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BBC3 / Bcl-2-binding component 3, isoforms 3/4 · IHC design guide
Design Immunohistochemistry for BBC3
Plan BBC3 chromogenic IHC in paraffin sections using the 2.5–10 μg/mL antibody range validated in human breast tissue (datasheet A04899-1). Assess cytoplasmic staining in the relevant cell populations (HPA tissue IHC), while accounting for 4 isoforms (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BBC3 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 in several tissues (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic in breast glandular cells and lung macrophages (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A04899-1) | |
| Positive control | Breast+4 more · see all | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Use formaldehyde-fixed paraffin sections (selected-SKU IHC image A04899-1) | |
| Caveat | Staining and RNA show only medium consistency (HPA tissue IHC) | |
| Regulation | Regulation is not annotated (UniProt) | |
| Isoform / epitope | 4 isoforms; isoform 3 is nonmitochondrial; epitope coverage is unverified (UniProt) |
Section 1
Recommended BBC3 IHC & IF Protocols
The catalog antibody’s citrate pH 6 IHC protocol (datasheet: A04899-1) is accompanied by one published rat IHC protocol (PMC2173793).
| Sample | Formaldehyde-fixed, paraffin-embedded human breast carcinoma tissue (datasheet A04899-1) |
| Fixation | Image formalin-fixed; duration unreported (datasheet A04899-1); 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 (datasheet A04899-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% serum (datasheet A04899-1) |
| Primary antibody | Rabbit anti-BBC3, 2.5-10 μg/mL (datasheet A04899-1) |
| 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 | BBC3-positive staining in glandular cells of breast (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in several tissues. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6 heat retrieval for the catalog antibody (datasheet: A04899-1). The published rat protocol does not specify retrieval (PMC2173793).
Section 2
What Is the Expected BBC3 Staining Pattern?
Expect BBC3 staining mainly in the cytoplasm of selected cells, including glandular cells in breast, cervix, colon and rectum; lung macrophages; pancreatic endocrine cells; and cerebellar Purkinje cells (HPA: tissue IHC, high). The HPA tissue profile is Approved, with medium consistency between staining and RNA data (HPA: reliability). UniProt annotates no transmembrane segment and does not assign a subcellular location to isoform 3/4 (UniProt Q96PG8: topology, subcellular annotation).
| Cytoplasmic staining stands out in colon glandular cells, with relatively little staining in adjacent cell types (HPA: colon glandular cells, High). | This matches an observed positive tissue and cell type (HPA: colon glandular cells, High). Use the cell type and compartment together when judging a section; tissue name alone is insufficient because HPA reports staining by cell population (HPA: tissue IHC). |
| Strong, predominantly nuclear or sharply membrane-restricted staining replaces the expected cytoplasmic pattern (HPA: cytoplasmic tissue profile). | Treat this as a localisation mismatch requiring control review, rather than as the expected BBC3 result (HPA: tissue IHC; HPA: cytosol, ICC-IF). UniProt reports no transmembrane segment, but that annotation alone cannot identify the cause of an unexpected staining pattern (UniProt Q96PG8: topology). |
| Prominent staining appears in prostate glandular cells while the positive control stains as expected (HPA: prostate glandular cells, Not detected). | This conflicts with the reported HPA cell pattern and warrants investigation for antibody cross-reactivity or endogenous detection activity (HPA: prostate glandular cells, Not detected; general IHC practice). A Not detected HPA result is a comparison point, not proof that every specimen must be negative (HPA: tissue IHC). |
| Weak, even chromogen covers many cells or the section without a clear cytoplasmic cell pattern (general IHC practice). | Diffuse staining is background until controls support a cell-specific result (general IHC practice). Compare a section lacking primary antibody and inspect the counterstain, detection reagents and wash steps before assigning BBC3 positivity (general IHC practice). |
| No signal appears in colon glandular cells or lung macrophages selected as positive reference populations (HPA: both cell types, High). | First check that the expected cells are present and the staining run worked; absence of signal alone does not establish biological absence (general IHC practice). HPA reports high staining in these populations, while its overall tissue IHC reliability is Approved with medium RNA consistency (HPA: tissue IHC). |
💡Expected BBC3 appearanceCall a positive result when identifiable glandular cells, lung macrophages, pancreatic endocrine cells or Purkinje cells show distinct cytoplasmic signal, often high in the HPA examples; widespread cell-independent haze or dominant nuclear staining is suspect (HPA: tissue IHC, High; general IHC practice).
