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CBX1 / Chromobox protein homolog 1 · IHC design guide
Design Immunohistochemistry for CBX1
Plan chromogenic CBX1 IHC in paraffin sections with a nuclear readout (HPA tissue IHC). Start the IHC-validated antibody at 2–5 μg/mL (datasheet A04206-2), then score within defined cell populations (standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
CBX1 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 staining across tissues (HPA tissue IHC) | |
| Staining pattern | Nuclei stain across many cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A04206-2) | |
| Positive control | Bone marrow+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 conditions consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Widespread nuclear staining complicates cell-specific scoring (HPA tissue IHC) | |
| Regulation | No specific staining regulator reported (UniProt) | |
| Isoform / epitope | No annotated isoforms; one 1–185 chain (UniProt) |
Section 1
Recommended CBX1 IHC & IF Protocols
The catalog antibody protocol uses EDTA pH 8.0 retrieval (datasheet A04206-2). Two published CBX1 IHC protocols provide tissue microarray and lymphoma section examples (PMC11461582; PMC10331996).
| Sample | Paraffin-embedded human lung cancer tissue; fixative not specified (datasheet A04206-2) |
| Fixation | Image fixative and duration unreported (datasheet A04206-2); 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 A04206-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A04206-2) |
| Primary antibody | Rabbit anti-CBX1, 2-5 μg/ml (datasheet A04206-2) |
| Primary incubation | Overnight at 4 °C (datasheet A04206-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A04206-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | CBX1-positive staining in hematopoietic cells of bone marrow (HPA tissue IHC: High). HPA tissue profile: Ubiquitous nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet A04206-2); the lymphoma protocol also uses microwave EDTA retrieval but does not specify pH (PMC10331996).
Section 2
What Is the Expected CBX1 Staining Pattern?
CBX1 should appear predominantly in nuclei across many cell types: UniProt places it in the nucleus and reports expression in all adult and embryonic tissues (UniProt P83916). Tissue IHC shows ubiquitous nuclear expression with staining supported by agreement with RNA data (HPA: Supported; ubiquitous nuclear expression). CBX1 has no transmembrane segment, so a membrane pattern is unexpected (UniProt P83916 topology).
| Nuclear staining across several cell types, with strong signal in bone marrow hematopoietic cells. | This fits the reported broad nuclear pattern and a documented high-staining cell population; compare nuclei within the same section when judging intensity (HPA: ubiquitous nuclear expression; High in bone marrow hematopoietic cells). |
| Membrane or predominantly cytoplasmic staining, with little nuclear signal. | The compartment conflicts with the reported nuclear location and absence of a transmembrane segment (UniProt P83916 localization and topology; HPA: ubiquitous nuclear expression). Review detection background and antibody specificity before scoring it as CBX1 (standard IHC practice). |
| Staining appears confined to one cell type while nearby intact nuclei are unstained. | A restricted pattern needs review because CBX1 expression is broad; it may reflect cross-reactivity, endogenous detection activity, or technical variation (UniProt P83916 tissue specificity; HPA: ubiquitous nuclear expression; standard IHC practice). Do not designate the unstained cells biologically negative from this pattern alone. |
| Color covers tissue and spaces between cells, obscuring nuclear boundaries. | Diffuse deposition cannot establish CBX1 localization (HPA: ubiquitous nuclear expression). Excess detection signal or incomplete blocking or washing can produce background; assess a control section processed without primary antibody (standard IHC practice). |
| No nuclear signal in an otherwise intact, known-positive section. | An absent result conflicts with documented high staining in the selected positive cell population, such as bronchial respiratory epithelium (HPA: High in bronchus respiratory epithelial cells). Check tissue identity and assay controls before interpreting the specimen as CBX1-negative (standard IHC practice). |
💡Expected CBX1 appearanceCall positive when nuclei stain in expected cell populations, with potentially strong staining in documented high-expression cells; isolated membrane color or diffuse non-nuclear deposits are suspect (HPA: ubiquitous nuclear expression; High in bone marrow hematopoietic cells; UniProt P83916 topology).
