrane, with 5 annotated transmembrane segments (UniProt Q7Z449 topology and subcellular location). In tissue IHC, expect cytoplasmic and membranous staining in selected cells, including lung macrophages and small intestinal glandular cells (HPA: High in both). Interpret the pattern cautiously: HPA rates tissue IHC reliability Uncertain because antibody staining and RNA expression show low consistency (HPA tissue IHC).
| Distinct cytoplasmic and membranous staining in lung macrophages or small intestinal glandular cells, with nearby structures remaining distinguishable (HPA: High in both cell populations; HPA tissue IHC profile). | This fits the reported tissue pattern and provides a useful positive comparison (HPA tissue IHC). Chromogenic IHC cannot assign the signal to a particular organelle from its appearance alone (general IHC practice). |
| Predominantly nuclear staining, with little cytoplasmic or membranous signal (HPA tissue IHC profile; UniProt Q7Z449 subcellular location). | Treat this as a discordant IHC pattern and investigate background or antibody specificity (HPA tissue IHC profile; UniProt Q7Z449 subcellular location). HPA also reports an uncertain nucleoplasmic location in ICC-IF, so nuclear IF observations require their own interpretation (HPA subcellular ICC-IF). |
| Strong staining in liver cholangiocytes or hippocampal glia, while the intended positive cell population is weak (HPA: Not detected in those cell populations). | This differs from the reported IHC comparisons; assess cell identification, cross-reactivity and endogenous detection activity (HPA tissue IHC; general IHC practice). The HPA observations concern those cell populations, not every cell in either tissue (HPA tissue IHC). |
| Uniform colour across many unrelated cell types, tissue edges or empty areas, obscuring cellular boundaries (general IHC practice). | A diffuse distribution is difficult to reconcile with HPA's cell-specific examples; check blocking, washes, detection reagents and the negative control before scoring CYP2U1 (HPA tissue IHC; general IHC practice). |
| No detectable staining in the selected lung macrophages or small intestinal glandular cells (HPA: High in both cell populations). | First verify that those cells are present and that a positive control develops; then review retrieval, antibody application and detection (general IHC practice). An absent result does not by itself establish absent CYP2U1, particularly given HPA's Uncertain tissue IHC reliability (HPA tissue IHC). |
💡Expected CYP2U1 appearanceCall a result provisionally positive when distinct cytoplasmic and membranous signal is appreciable in HPA High cell populations such as lung macrophages, while isolated dominant nuclear signal or broad cell-independent colour warrants investigation as possible nonspecific staining (HPA tissue IHC; UniProt Q7Z449 subcellular location; general IHC practice).
| Cell population and comparator tissue (HPA tissue IHC). | HPA reports High staining in appendix lymphoid tissue, breast myoepithelial cells, gallbladder glandular cells, lung macrophages, small intestinal glandular cells, smooth muscle cells and splenic white-pulp cells; it reports Not detected in liver cholangiocytes and hippocampal glia (HPA tissue IHC). Choose and score the specified cells rather than judging an entire section as uniformly positive or negative (general IHC practice). |
| Membrane topology and organelle assignment (UniProt Q7Z449 topology and subcellular location). | The 5 annotated transmembrane segments support a membrane-associated expectation (UniProt Q7Z449 topology). ER, microsomal and mitochondrial inner-membrane annotations do not make those compartments visually separable in routine chromogenic IHC (UniProt Q7Z449 subcellular location; general IHC practice). |
| IHC evidence strength and antibody choice (HPA tissue IHC; HPA antibody validation). | Overall tissue IHC reliability is Uncertain, and both listed tissue IHC antibodies, HPA041622 and HPA046754, have Uncertain IHC validation (HPA tissue IHC; HPA antibody validation). Treat agreement with an expected pattern as supportive, then evaluate controls and antibody-specific performance before making a strong localization claim (general IHC practice). |
| Isoforms and epitope coverage (UniProt Q7Z449 isoforms). | UniProt lists 2 isoforms, but the supplied record does not identify an antibody epitope or establish which isoforms an IHC antibody detects (UniProt Q7Z449 isoforms). Check antibody documentation before interpreting a negative result as absence of every CYP2U1 isoform (general IHC practice). |
| IF/ICC Q&A: should Golgi staining match tissue IHC? (HPA subcellular ICC-IF). | HPA calls the Golgi apparatus the approved main ICC-IF location and vesicles an approved additional location; nucleoplasm is uncertain (HPA subcellular ICC-IF). Those cell-image observations differ from the tissue IHC cytoplasmic and membranous profile and UniProt's membrane annotations; assess each assay against its own controls (HPA tissue IHC; UniProt Q7Z449 subcellular location; general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected cell population has no signal, but the positive control also fails (general IHC practice). | The IHC workflow or detection system may have failed; the target cannot be assessed from this run (general IHC practice). | Confirm the intended cells are present, then check retrieval, antibody application, reagent activity and detection using a concurrently processed positive control (general IHC practice). |
