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BRD4 / Bromodomain-containing protein 4 · IHC design guide
Design Immunohistochemistry for BRD4
Plan paraffin BRD4 IHC around its ubiquitous nuclear tissue pattern (HPA tissue IHC). Use the documented human kidney IHC example and compare nuclear staining across consistently handled sections (datasheet: M00123; standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
BRD4 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 | Ubiquitous nuclear staining (HPA tissue IHC) | |
| Staining pattern | Nuclear staining across many cell types (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen) | |
| 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 | Histone deacetylation can release BRD4 from chromatin (UniProt) | |
| Regulation | Deacetylation reduces chromatin binding (UniProt) | |
| Isoform / epitope | 3 isoforms (A, B, C); verify epitope coverage (UniProt) |
Section 1
Recommended BRD4 IHC & IF Protocols
The catalog antibody protocol is accompanied by published BRD4 IHC methods for heart, breast, peripheral nerve, and gastric tissue (PMC12203807; PMC6053709; PMC9278623; PMC5458191).
| Sample | Paraffin-embedded human kidney tissue; fixative not specified (datasheet M00123) |
| Fixation | Image fixative and duration unreported (datasheet M00123); 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 Tris-EDTA buffer, pH 9.0, 20 min at 95–98 °C (standard rule: nuclear 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 monoclonal (clone DBH-2) anti-BRD4, 1:50 (datasheet M00123) |
| 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 | BRD4-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: Ubiquitous nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with Tris-EDTA pH 9.0 retrieval at 95–98 °C for 20 min (page antigen-retrieval specification); use the cited retrieval conditions when reproducing a paper.
Section 2
What Is the Expected BRD4 Staining Pattern?
BRD4 is nuclear and chromatin associated (UniProt O60885). Expect broad nuclear staining, including in adipocytes, glandular cells and hematopoietic cells (HPA: High in each). HPA rates its tissue IHC pattern Supported; BRD4 has no transmembrane segment (UniProt O60885).
| Strong nuclear staining in adipocytes | Expected pattern (HPA: High in adipocytes; UniProt: nucleus). |
| Cytoplasmic-only or membrane-only staining | Discordant with BRD4 localization; assess artefact (UniProt: nucleus; no transmembrane segment). |
| Strong signal restricted to an unexpected cell type | Consider cross-reactivity or endogenous detection activity (general IHC practice). |
| Diffuse staining across the section | May reflect nonspecific background; check controls (general IHC practice). |
| No nuclear signal in adipocytes | Unexpected in this positive tissue; check the assay (HPA: High in adipocytes). |
💡Expected BRD4 appearanceExpect high nuclear adipocyte signal (HPA: High); cytoplasmic-only signal is suspect (UniProt: nucleus).
| What should IF/ICC show? | Mainly nucleoplasm, with mitotic chromosomes also stained (HPA: ICC-IF). |
| Cell-cycle localization | BRD4 associates with acetylated chromatin and mitotic chromosomes (UniProt O60885). |
| Isoforms | BRD4 has three isoforms; check which regions the antibody recognizes (UniProt: A, C, B). |
| HPA antibody validation | IHC is Supported for HPA015055, HPA061646, CAB068177 and CAB068178 (HPA antibodies). |
| Situation | Likely cause | Next action |
|---|---|---|
| No signal in adipocyte nuclei | Assay failure is possible (HPA: High in adipocytes). | Check retrieval, detection and a positive control (general IHC practice). |
| Cytoplasmic-only signal | Localization conflicts with nuclear BRD4 (UniProt O60885). | Review cell morphology and antibody specificity (general IHC practice). |
| Signal in an unexpected cell type | Cross-reactivity or endogenous activity is possible (general IHC practice). | Run a no-primary control and compare the HPA cell pattern (general IHC practice; HPA tissue). |
| Diffuse background | Nonspecific binding or inadequate blocking is possible (general IHC practice). | Optimize blocking, washes and antibody dilution (general IHC practice). |
| Uneven nuclear staining | Uneven retrieval or detection is possible (general IHC practice). | Check section coverage and retrieval consistency (general IHC practice). |
Experiment evidence
IHC & IF images showing BRD4 staining
M00123 · IHCImmunohistochemical analysis of paraffin-embedded human kidney, using Brd4 Antibody.
