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MAML3 / Mastermind-like protein 3 · IHC design guide
Design Immunohistochemistry for MAML3
Plan MAML3 chromogenic IHC in paraffin sections using the catalog antibody’s documented conditions. Compare cytoplasmic and nuclear staining with HPA tissue observations, while treating nuclear speckles as a molecular expectation from UniProt.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
MAML3 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 nuclear staining observed (HPA tissue IHC) | |
| Staining pattern | High in adipocytes; overall cytoplasmic/nuclear staining (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A07975-1) | |
| Positive control | Adipose tissue+4 more · see all | |
| Negative control | None in HPA (detected in all 44 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation conditions consistent across samples. (standard IHC practice; not target-specific) | |
| Caveat | Staining has medium consistency with RNA expression (HPA tissue IHC) | |
| Regulation | Expression regulation not annotated (UniProt) | |
| Isoform / epitope | No isoforms or processing variants annotated (UniProt) |
Section 1
Recommended MAML3 IHC & IF Protocols
The catalog antibody protocol and two published MAML3 IHC protocols provide starting conditions for paraffin sections (datasheet A07975-1; PMC12398435; PMC8419063).
| Sample | Paraffin-embedded human bladder cancer tissue; fixative not specified (datasheet A07975-1) |
| Fixation | Image fixative and duration unreported (datasheet A07975-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A07975-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A07975-1) |
| Primary antibody | Rabbit anti-MAML3, 2-5 μg/ml (datasheet A07975-1) |
| Primary incubation | Overnight at 4 °C (datasheet A07975-1) |
| Detection | HRP-conjugated secondary, DAB chromogen (datasheet A07975-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | MAML3-positive staining in adipocytes of adipose tissue (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic and nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 (datasheet A07975-1); tris-EDTA boiling for 15 min is a published alternative (PMC12398435).
Section 2
What Is the Expected MAML3 Staining Pattern?
MAML3 is a nuclear transcriptional coactivator with punctate localization in nuclear speckles (UniProt Q96JK9; HPA: nuclear speckles supported). In paraffin section IHC, look for staining in the cell populations HPA reports as high, including adipocytes, hematopoietic cells, endothelial cells, and selected glandular and squamous epithelial cells (HPA: tissue IHC). HPA also describes general cytoplasmic and nuclear expression; its IHC reliability is Approved, with medium consistency against RNA data (HPA: tissue IHC). MAML3 has no transmembrane segment (UniProt Q96JK9 topology).
| Punctate nuclear staining in an HPA high cell population. | This fits MAML3 localization to nuclear speckles (UniProt Q96JK9; HPA: nuclear speckles supported). High staining is reported in adipocytes in adipose tissue and breast, hematopoietic cells in bone marrow, and endothelial cells in colon (HPA: tissue IHC). Judge the identified cell population and compartment together; a dark region alone does not establish a positive result (General IHC interpretation). |
| Predominant membrane or extracellular staining, without a convincing nuclear component. | That pattern is inconsistent with the annotated nuclear localization and absence of a transmembrane segment (UniProt Q96JK9). Treat it as suspect and compare an adjacent section stained without primary antibody (General IHC practice). Cytoplasmic staining alone needs care: HPA describes general cytoplasmic and nuclear expression, so cytoplasm is not automatically an artefact (HPA: tissue IHC). |
| Strong staining in a cell population reported as low by HPA. | Compare cell identity and staining distribution before calling it MAML3. HPA reports low staining in caudate glial cells, parathyroid glandular cells, soft tissue fibroblasts, and spleen red pulp cells (HPA: tissue IHC). An unexpected strong result warrants checks for antibody cross-reactivity or endogenous detection activity (General IHC practice); low does not mean absent. |
| Diffuse color across tissue, including spaces or many unrelated structures. | A widespread deposit that obscures cell borders and nuclei is difficult to score as specific IHC staining (General IHC interpretation). Compare the no-primary control and inspect blocking, washing, and detection steps for background (General IHC practice). Do not use diffuse color as evidence for MAML3 nuclear speckles, which are the supported subcellular location (HPA: subcellular ICC-IF). |
| No discernible signal in a section containing HPA high cells. | First confirm that the expected cells are present: duodenal and gallbladder glandular cells and esophageal and oral mucosal squamous cells are reported high (HPA: tissue IHC). A blank result may reflect an assay failure or sample variation (General IHC interpretation). HPA rates the IHC pattern Approved but notes medium consistency with RNA, so one negative section does not settle target absence (HPA: tissue IHC). |
💡Expected MAML3 appearanceCall a result positive when identifiable HPA high cells show clear nuclear staining, ideally punctate, with cytoplasmic staining interpreted alongside that nuclear pattern (UniProt Q96JK9; HPA: tissue IHC and nuclear speckles supported); broad extracellular or membrane dominant color is suspect rather than the expected MAML3 pattern (UniProt Q96JK9 topology; General IHC interpretation).