| Expected cell population is weak while the positive control develops (general IHC practice). | Assay conditions or antibody performance may limit detection; HPA's positive-cell reports do not guarantee signal in every specimen (HPA tissue IHC; general IHC practice). | Review the antibody's IHC validation and optimize retrieval or antibody concentration with appropriate controls, recording the effect on signal and background (general IHC practice). |
| Widespread granular or diffuse colour obscures the reported cell pattern (HPA tissue IHC; general IHC practice). | Background can arise from incomplete blocking, inadequate washing or excessive detection signal (general IHC practice). | Inspect a negative control; review blocking and washes, then adjust antibody or detection conditions while preserving a positive control (general IHC practice). |
| Colour persists in a control lacking the primary antibody (general IHC practice). | Endogenous detection activity or secondary-reagent binding may contribute to the signal (general IHC practice). | Address the activity relevant to the detection chemistry, review blocking and repeat the control before assigning cellular staining to CYP2U1 (general IHC practice). |
| Strong nuclear signal dominates the tissue IHC section (HPA tissue IHC profile). | The pattern is discordant with HPA's cytoplasmic and membranous tissue profile and UniProt's membrane locations; its cause remains unresolved (HPA tissue IHC; UniProt Q7Z449 subcellular location). | Check negative controls and antibody specificity, then compare staining in reported positive cell populations; do not transfer the uncertain ICC-IF nucleoplasmic annotation directly to tissue IHC (HPA subcellular ICC-IF; general IHC practice). |
| Signal appears in reported negative cells or differs between antibodies (HPA tissue IHC; HPA antibody validation). | Cross-reactivity, detection background or antibody-dependent performance is possible; HPA rates tissue IHC reliability Uncertain (HPA tissue IHC; general IHC practice). | Identify the stained cell type precisely, compare controls and any independently validated antibody result, and report discordance rather than scoring the whole tissue as CYP2U1 positive (general IHC practice). |
Experiment evidence
IHC & IF images showing CYP2U1 staining
PA2022 · IHCAnti-CYP2U1 antibody, PA2022, IHC(P) IHC(P): Human Intestinal Cancer Tissue
PA2022 · IFAnti-CYP2U1 antibody, PA2022, ICC ICC: HELA Cell
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000155016-CYP2U1/tissue/cerebral+cortex#imid_13026683
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000155016-CYP2U1/tissue/colon#imid_13026609
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000155016-CYP2U1/tissue/liver#imid_13026594
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000155016-CYP2U1/tissue/kidney#imid_13026595
![HPA ICC-IF BJ [Human fibroblast] — CYP2U1 (HPA064827)](https://images.proteinatlas.org/64827/1527_B2_1_blue_red_green.jpg)
HPA · ICC-IF BJ [Human fibroblast]Human Protein Atlas immunofluorescence, BJ [Human fibroblast], antibody HPA064827; green = CYP2U1, blue = nucleus, red = microtubules.
![HPA ICC-IF BJ [Human fibroblast] — CYP2U1 (HPA064827)](https://images.proteinatlas.org/64827/1527_B2_2_blue_red_green.jpg)
HPA · ICC-IF BJ [Human fibroblast]Human Protein Atlas immunofluorescence, BJ [Human fibroblast], antibody HPA064827; green = CYP2U1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CYP2U1 IHC & IF
🧪Run lung first and look for staining in macrophages (HPA: High in lung macrophages). Run liver as a negative comparison and score cholangiocytes, which are listed as not detected (HPA: Not detected in liver cholangiocytes); cells designated as internal negatives on the lung slide should show only background staining, but other lung cell types cannot be presumed negative from the supplied HPA row.
Positive control tissue: Appendix (Lymphoid tissue, HPA High)
Negative control tissue: Hippocampus (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show CYP2U1 in BJ [Human fibroblast], SK-MEL-30, U2OS, with annotated localisation: Golgi apparatus (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and an isotype control matched to the primary antibody’s host species, clonality and concentration (standard IHC practice). Use CYP2U1 knockout tissue, if available, as a biological negative, or a peptide-block control if the matching immunogen is available; check lung macrophages for endogenous peroxidase activity or pigment that could mimic chromogenic staining (standard IHC practice).
⚠️Feasibility: The selected PA2022 caption documents paraffin-section IHC in human intestinal cancer tissue but does not report a fixative (PA2022 caption: IHC(P); fixative unreported). No target-specific fixation window or retrieval effect is reported in the supplied evidence, so antigen retrieval requires empirical optimization. Frozen sections and IF cannot be judged easier from these data; lung macrophage autofluorescence may complicate IF interpretation (standard IF practice).