| Tissue and cell context | CBX1 is broadly expressed, while HPA specifically reports high staining in hematopoietic, respiratory epithelial, glial and several other cell populations (UniProt P83916 tissue specificity; HPA: tissue IHC). Use a documented high-staining population to assess an absent result. |
| Cell-cycle context | UniProt reports CBX1 as unassociated with chromosomes during mitosis (UniProt P83916 localization). Judge its expected nuclear pattern in interphase cells; staining on condensed mitotic chromosomes need not match that pattern (UniProt P83916 localization). |
| Antibody validation | CAB012265 has Supported IHC status, whereas HPA071387 has no listed IHC validation in this payload (HPA: antibody validation). Treat an IHC result obtained with HPA071387 as lacking the cited IHC support; validation status alone does not prove every observed deposit is specific. |
| IF/ICC expectation? | In IF/ICC, expect mainly nucleoplasmic and nuclear-body signal (HPA: subcellular ICC-IF, both supported). This describes the separate IF/ICC application; it does not establish how finely nuclear bodies will resolve in chromogenic paraffin IHC. |
| Epitope and retrieval evidence | The supplied record gives CBX1 domains and phosphosites but no antibody epitope or target-specific retrieval response (UniProt P83916 domains and modified residues). Choose retrieval conditions from the antibody's IHC-P instructions, then assess tissue controls; do not infer a CBX1 fixation effect from these records (standard IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Known-positive tissue has no nuclear staining. | A failed staining or detection step is possible when a documented high-staining population is blank (HPA: High in bone marrow hematopoietic cells; standard IHC practice). | Confirm the positive tissue and primary-antibody application, then check retrieval and detection against the antibody's IHC-P instructions and run a suitable positive control (standard IHC practice). |
| Color is widespread and nuclei cannot be distinguished. | Background from blocking, washing or chromogen development may obscure the expected nuclear pattern (HPA: ubiquitous nuclear expression; standard IHC practice). | Inspect a section processed without primary antibody; optimize blocking, washing and detection development using that control (standard IHC practice). |
| Signal appears mainly at cell membranes or in cytoplasm. | This conflicts with CBX1's nuclear location and lack of a transmembrane segment; nonspecific staining is a possibility (UniProt P83916 localization and topology). | Compare nuclear signal in a documented positive tissue and examine a no-primary control before assigning the non-nuclear color to CBX1 (HPA: tissue IHC; standard IHC practice). |
| Only one cell population stains in an otherwise intact section. | The restriction differs from the reported broad expression and may reflect uneven staining or an off-target or endogenous signal (UniProt P83916 tissue specificity; HPA: ubiquitous nuclear expression; standard IHC practice). | Check whether staining is nuclear, compare a documented high-staining cell population, and inspect the no-primary control; avoid declaring adjacent cells negative solely by contrast (HPA: tissue IHC; standard IHC practice). |
| A strongly colored nucleus is seen on a mitotic figure. | CBX1 is reported to be unassociated with chromosomes during mitosis, so interphase nuclear localization does not establish a matching chromosome pattern (UniProt P83916 localization). | Base localization assessment on identifiable interphase nuclei and examine whether color on mitotic figures persists in controls (UniProt P83916 localization; standard IHC practice). |
| An IF/ICC image shows nuclear puncta that seem different from IHC. | HPA reports supported localization in both nucleoplasm and nuclear bodies by ICC-IF; the appearance of these structures can differ between fluorescence images and chromogenic sections (HPA: subcellular ICC-IF; standard microscopy practice). | Interpret the IF/ICC image using nucleoplasmic and nuclear-body localization, and score the paraffin IHC section for nuclear staining using its own controls (HPA: subcellular ICC-IF; HPA: tissue IHC; standard IHC practice). |
Experiment evidence
IHC & IF images showing CBX1 staining
A04206-2 · IHCIHC analysis of CBX1/HP1 beta using anti-CBX1/HP1 beta antibody (A04206-2). CBX1/HP1 beta was detected in a paraffin-embedded section of hum
A04206-2 · IHCIHC analysis of CBX1/HP1 beta using anti-CBX1/HP1 beta antibody (A04206-2). CBX1/HP1 beta was detected in a paraffin-embedded section of hum
A04206-2 · IFIF analysis of CBX1/HP1 beta using anti-CBX1/HP1 beta antibody (A04206-2). CBX1/HP1 beta was detected in an immunocytochemical section of CA
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000108468-CBX1/tissue/cerebral+cortex#imid_3065840
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000108468-CBX1/tissue/colon#imid_3065774
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000108468-CBX1/tissue/liver#imid_3065759
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000108468-CBX1/tissue/kidney#imid_3065760
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB012265; green = CBX1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody CAB012265; green = CBX1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for CBX1 IHC & IF
🧪Run bone marrow first; hematopoietic cells should show nuclear staining (HPA: High in hematopoietic cells; UniProt P83916: nucleus). HPA detects CBX1 in all 45 scored tissues, so there is no supported negative tissue; no-primary and isotype controls carry the negative, and any unstained cells within the positive section should show counterstain without nuclear DAB signal rather than be treated as a known CBX1-negative cell type (HPA: detected in all 45 scored tissues).