M00123 · IFImmunofluorescent analysis of Hela cells, using Brd4 Antibody .
A00123-2 · IFIF analysis of BRD4 using anti-BRD4 antibody (A00123-2). BRD4 was detected in an immunocytochemical section of PC-3 cells. Enzyme antigen re
A00123-3 · IFIF analysis of BRD4 using anti-BRD4 antibody (A00123-3). BRD4 was detected in an immunocytochemical section of MCF-7 cells. Enzyme antigen r
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000141867-BRD4/tissue/cerebral+cortex#imid_18795034
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000141867-BRD4/tissue/colon#imid_18794944
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000141867-BRD4/tissue/liver#imid_18794945
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000141867-BRD4/tissue/kidney#imid_18794946
HPA · ICC-IF U-251MGHuman Protein Atlas immunofluorescence, U-251MG, antibody HPA015055; green = BRD4, blue = nucleus, red = microtubules.
HPA · ICC-IF U-251MGHuman Protein Atlas immunofluorescence, U-251MG, antibody HPA015055; green = BRD4, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for BRD4 IHC & IF
🧪Run bone marrow first: hematopoietic cells should show nuclear BRD4 staining (HPA: High in bone-marrow hematopoietic cells; UniProt O60885: nucleus). HPA detects BRD4 in all 45 scored tissues, so there is no validated negative tissue; use no-primary and isotype controls, and expect mature erythrocytes on the positive slide to lack nuclear staining because they are anucleate (HPA: no negative tissue rows; standard histology).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: None in HPA: BRD4 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 BRD4 in U-251MG, U2OS, MCF-7, PC-3, KOLF2.1J, with annotated localisation: Nucleoplasm (enhanced) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and an isotype control matched to the primary antibody’s host species and clonality; assess specificity with BRD4-knockout cell-pellet sections or immunizing-peptide competition when available (standard IHC controls). For bone marrow, block endogenous peroxidase before chromogenic detection because blood cells can produce background (standard IHC practice).
⚠️Feasibility: A BRD4-specific fixation window and antigen-retrieval requirement are unreported in the supplied evidence; optimize retrieval empirically for paraffin IHC (supplied record and M00123 caption: no fixation window or retrieval conditions). The M00123 paraffin-section kidney caption leaves the fixative unreported and does not establish fixation (M00123 tissue-IHC caption). The supplied evidence does not establish whether frozen sections or IF are easier; ICC-IF images show mainly nucleoplasmic BRD4, while endogenous heme peroxidase in bone marrow can complicate chromogenic interpretation (HPA: subcellular ICC-IF; standard IHC practice). The selected M00123 tissue-IHC caption documents paraffin sections, but does not specify the fixative (selected-SKU IHC image M00123).
HPA tissue IHC evidence for BRD4
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 |
|---|---|---|---|---|
| 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 | Adipocytes | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: BRD4 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced BRD4 IHC Tips
Troubleshoot BRD4 staining by checking retrieval, nuclear localisation, antibody epitope coverage and matched controls before comparing signal across paraffin sections.
How should I troubleshoot weak nuclear BRD4 staining after antigen retrieval?
Use Tris-EDTA pH 9.0 heat-induced antigen retrieval at 95–98 °C for 20 min (page retrieval rule: nuclear antigen). BRD4 is a nuclear chromatin-associated protein, so assess staining in intact nuclei before changing retrieval conditions (UniProt O60885 localisation). If nuclei remain weak, compare a longer and a shorter heating interval on adjacent sections while keeping antibody dilution and detection constant (general IHC practice). Include a section processed without primary antibody to distinguish retrieval-associated background from specific nuclear signal (general IHC practice). Record tissue loss and nuclear morphology alongside staining intensity, because harsher retrieval can compromise section integrity (general IHC practice).
Could fixation explain weak or uneven BRD4 staining in paraffin sections?