HPA tissue IHC evidence for CYP2U1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Low 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 |
|---|---|---|---|---|
| Appendix | Lymphoid tissue | High | Protein (IHC) | HPA → |
| Breast | Myoepithelial cells | High | Protein (IHC) | HPA → |
| Gallbladder | Glandular cells | High | Protein (IHC) | HPA → |
| Lung | Macrophages | High | Protein (IHC) | HPA → |
| Skin | Fibroblasts | Medium | Protein (IHC) | HPA → |
Section 3
Advanced CYP2U1 IHC Tips
Troubleshoot CYP2U1 staining in paraffin sections by checking retrieval, compartment, cell identity, controls, and the limits of the available evidence.
What retrieval should I start with for CYP2U1 paraffin sections?
Start with citrate buffer at pH 6.0 for heat-induced retrieval at 95–98 °C for 20 min (page retrieval setting). Let sections cool in the buffer, then rinse consistently before blocking and staining so retrieval conditions remain comparable across slides (standard IHC practice). CYP2U1 has 5 annotated transmembrane segments, so retrieval may expose some epitopes differently depending on their location (UniProt Q7Z449 topology). If staining is weak, test a second retrieval condition on matched sections alongside the starting condition, judging both signal and tissue preservation (standard IHC practice).
How should I troubleshoot weak CYP2U1 staining after fixation?
Target-specific sensitivity to fixation is unknown from the supplied evidence, and the PA2022 tissue-IHC caption does not state a fixative (PA2022 caption). Record the actual fixative and fixation duration for each specimen, then compare weak and strong sections processed with the same citrate pH 6.0 retrieval for 20 min (standard IHC practice; page retrieval setting). Check whether morphology and a routine control stain are preserved before changing antibody or detection conditions (standard IHC practice). Do not infer a CYP2U1 fixation effect from tissue staining patterns or from its 5 transmembrane segments (HPA tissue IHC; UniProt Q7Z449 topology).
Which cellular pattern should count as plausible CYP2U1 staining?
In chromogenic sections, evaluate cytoplasmic and membranous staining within identifiable cells, the pattern described for several tissues by HPA (HPA tissue IHC). CYP2U1 is annotated at the endoplasmic reticulum and microsome membranes and the mitochondrial inner membrane, with 5 transmembrane segments (UniProt Q7Z449 localisation and topology). HPA cell imaging instead reports a mainly Golgi location, plus vesicles and an uncertain nucleoplasmic location (HPA subcellular). Document diffuse, punctate, and nuclear staining separately rather than pooling them into one positive score, and compare each with matched negative controls (standard IHC practice; HPA subcellular).
Could isoform or epitope choice explain inconsistent staining?
CYP2U1 has 2 annotated isoforms, but the supplied evidence does not map the catalog antibody’s epitope to either one (UniProt Q7Z449 isoforms; supplied antibody evidence). Ask for the immunogen sequence and align it to both isoforms before claiming that a section detects total CYP2U1 (standard antibody validation practice). The protein has 5 annotated transmembrane segments, so epitope position may also affect access after paraffin processing and citrate pH 6.0 retrieval (UniProt Q7Z449 topology; page retrieval setting). Compare candidate conditions on adjacent sections and retain the same detection chemistry when assessing an epitope-access explanation (standard IHC practice).
How can IF help resolve an ambiguous CYP2U1 IHC pattern?
Use IF as a separate validation experiment and multiplex CYP2U1 with a marker for the cell population being assessed, such as macrophages when investigating lung staining (HPA tissue IHC: high in lung macrophages; standard IF practice). Choose a fluorophore channel with low measured tissue autofluorescence and include single-stain and no-primary controls before interpreting overlap (standard IF practice). If the antibody epitope lies on the cytosolic side of a membrane, test mild permeabilisation such as 0.1% Triton X-100; an epitope within an organelle may need different access conditions (UniProt Q7Z449 topology; standard IF practice). The epitope’s membrane side is unreported, so assess permeabilisation empirically (supplied antibody evidence).
What should I check when CYP2U1 sections show widespread brown signal?
Run no-primary and detection-only controls to identify nonspecific chromogen deposition, and inspect unstained tissue for endogenous pigment (standard chromogenic IHC practice). For peroxidase detection, a 3% hydrogen peroxide block for about 10 min is a general workflow option, followed by thorough rinsing before DAB development (standard chromogenic IHC practice). Compare background with the reported cytoplasmic and membranous CYP2U1 tissue pattern, while recognising that HPA rates its tissue staining reliability uncertain (HPA tissue IHC). Reduce excessive primary concentration or DAB development only after checking retrieval, blocking, and tissue integrity on matched sections (standard IHC practice).