Positive control tissue: Bone marrow (Hematopoietic cells, HPA High)
Negative control tissue: None in HPA: CBX1 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 CBX1 in A-431, U-251MG, U2OS, SH-SY5Y, SuSa, with annotated localisation: Nucleoplasm (supported), Nuclear bodies (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control, a concentration- and format-matched rabbit IgG isotype control, and a CBX1-knockout sample as a biological negative (selected-SKU caption: rabbit primary and biotinylated goat anti-rabbit secondary; standard IHC practice). For bone marrow, quench endogenous peroxidase before chromogenic detection and assess endogenous biotin if using the caption’s avidin–biotin detection system (HPA: bone marrow hematopoietic cells; selected-SKU caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the selected-SKU paraffin-section caption does not state a fixative (selected-SKU caption: fixative unreported). That caption documents heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required or that frozen sections are easier (selected-SKU caption: EDTA retrieval). IF can help assess the reported nucleoplasmic and nuclear-body pattern, while bone marrow chromogenic IHC requires attention to endogenous peroxidase and, with SABC detection, endogenous biotin (HPA: supported ICC-IF nucleoplasm and nuclear bodies; HPA: bone marrow hematopoietic cells; selected-SKU caption: SABC with DAB; standard IHC practice).
HPA tissue IHC evidence for CBX1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — High 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 |
|---|---|---|---|---|
| Bone marrow | Hematopoietic cells | 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 → |
| Cerebral cortex | Glial cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: CBX1 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced CBX1 IHC Tips
Troubleshoot CBX1 staining in paraffin sections by checking retrieval, nuclear localisation, controls, and scoring against the documented IHC conditions.
What retrieval should I try first when CBX1 nuclear staining is weak?
Start with heat-mediated retrieval in EDTA pH 8.0 for paraffin sections (datasheet A04206-2). Keep heating conditions consistent across comparison slides, then adjust heating incrementally if nuclear signal remains weak (standard IHC practice). The selected tissue image used 2 μg/ml primary antibody overnight at 4°C after retrieval, providing a documented starting condition (caption A04206-2). Judge recovery by nucleoplasmic and nuclear-body staining, the supported CBX1 locations, rather than diffuse cytoplasmic color (HPA subcellular). Include a section processed without primary antibody to assess background, and inspect tissue morphology after heating (standard IHC practice).
Could fixation explain weak or uneven CBX1 staining?
Target-specific CBX1 sensitivity to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state its fixative (caption A04206-2). Record each specimen’s fixative and fixation duration before comparing nuclear staining between samples (standard IHC practice). Test matched sections with the documented EDTA pH 8.0 heat retrieval and 2 μg/ml primary antibody conditions (caption A04206-2). Examine nuclear detail and section integrity alongside signal, since poor morphology makes chromogenic scoring unreliable (standard IHC practice). Do not assign a weak result to a particular fixation effect without a controlled comparison using the same tissue and detection workflow (standard IHC practice).