BRD4-specific fixation sensitivity is unknown from the supplied evidence; the selected M00123 kidney caption identifies paraffin embedding but does not state a fixative (M00123 tissue-IHC caption). Compare sections with documented fixation histories and process them together through retrieval, antibody incubation and chromogenic detection (general IHC practice). Where possible, select blocks with well-preserved nuclei and avoid interpreting fragmented or poorly preserved areas as BRD4 loss (general IHC practice). Keep fixation history separate from the staining result when reporting differences between specimens (general IHC practice). Do not assign a fixation-dependent effect to BRD4 without a controlled comparison using the same antibody and tissue preparation (general IHC practice).
What should I check when BRD4 staining appears cytoplasmic?
Expect predominantly nuclear staining: BRD4 associates with acetylated chromatin, and the HPA describes ubiquitous nuclear expression (UniProt O60885 localisation; HPA tissue IHC). Evaluate intact cells at high magnification and compare chromogen with a nuclear counterstain before calling diffuse cytoplasmic colour positive (general IHC practice). BRD4 can also localise to mitotic chromosomes, so chromosome-associated staining in mitotic cells can fit its reported distribution (HPA subcellular; UniProt O60885 localisation). Check a no-primary control and inspect tissue folds, pigment and precipitate if colour extends beyond nuclei (general IHC practice). BRD4 has no transmembrane segment, so a crisp membrane-only pattern warrants investigation (UniProt O60885 topology).
How can epitope choice affect BRD4 staining across specimens?
BRD4 has 3 reported isoforms, A, B and C; do not assume an antibody detects all three without a mapped epitope and isoform coverage data (UniProt O60885 isoforms; general IHC practice). Its first bromodomain spans residues 58–164, its second spans 348–457, and its NET domain spans 600–682 (UniProt O60885 domains). Check whether the catalog antibody’s immunogen overlaps the sequence present in the isoform under study before interpreting a negative section (general IHC practice). Phosphorylation is reported at several BRD4 residues, including 470 and 484, but an effect on this antibody’s IHC staining has not been established here (UniProt O60885 modified residues; supplied antibody evidence).
How should I investigate BRD4 signal in a multiplex IF experiment?
For multiplex IF, pair BRD4 with an independently validated marker of the expected cell population, such as adipocytes or hematopoietic cells in the corresponding tissues (HPA tissue IHC; general IF practice). Assign BRD4 a spectrally separated fluorophore and compare channels against an unstained tissue section to assess autofluorescence before judging colocalisation (general IF practice). BRD4 is nuclear and has no transmembrane segment, so optimise permeabilisation for access to a nuclear epitope while checking that nuclear morphology remains intact (UniProt O60885 localisation and topology; general IF practice). Use single-label controls to measure bleed-through, and score BRD4 within segmented nuclei rather than from whole-cell fluorescence (general IF practice).
What causes diffuse brown background in BRD4 chromogenic IHC?
First compare the stained section with a no-primary control processed through the same secondary reagent and chromogen steps (general IHC practice). Diffuse colour in both sections points toward detection chemistry or tissue-associated background rather than antibody-dependent BRD4 staining (general IHC practice). Check the peroxidase block when using an HRP–DAB workflow, and inspect endogenous pigment, tissue folds and dried edges before adjusting primary-antibody concentration (general IHC practice). BRD4 is reported mainly in nuclei, so widespread extracellular or lumenal colour does not match its expected localisation (HPA tissue IHC; UniProt O60885 localisation). Titrate the primary antibody only after documenting retrieval and background controls (general IHC practice).
How should I quantify BRD4 staining across paraffin sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define viable, interpretable regions before scoring and use the nuclear counterstain to identify the denominator of evaluable cells (general IHC practice). Report the percentage of BRD4-positive nuclei and, when intensity is reproducible, a nuclear H-score based on the percentages at each intensity level (general IHC practice). For a spatial question, report positive nuclei per mm² of viable tissue and record the analysed area (general IHC practice). Normalise comparisons to the same cell population, section quality, staining run and scoring threshold rather than raw brown area (general IHC practice). BRD4 has broadly reported nuclear expression, so define positivity against appropriate controls rather than assuming an unstained tissue baseline (HPA tissue IHC; general IHC practice).
How can I distinguish true BRD4 staining from artefact?