How should I score CYP2U1 staining across tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the scored cell population and compartment before analysis, then report the percentage of positive cells and an intensity-weighted H-score on the conventional 0–300 scale (standard IHC scoring practice). For a sparse population such as lung macrophages, report positive-cell density per mm² of viable tissue as well (HPA tissue IHC: high in lung macrophages; standard IHC scoring practice). Normalise comparisons to the same eligible cell type or viable tissue area, section processing, and exposure or development conditions (standard IHC practice). Record cytoplasmic, membranous, and nuclear signal separately because the localisation sources differ (HPA tissue IHC; HPA subcellular; UniProt Q7Z449 localisation).
How do I distinguish true CYP2U1 signal from artefact?
Prioritise reproducible staining in the expected cell population and a plausible cytoplasmic or membranous compartment, with clean no-primary controls (HPA tissue IHC; standard IHC practice). HPA reports high staining in lung macrophages and small-intestine glandular cells, but rates overall tissue-IHC reliability uncertain because staining and RNA data have low consistency (HPA tissue IHC). Treat isolated nuclear-only signal cautiously: HPA calls nucleoplasmic localisation uncertain, while UniProt annotates membrane-associated locations (HPA subcellular; UniProt Q7Z449 localisation). Exclude section edges, necrotic regions, pigment, and residual endogenous peroxidase from positive-cell counts before applying the same 0–300 H-score across specimens (standard chromogenic IHC practice).
Boster reagents
Best CYP2U1 / Cytochrome P450 2U1 IHC Antibodies
PA2022 has IHC data from human intestinal cancer tissue (IHC image caption) and ICC data from HELA cells (ICC image caption); the catalog lists an IF dilution (catalog: 0.5–1 μg/ml).
Real IHC data
Anti-Cytochrome P450 2U1 CYP2U1 Antibody ®
Cat # PA2022
PA2022 will render with an IHC image of human intestinal cancer tissue in a paraffin section (IHC image caption). PA2022 also has an ICC image of HELA cells (ICC image caption) and lists human reactivity (catalog: Human).
Which to pick: Choose PA2022 for human tissue IHC on paraffin sections (catalog: IHC; IHC image caption: human intestinal cancer tissue, IHC(P)); the fixative is unreported (IHC image caption). For cell based IF/ICC, PA2022 lists ICC and an IF dilution of 0.5–1 μg/ml (catalog: applications and IF dilution), with an ICC image of HELA cells (ICC image caption); clonality is unreported (catalog: no clone specified). No cross species choice is supported: PA2022 lists human reactivity only (catalog: Human).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q7Z449 (CP2U1_HUMAN, Cytochrome P450 2U1).
- Human Protein Atlas. CYP2U1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. CYP2U1 subcellular location (ICC-IF): Mainly localized to the Golgi apparatus. In addition localized to the nucleoplasm and vesicles..
- Human Protein Atlas. CYP2U1 antibody validation summary (3 antibodies).
- Cytochrome P450 2U1 Is a Novel Independent Prognostic Biomarker in Breast Cancer Patients. Frontiers in oncology 2020 — PMC7419690.
- Mechanism of Tetrandrine in Ameliorating Hypoxic Pulmonary Hypertension Vascular Remodeling through Transcriptomics and Metabolomics. Current drug metabolism 2025 — PMC12728530.
- Differential Expression of Prostaglandin I2 Synthase Associated with Arachidonic Acid Pathway in the Oral Squamous Cell Carcinoma. Journal of oncology 2018 — PMC6250001.
- PubMed PMID:14660610 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:14975754 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CYP2U1 (Cytochrome P450 2U1). Expected localisation Cytoplasmic and membranous tissue staining (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: PA2022 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Lymphoid tissue); negative Hippocampus. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet PA2022); 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-induced epitope retrieval in citrate buffer, pH 6.0 , 20 min at 95–98 °C…; 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% normal serum of the secondary host, 30 min , room temperature (standard); 8. Primary antibody: Rabbit anti-CYP2U1, 0.5-1μg/ml (datasheet PA2022); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image PA2022); optimize empirically.; Caveat: Low antibody–RNA concordance makes staining uncertain (HPA tissue IHC); Isoform / epitope: 2 isoforms; epitope coverage is unspecified (UniProt); Regulation: No specific expression regulator reported (UniProt). Evidence: UniProt Q7Z449, HPA tissue IHC · Uncertain, HPA ICC-IF · Mainly localized to the Golgi apparatus. In addition localized to…, Datasheet PA2022, PMC7419690. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CYP2U1/immunohistochemistry-ihc-guide.