Where should convincing CBX1 staining appear in a paraffin section?
Expect predominantly nuclear staining: CBX1 is assigned to the nucleus, with supported nucleoplasmic and nuclear-body localisation (UniProt P83916; HPA subcellular). Evaluate stained nuclei within intact tissue architecture and compare adjacent cell populations under the same detection conditions (standard IHC practice). High staining has been reported in bronchial respiratory epithelial cells and bone-marrow hematopoietic cells, providing reference populations where those tissues are available (HPA tissue IHC). A purely membranous pattern conflicts with CBX1’s lack of a transmembrane segment and its reported nuclear localisation (UniProt P83916). During mitosis, chromosome-associated staining may differ because CBX1 is unassociated with chromosomes at that stage (UniProt P83916).
How do domains and modifications affect interpretation of CBX1 staining?
The supplied record lists 0 isoforms and a 1–185 protein chain, so isoform assignment cannot explain differing nuclear patterns here (UniProt P83916). Its chromo domain spans residues 21–79, and its chromoshadow domain spans 117–175 (UniProt P83916). Reported phosphoserines include positions 89, 91, and 175, but the supplied evidence does not map this antibody’s epitope (UniProt P83916; caption A04206-2). Check the antibody’s immunogen or epitope documentation before attributing a staining change to modification or domain accessibility (standard IHC practice). Use matched retrieval and detection conditions when comparing specimens, so technical variation does not masquerade as epitope variation (standard IHC practice).
How can IF help assess an unexpected chromogenic CBX1 pattern?
Use IF as a separate localisation check when chromogenic IHC gives an uncertain nuclear pattern (standard IHC/IF practice). In bronchus, multiplex CBX1 with a respiratory epithelial marker to identify a reported high-staining cell population (HPA tissue IHC). Select a fluorophore whose signal can be separated from the specimen’s autofluorescence, and include single-marker controls when assessing overlap (standard IF practice). Permeabilise sufficiently for antibody access to the nucleus: CBX1 is nuclear and has no transmembrane segment (UniProt P83916). Inspect nucleoplasm and nuclear bodies against the counterstain, then compare the cellular pattern with IHC; supported IF locations include both compartments (HPA subcellular; standard IF practice).
How can I reduce diffuse brown staining while preserving CBX1 signal?
First compare stained sections with sections processed without primary antibody to locate detection-related background (standard IHC practice). The selected paraffin-tissue workflow used a 10% goat-serum block, biotinylated secondary antibody, streptavidin–biotin detection, and DAB (caption A04206-2). For that detection format, check endogenous biotin and apply a peroxidase block when needed to limit non-target color (standard IHC practice). Keep washes and DAB development consistent, then assess whether background persists in cytoplasm, section edges, or damaged tissue (standard IHC practice). Preserve a nuclear signal during adjustments because CBX1’s documented locations are the nucleoplasm and nuclear bodies (HPA subcellular).
How should I quantify CBX1 chromogenic staining across samples? ⚠ ANSWER MARKED FOR VERIFICATION
Score CBX1 within nuclei of a defined cell population, since its supported tissue pattern is ubiquitous nuclear expression (HPA tissue IHC). Record the percentage of positive nuclei and nuclear intensity, or calculate an H-score from intensity categories 0–3 (standard IHC scoring practice). If cell abundance itself is the outcome, report CBX1-positive nuclei per mm² of evaluable tissue (standard IHC scoring practice). Normalise intensity-based results to the nuclei assessed within each region and report tissue area for density measures (standard IHC scoring practice). Apply one threshold, imaging setup, and region-selection rule across specimens; exclude necrotic or poorly preserved areas before scoring (standard IHC practice).
When is a CBX1-positive result credible rather than artefactual?