A credible BRD4 pattern is predominantly nuclear in morphologically intact cells, consistent with its chromatin association and the HPA nuclear profile (UniProt O60885 localisation; HPA tissue IHC). Consider chromosome-associated signal in mitotic cells separately from diffuse cytoplasmic or extracellular deposits (HPA subcellular; general IHC practice). Check whether apparent negatives lie in necrotic areas or poorly preserved tissue, and whether strong positives cluster at section edges or folds (general IHC practice). With HRP–DAB detection, compare a no-primary control and the peroxidase-blocked section to assess endogenous enzyme signal (general IHC practice). Treat cell identity and nuclear morphology as part of the interpretation before assigning biological significance to intensity differences (general IHC practice).
Boster reagents
Best BRD4 / Bromodomain-containing protein 4 IHC Antibodies
The catalog includes anti-BRD4 antibodies with IHC data from paraffin-embedded human kidney and IF/ICC data from human cell lines; all three list Human, Mouse, and Rat reactivity (catalog applications, image captions, and reactivity).
Real IHC data
Anti-Brd4 Rabbit Monoclonal Antibody
Cat # M00123
Real IF data
Anti-BRD4 Antibody ®
Cat # A00123-2
Real IF data
Anti-BRD4 Antibody ®
Cat # A00123-3
M00123 lists IHC and IF/ICC applications and shows IHC staining in paraffin-embedded human kidney (M00123 catalog applications and IHC image caption). A00123-2 shows IF/ICC in PC-3 cells, and A00123-3 shows IF/ICC in MCF-7 cells (respective IF image captions and catalog applications).
Which to pick: Choose M00123 for tissue IHC: it is a rabbit monoclonal antibody with an IHC application and an image from paraffin-embedded human kidney; the caption does not report the fixative (M00123 catalog clone, applications, and IHC image caption). For IF/ICC, A00123-2 has a PC-3 image and A00123-3 has an MCF-7 image; M00123 also lists IF/ICC (respective catalog applications and image captions). All three list Human, Mouse, and Rat reactivity, but the supplied IHC image documents human kidney only (catalog reactivity; M00123 IHC image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O60885 (BRD4_HUMAN, Bromodomain-containing protein 4).
- Human Protein Atlas. BRD4 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. BRD4 subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the mitotic chromosome..
- Human Protein Atlas. BRD4 antibody validation summary (4 antibodies).
- Divergent splicing factor SRSF1 signaling promotes inflammation post-CME: the SRSF1/ENPP3 axis acts via inhibition of BRD4 O-GlcNAcylation to enhance NF-κB activation and accelerate heart failure. Theranostics 2025 — PMC12203807.
- Tumoral BRD4 expression in lymph node-negative breast cancer: association with T-bet+ tumor-infiltrating lymphocytes and disease-free survival. BMC cancer 2018 — PMC6053709.
- Validation of Bromodomain and Extraterminal proteins as therapeutic targets in neurofibromatosis type 2. Neuro-oncology advances 2022 — PMC9278623.
- Bromodomain protein 4 is a novel predictor of survival for gastric carcinoma. Oncotarget 2017 — PMC5458191.
- PubMed PMID:11733348 — UniProt-cited evidence.
- PubMed PMID:15057824 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for BRD4 (Bromodomain-containing protein 4). Expected localisation Ubiquitous nuclear staining (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, 95–98 °C, 20 min (rule: nuclear antigen). Validated IHC antibody: M00123 at 1:50 (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 workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human kidney tissue; fixative not specified (datasheet M00123); 2. Fixation: Image fixative and duration unreported (datasheet M00123); 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 Tris-EDTA buffer, pH 9.0 , 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 monoclonal (clone DBH-2) anti-BRD4, 1:50 (datasheet M00123); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Histone deacetylation can release BRD4 from chromatin (UniProt); Isoform / epitope: 3 isoforms (A, B, C); verify epitope coverage (UniProt); Regulation: Deacetylation reduces chromatin binding (UniProt). Evidence: UniProt O60885, HPA tissue IHC · Supported, HPA ICC-IF · Mainly localized to the nucleoplasm. In addition localized to the…, Datasheet M00123, PMC12203807, PMC6053709. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/BRD4/immunohistochemistry-ihc-guide.