| Cell population within a tissue (HPA: tissue IHC) | HPA reports High staining in colon glandular cells and lung macrophages, but Not detected in prostate glandular cells and adipocytes; score the named cells rather than the whole tissue uniformly (HPA: tissue IHC). |
| Strength and reliability of the reference pattern (HPA: reliability) | The tissue profile is Approved with medium staining-to-RNA consistency and low RNA tissue specificity. Treat HPA intensity categories as observed reference patterns, not absolute cutoffs for an individual specimen (HPA: tissue IHC). |
| Isoform and localisation scope (UniProt Q96PG8; HPA: subcellular) | UniProt lists four BBC3 isoforms and says isoform 3 does not localise to mitochondria, unlike isoforms 1 and 2; it leaves isoform 3/4 location unannotated. HPA's approved cytosol call comes from ICC-IF and does not assign a compartment separately to each isoform (UniProt Q96PG8: isoforms, subcellular annotation; HPA: ICC-IF). |
| Assay-specific antibody evidence (HPA: antibodies) | CAB007752 has Approved IHC status, while HPA070403 has Uncertain ICC status and no listed IHC status. Apply each validation label only to its stated assay; the HPA tissue profile does not establish that any substitute antibody reproduces it (HPA: antibodies, tissue IHC). |
| Situation | Likely cause | Next action |
|---|---|---|
| The positive reference section has no visible cytoplasmic signal (HPA: colon glandular cells, High). | The expected cells may be absent from the section, or a general staining step may have failed (general IHC practice). | Confirm the cells in the counterstained section, then check the primary antibody, detection reagents and run controls before interpreting test sections (general IHC practice). |
| The whole section develops pale, uniform chromogen (general IHC practice). | Nonspecific reagent binding, insufficient washing or endogenous detection activity can produce background (general IHC practice). | Compare a section without primary antibody; review blocking, wash steps and any endogenous enzyme block appropriate to the detection system (general IHC practice). |
| Prostate glandular cells stain strongly even though the reference pattern is Not detected (HPA: prostate glandular cells). | Possible cross-reactivity or detection background; specimen biology can also differ from the HPA reference (HPA: tissue IHC; general IHC practice). | Check compartment and cell identity, compare a positive reference and a section without primary antibody, and avoid calling the signal BBC3 solely from colour intensity (general IHC practice). |
| Signal is concentrated in nuclei or along cell borders rather than in the cytoplasm (HPA: tissue IHC). | The pattern disagrees with HPA's cytoplasmic tissue profile; its cause cannot be assigned from location alone (HPA: tissue IHC; general IHC practice). | Review controls, counterstain and morphology, then compare another section or an independently supported antibody result if available (general IHC practice). |
| A tissue has patchy staining that is difficult to score (general IHC practice). | BBC3 staining varies by cell population: HPA reports High in lung macrophages and Medium in skin fibroblasts, while other listed populations are Low or Not detected (HPA: tissue IHC). | Identify the cell type first and record its compartment and intensity separately; compare only with the matching HPA cell population (HPA: tissue IHC; general IHC practice). |
| Can an IF/ICC image confirm the expected IHC pattern? (HPA: ICC-IF, tissue IHC) | HPA approves cytosolic localisation in ICC-IF, but the supplied antibody statuses differ by assay (HPA: subcellular, antibodies). | Use cytosolic IF/ICC as a localisation comparison; judge paraffin-section chromogenic staining against the tissue IHC cell patterns and the IHC antibody's own validation (HPA: subcellular, tissue IHC, antibodies). |
Experiment evidence
IHC & IF images showing BBC3 staining
A04899-1 · IHCImmunohistochemistry Validation of PUMA in Human Breast Carcinoma Immunohistochemical analysis of paraffin-embedded human breast carcinoma t
A04899-1 · IHCImmunohistochemistry Validation of PUMA in Human Breast Tissue Immunohistochemical analysis of paraffin-embedded human breast tissue using a
A04899-1 · IFImmunofluorescence Validation of PUMA in K562 Cells Immunofluorescent analysis of 4% paraformaldehyde-fixed K562 cells labeling PUMA with A0
M04899 · IHCImmunohistochemical analysis of paraffin-embedded human breast cancer, using PUMA Antibody.