A credible result places signal in intact nuclei, including nucleoplasm or nuclear bodies, consistent with supported CBX1 localisation (HPA subcellular). Check the identified cell population: high staining is reported in bronchial respiratory epithelium and bone-marrow hematopoietic cells (HPA tissue IHC). Treat isolated edge staining, necrotic regions, and diffuse cytoplasmic color cautiously, and compare them with interior viable tissue (standard IHC practice). If brown signal persists without primary antibody, investigate endogenous enzyme activity or the biotin-based detection workflow before assigning it to CBX1 (standard IHC practice; caption A04206-2). Interpret differences between tissues against CBX1’s reported ubiquitous nuclear expression rather than requiring one particular tissue to be negative (HPA tissue IHC).
Boster reagents
Best CBX1 / Chromobox protein homolog 1 IHC Antibodies
A04206-2 has paraffin-section IHC images from human lung cancer, thyroid papillary carcinoma, mouse intestine and rat brain (catalog IHC captions), plus IF/ICC imaging in CACO-2 cells (catalog IF caption).
Real IHC data
Anti-CBX1/HP1 beta Antibody ®
Cat # A04206-2
A04206-2 is listed for IHC in human, mouse and rat, with paraffin-section images from human lung cancer, human thyroid papillary carcinoma, mouse intestine and rat brain (catalog applications, reactivity and IHC captions). The same SKU is listed for human IF and has a CACO-2 cell image (catalog applications, reactivity and IF caption).
Which to pick: For paraffin-section tissue IHC, choose A04206-2; its own captions document EDTA retrieval at pH 8.0 and primary antibody at 2 μg/ml, while the fixative is unreported (catalog IHC captions). For IF/ICC, A04206-2 has a CACO-2 cell image and a listed human IF concentration of 5 μg/ml (catalog IF caption and datasheet). For cross-species IHC, A04206-2 lists human, mouse and rat reactivity and has paraffin-section images for all three species; its host is rabbit and its clonality is unreported (catalog reactivity, IHC captions and host/clone fields).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P83916 (CBX1_HUMAN, Chromobox protein homolog 1).
- Human Protein Atlas. CBX1 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. CBX1 subcellular location (ICC-IF): Mainly localized to the nucleoplasm and nuclear bodies..
- Human Protein Atlas. CBX1 antibody validation summary (2 antibodies).
- CBX1 is involved in hepatocellular carcinoma progression and resistance to sorafenib and lenvatinib via IGF-1R/AKT/SNAIL signaling pathway. Hepatology international 2024 — PMC11461582.
- CBX1 as a Prognostic Biomarker and Therapeutic Target in Liver Hepatocellular Carcinoma: Insight into DNA Methylation and Non-Coding RNA Networks from Comprehensive Bioinformatics Analysis. Medicina (Kaunas, Lithuania) 2025 — PMC12195192.
- CBX1 Indicates Poor Outcomes and Exerts Oncogenic Activity in Hepatocellular Carcinoma. Translational oncology 2018 — PMC6074001.
- An integrative bioinformatics investigation and experimental validation of chromobox family in diffuse large B-cell lymphoma. BMC cancer 2023 — PMC10331996.
- PubMed PMID:9169582 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:10460410 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for CBX1 (Chromobox protein homolog 1). Expected localisation Nuclear staining across tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A04206-2). Validated IHC antibody: A04206-2 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Bone marrow (Hematopoietic 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 lung cancer tissue; fixative not specified (datasheet A04206-2); 2. Fixation: Image fixative and duration unreported (datasheet A04206-2); 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 A04206-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A04206-2); 8. Primary antibody: Rabbit anti-CBX1, 2-5 μg/ml (datasheet A04206-2); 9. Primary incubation: Overnight at 4 °C (datasheet A04206-2). Watch for: Fixation: Keep fixation conditions consistent across sections (standard IHC practice; not target-specific); Caveat: Widespread nuclear staining complicates cell-specific scoring (HPA tissue IHC); Isoform / epitope: No annotated isoforms; one 1–185 chain (UniProt); Regulation: No specific staining regulator reported (UniProt). Evidence: UniProt P83916, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to the nucleoplasm and nuclear bodies., Datasheet A04206-2, PMC11461582, PMC10331996. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/CBX1/immunohistochemistry-ihc-guide.