| Cell population and tissue context | HPA reports high IHC staining in specific cells within adipose tissue, bone marrow, breast, colon, duodenum, esophagus, gallbladder, and oral mucosa, while RNA has low tissue specificity (HPA: tissue IHC). Select a control by its reported cell population, then verify that those cells are present in the section (General IHC practice). The supplied HPA list contains no designated negative tissue (HPA: tissue IHC). |
| Subcellular evidence and antibody validation | UniProt places MAML3 in the nucleus in a punctate manner, and HPA supports nuclear speckles by ICC-IF (UniProt Q96JK9; HPA: subcellular ICC-IF). HPA calls antibody HPA037717 IHC Approved and ICC Supported; the supplied record does not assign IHC Enhanced status (HPA: antibody validation). Interpret mixed cytoplasmic and nuclear tissue staining within that stated evidence limit (HPA: tissue IHC). |
| IF/ICC Q: What should a positive cell look like? | A: Expect nuclear speckles, supported by HPA ICC-IF and consistent with UniProt's punctate nuclear annotation (HPA: subcellular ICC-IF; UniProt Q96JK9). HPA lists ICC-IF images from A-431, U-251MG, and U2OS and marks HPA037717 ICC Supported (HPA: subcellular ICC-IF; HPA: antibody validation). This is a localization answer, not an IHC protocol recommendation. |
| Situation | Likely cause | Next action |
|---|---|---|
| Nuclear signal is weak in an HPA high cell population. | The expected cells may be sparse, or IHC detection may be underperforming (General IHC interpretation). HPA high denotes an observed staining level in named cells, not guaranteed intensity in every section (HPA: tissue IHC). | Confirm cell identity and section quality; then review the catalog antibody's IHC-P instructions for retrieval and detection and check a concurrently processed control (General IHC practice). Do not infer MAML3 specific fixation sensitivity from these records. |
| Predominant membrane staining appears. | A membrane dominant pattern conflicts with nuclear speckles and no transmembrane segment (HPA: subcellular ICC-IF; UniProt Q96JK9 topology). | Compare the no-primary control and inspect the chromogenic deposit for nonspecific edge or tissue staining (General IHC practice). Report membrane only staining as unconfirmed until a nuclear pattern can be reproduced (General IHC interpretation). |
| Strong color appears in HPA low cells. | Cross-reactivity or endogenous detection activity may contribute (General IHC practice). HPA reports low staining in caudate glial cells, parathyroid glandular cells, soft tissue fibroblasts, and spleen red pulp cells (HPA: tissue IHC). | Verify cell identity, run a no-primary control, and assess the detection system's endogenous activity controls (General IHC practice). Treat HPA low as a comparison point, not proof that any staining is false. |
| Cytoplasmic color dominates a candidate positive cell. | HPA describes general cytoplasmic and nuclear tissue expression, whereas its supported ICC-IF location is nuclear speckles (HPA: tissue IHC; HPA: subcellular ICC-IF). | Score nuclear and cytoplasmic compartments separately and check whether identifiable positive cells retain nuclear staining (General IHC interpretation). Avoid calling cytoplasm alone definitive without additional validation. |
| Color is diffuse across the section. | Broad background may arise from blocking, washing, or detection conditions (General IHC practice); it cannot resolve the supported speckled nuclear location (HPA: subcellular ICC-IF). | Compare no-primary and tissue controls, then review blocking, wash steps, and detection timing under the chosen IHC-P workflow (General IHC practice). Reassess cell specific staining only after background is controlled. |
| A control section shows no staining anywhere. | The control may lack the named HPA high cells, or an assay step may have failed (HPA: tissue IHC; General IHC practice). HPA supplies no designated negative tissue in this record (HPA: tissue IHC). | Check morphology for the expected cell population, confirm that the antibody and detection steps ran, and repeat with a documented HPA high cell population (General IHC practice; HPA: tissue IHC). Record a blank result as inconclusive until the control works. |
Experiment evidence
IHC & IF images showing MAML3 staining
A07975-1 · IHCIHC analysis of MAML3 using anti-MAML3 antibody (A07975-1). MAML3 was detected in a paraffin-embedded section of human bladder cancer tissue
A07975-1 · IHCIHC analysis of MAML3 using anti-MAML3 antibody (A07975-1). MAML3 was detected in a paraffin-embedded section of human breast cancer tissue.