M04899 · IFImmunofluorescent analysis of Hela cells, using PUMA Antibody.
M04899-2 · IHCHuman hepatocellular carcinoma was stained with anti-PUMA rabbit antibody
A04899 · IFImmunofluorescence Validation of PUMA in K562 Cells Immunofluorescent analysis of 4% paraformaldehyde-fixed K562 cells labeling PUMA with A0
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000105327-BBC3/tissue/cerebral+cortex#imid_2138088
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000105327-BBC3/tissue/colon#imid_2132182
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000105327-BBC3/tissue/liver#imid_2132183
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000105327-BBC3/tissue/kidney#imid_2132200
HPA · ICC-IF Hep-G2Human Protein Atlas immunofluorescence, Hep-G2, antibody HPA070403; green = BBC3, blue = nucleus, red = microtubules.
HPA · ICC-IF Hep-G2Human Protein Atlas immunofluorescence, Hep-G2, antibody HPA070403; green = BBC3, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BBC3 IHC & IF
🧪Start with breast tissue: glandular cells should stain (HPA: High in breast glandular cells). Run adipose tissue as the negative comparator (HPA: adipocytes Not detected); adipocytes within the breast section, if present, should show only background staining (HPA: adipocytes Not detected).
Positive control tissue: Breast (Glandular cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show BBC3 in Hep-G2, SK-MEL-30, U2OS, with annotated localisation: Cytosol (approved) (HPA subcellular).
Technical controls: Run no-primary (secondary-only) and host-species-matched, clonality-appropriate isotype controls; use a BBC3 knockout cell pellet processed alongside the tissue, or an immunizing-peptide block if available (standard IHC practice). For chromogenic breast sections, quench endogenous peroxidase and assess background before scoring (standard IHC practice).
⚠️Feasibility: No target-specific fixation window or fixation effect is reported; the selected-SKU fixative field says it is unreported, although the caption text mentions formaldehyde (selected-SKU caption and metadata). The caption uses heat retrieval in citrate buffer at pH 6, but does not establish that retrieval is required (selected-SKU caption). The supplied evidence does not establish whether frozen sections or IF/ICC are easier for BBC3; assess background in breast adipocytes when interpreting the IHC slide (HPA: adipocytes Not detected; standard IHC practice).
HPA tissue IHC evidence for BBC3
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — 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 |
|---|---|---|---|---|
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Cerebellum | Purkinje cells | High | Protein (IHC) | HPA → |
| Cervix | Glandular cells | High | Protein (IHC) | HPA → |
| Colon | Glandular cells | High | Protein (IHC) | HPA → |
| Lung | Macrophages | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Kidney | Cells in glomeruli | Not detected | Protein (IHC) | HPA → |
| Liver | Cholangiocytes | Not detected | Protein (IHC) | HPA → |
| Parathyroid gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced BBC3 IHC Tips
Troubleshoot chromogenic IHC for BBC3 isoforms 3/4 in paraffin sections, using the selected antibody’s tissue image and the stated localisation evidence.
What retrieval should I use when BBC3 staining is weak in paraffin sections?
Use heat-mediated citrate buffer at pH 6 for antigen retrieval in paraffin sections (datasheet A04899-1). The selected tissue image used this retrieval with 10 µg/ml primary antibody incubated overnight at 4°C (caption A04899-1). Keep section preparation, heating, cooling and detection consistent while comparing retrieval duration on adjacent sections (standard IHC practice). If staining remains weak, compare an alternative retrieval buffer on matched sections only after checking the documented citrate condition (standard IHC practice). Judge any apparent gain against tissue morphology, no-primary controls and cytoplasmic staining in the relevant cells (HPA: cytoplasmic tissue profile; standard IHC practice).
How should I troubleshoot inconsistent BBC3 staining after fixation?
BBC3-specific sensitivity to fixative choice or fixation duration is unknown because no controlled comparison is supplied (provided evidence). For paraffin IHC, document the fixative, tissue thickness and time in fixative for each specimen before comparing staining (standard IHC practice). Process matched tissue pieces with consistent fixation and the documented citrate retrieval at pH 6 (datasheet A04899-1; standard IHC practice). Check morphology and compare staining within the same cell population, since damaged or poorly processed areas can distort chromogenic scoring (standard IHC practice). Do not assign a fixation effect to isoform 3 or 4 without matched experimental evidence (UniProt Q96PG8: isoforms 3/4; provided evidence).
Should BBC3 isoform 3 staining appear on mitochondria?
Do not require mitochondrial staining for isoform 3: it is reported not to localise to mitochondria, unlike isoforms 1 and 2 (UniProt Q96PG8). The record gives no annotated location for isoforms 3/4 and no transmembrane segment (UniProt Q96PG8). A cytoplasmic IHC pattern is plausible because the tissue profile reports cytoplasmic expression, although it does not establish isoform identity (HPA: tissue IHC profile). Compare staining with an appropriate cellular counterstain and assess whether it fills cytoplasm rather than section edges or extracellular debris (standard IHC practice). Treat a strictly mitochondrial-looking pattern as a prompt to verify antibody epitope and isoform coverage (UniProt Q96PG8; standard IHC practice).
Can this IHC stain distinguish BBC3 isoforms 3 and 4?
The supplied record lists 4 BBC3 isoforms, but supplies no antibody epitope or isoform-specific binding evidence (UniProt Q96PG8; provided evidence). Therefore, a positive chromogenic stain cannot by itself distinguish isoform 3 from 4 or exclude recognition of 1/2 (provided evidence; standard IHC interpretation). Obtain the antibody’s immunogen sequence and map it against each isoform before making an isoform-specific claim (standard IHC practice). Where possible, compare matched sections with an independently validated antibody targeting a different shared or unique sequence (standard IHC practice). Report the result as BBC3 immunoreactivity unless such validation establishes the detected epitope and isoform coverage (standard IHC practice).
How can IF help check which cells carry the BBC3 IHC signal?
On the separate IF/ICC workflow, pair BBC3 with a validated marker for the expected cell type, such as a macrophage marker when examining lung macrophages (HPA: High in lung macrophages; standard IF practice). Choose spectrally separated fluorophores and inspect unstained tissue to avoid confusing autofluorescence with either channel (standard IF practice). Because the reported location is cytosolic and no transmembrane segment is annotated, assess permeabilisation that permits access to intracellular epitopes (HPA: approved cytosol; UniProt Q96PG8 topology; standard IF practice). The antibody’s precise epitope side is not supplied, so confirm accessibility experimentally (provided evidence). Include single-channel and secondary-only controls before interpreting apparent colocalisation (standard IF practice).
What should I check when brown signal spreads beyond BBC3-positive cells?
First compare the stained section with a no-primary control to identify detection-related background (standard IHC practice). The selected tissue image used 10% serum blocking for 1 h at room temperature and an HRP secondary at 1:250 (caption A04899-1). For chromogenic HRP detection, check the peroxidase block, secondary-antibody binding, wash steps and DAB development time on matched sections (standard IHC practice). Reduce primary concentration only after confirming that the documented retrieval at pH 6 and tissue morphology are satisfactory (datasheet A04899-1; standard IHC practice). Diffuse staining across stroma or section edges should not be scored as cellular BBC3 signal (standard IHC practice).
How should I score BBC3 staining across heterogeneous tissue regions? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and region before scoring, then exclude folds, necrosis and section edges using a consistent rule (standard IHC practice). Record the percentage of positive cells and staining intensity, or calculate an H-score from percentages at each intensity (standard IHC practice). Normalise positive-cell counts to the number of eligible cells, or report positive-cell density per mm² of viable tissue (standard IHC practice). Score relevant populations separately because high staining is reported in breast glandular cells and lung macrophages (HPA: tissue IHC profile). Keep retrieval, illumination, DAB development and thresholds consistent across slides, and report controls alongside scores (datasheet A04899-1; standard IHC practice).
How can I separate true BBC3 staining from artefact?
Look for cellular cytoplasmic staining in the expected population; the tissue profile reports cytoplasmic expression and high signal in breast glandular cells and lung macrophages (HPA: tissue IHC profile). Interpret a mitochondrial-only pattern cautiously for isoform 3, which is reported not to localise to mitochondria (UniProt Q96PG8). Compare viable interiors with edges and necrotic areas, where uneven processing or trapped reagent can produce misleading colour (standard IHC practice). A no-primary control and a peroxidase-block check help identify secondary-reagent or endogenous-enzyme signal (standard IHC practice). Even convincing cellular staining establishes BBC3 immunoreactivity, not isoform 3 or 4 identity without epitope validation (provided evidence; standard IHC interpretation).
Boster reagents
Best BBC3 / Bcl-2-binding component 3, isoforms 3/4 IHC Antibodies
Anti-BBC3 antibodies have IHC images from human breast carcinoma and hepatocellular carcinoma (catalog IHC captions), plus IF images from K562 cells and rat retina (catalog IF captions).
Real IHC data
Anti-PUMA BBC3 Antibody
Cat # A04899-1
Real IHC data
Anti-PUMA BBC3 Rabbit Monoclonal Antibody
Cat # M04899
Real IHC data
Anti-PUMA Rabbit Monoclonal Antibody
Cat # M04899-2
Real IF data
Anti-PUMA BBC3 Antibody
Cat # A04899
A04899-1 shows formaldehyde-fixed, paraffin-embedded human breast carcinoma IHC (A04899-1 IHC caption); M04899 shows paraffin-embedded human breast cancer IHC, with fixative unreported (M04899 IHC caption). M04899-2 shows human hepatocellular carcinoma staining, with processing and fixative unreported (M04899-2 IHC caption); A04899 shows IF in paraformaldehyde-fixed K562 cells (A04899 IF caption).
Which to pick: For tissue IHC, choose A04899-1 when its documented formaldehyde-fixed, paraffin-section workflow fits your sample (A04899-1 IHC caption); M04899 also has a paraffin-section image, but its fixative is unreported (M04899 IHC caption). For IF/ICC, A04899 lists both applications and shows IF in K562 cells (A04899 applications; A04899 IF caption). For planned human, mouse or rat work, M04899 and M04899-2 are monoclonal options that list all three species and IHC/IF applications (M04899 and M04899-2 catalog entries); their pictured IHC samples are human, and M04899-2’s tissue processing and fixative are unreported (M04899 and M04899-2 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q96PG8 (BBC3B_HUMAN, Bcl-2-binding component 3, isoforms 3/4).
- Human Protein Atlas. BBC3 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. BBC3 subcellular location (ICC-IF): Localized to the cytosol..
- Human Protein Atlas. BBC3 antibody validation summary (2 antibodies).
- Marine natural product Methyl mycophenolate inhibits gastric cancer growth through regulating p53 and the downstream pathways. Cancer cell international 2025 — PMC12147254.
- RBM8A promotes gastric cancer progression by binding with UPF3B to induce BBC3 mRNA degradation. International journal of molecular medicine 2025 — PMC12236746.
- Chronic viral infections impaired the growth process of splenic B cells by upregulating Bbc3 and Atf3 in LCMV-CL13 infected mouse model. Virulence 2025 — PMC12688273.
- Gene expression during ER stress-induced apoptosis in neurons: induction of the BH3-only protein Bbc3/PUMA and activation of the mitochondrial apoptosis pathway. The Journal of cell biology 2003 — PMC2173793.
- PubMed PMID:11463392 — UniProt-cited evidence.
- PubMed PMID:15057824 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BBC3 (Bcl-2-binding component 3, isoforms 3/4). Expected localisation Cytoplasmic staining in several tissues (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A04899-1). Validated IHC antibody: A04899-1 at 2.5-10 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Breast (Glandular cells); negative Adipose tissue. IHC-P workflow on paraffin sections. Protocol steps: 1. Sample: Formaldehyde-fixed, paraffin-embedded human breast carcinoma tissue (datasheet A04899-1); 2. Fixation: Image formalin-fixed; duration unreported (datasheet A04899-1); 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 (datasheet A04899-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% serum (datasheet A04899-1); 8. Primary antibody: Rabbit anti-BBC3, 2.5-10 μg/mL (datasheet A04899-1); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Use formaldehyde-fixed paraffin sections (selected-SKU IHC image A04899-1); Caveat: Staining and RNA show only medium consistency (HPA tissue IHC); Isoform / epitope: 4 isoforms; isoform 3 is nonmitochondrial; epitope coverage is unverified (UniProt); Regulation: Regulation is not annotated (UniProt). Evidence: UniProt Q96PG8, HPA tissue IHC · Approved, HPA ICC-IF · cytosol., Datasheet A04899-1, PMC2173793. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BBC3/immunohistochemistry-ihc-guide.