A07975-1 · IFIF analysis of MAML3 using anti-MAML3 antibody (A07975-1) and anti-Beta Tubulin antibody (M01857-3). MAML3 was detected in an immunocytochem
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000196782-MAML3/tissue/cerebral+cortex#imid_9770844
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000196782-MAML3/tissue/colon#imid_9802746
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000196782-MAML3/tissue/liver#imid_9802747
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000196782-MAML3/tissue/kidney#imid_9802748
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA037717; green = MAML3, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA037717; green = MAML3, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for MAML3 IHC & IF
🧪Run adipose tissue first and score adipocytes for MAML3 staining (HPA: High in adipocytes). HPA detects MAML3 in all 44 scored tissues, so use no-primary and isotype controls in place of a negative tissue; cells on the positive slide without punctate nuclear staining can serve as background references, but should not be assumed to lack MAML3 (HPA: no negative tissue; HPA: nuclear speckles).
Positive control tissue: Adipose tissue (Adipocytes, HPA High)
Negative control tissue: None in HPA: MAML3 is detected in all 44 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 MAML3 in A-431, U-251MG, U2OS, with annotated localisation: Nuclear speckles (supported) (HPA subcellular).
Technical controls: Include a secondary-only slide with primary antibody omitted, a concentration-matched rabbit IgG isotype control, and MAML3-knockout material as a biological specificity control (caption: rabbit primary antibody; standard IHC practice). Quench endogenous peroxidase before HRP/DAB detection in the adipose section (caption: HRP/DAB detection; standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected paraffin-section caption does not state a fixative (selected-SKU caption). That example uses heat retrieval in EDTA at pH 8.0, which provides a starting condition without establishing that retrieval is required for every preparation (selected-SKU caption). HPA has ICC-IF images in A-431, U-251MG, and U2OS, but the supplied evidence does not establish whether IF or frozen sections are easier; in adipose sections, assess the compressed peripheral nuclei carefully when scoring adipocytes (HPA: ICC-IF cell lines; standard histology practice).
HPA tissue IHC evidence for MAML3
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 |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Adipocytes | High | Protein (IHC) | HPA → |
| Colon | Endothelial cells | High | Protein (IHC) | HPA → |
| Duodenum | Glandular cells | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: MAML3 is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced MAML3 IHC Tips
Troubleshoot chromogenic MAML3 IHC in paraffin sections using the catalog antibody’s tissue example and the reported nuclear speckle localisation (datasheet A07975-1; UniProt Q96JK9).
Which retrieval conditions should I try first when MAML3 staining is weak?
Start with heat-mediated retrieval in EDTA buffer at pH 8.0 for paraffin-section MAML3 IHC (datasheet A07975-1). Keep retrieval conditions consistent while titrating the primary antibody, because the documented tissue example used 2 μg/ml overnight at 4°C after that retrieval step (datasheet A07975-1). If staining remains weak, compare a second retrieval condition on adjacent sections as a fallback and judge both signal and tissue preservation (standard IHC practice). Include a known staining tissue such as the documented human bladder cancer section, and assess nuclear signal against the expected punctate localisation rather than total brown staining alone (datasheet A07975-1; UniProt Q96JK9).
Could fixation explain weak or uneven MAML3 staining in my paraffin sections?
Target-specific MAML3 sensitivity to fixation is unknown from the supplied evidence; the paraffin-section caption does not state its fixative (datasheet A07975-1). Record the actual fixative and fixation duration for each specimen, then compare sections processed together before assigning weak staining to MAML3 biology (standard IHC practice). Apply the documented EDTA pH 8.0 retrieval and, for an initial comparison, the documented 2 μg/ml primary antibody incubation overnight at 4°C (datasheet A07975-1). If staining varies with processing history, repeat on comparably processed sections and inspect morphology; neither tissue staining patterns nor the protein’s annotated features establish a target-specific fixation effect (standard IHC practice; HPA: tissue IHC; UniProt Q96JK9).
How should I assess MAML3 staining when nuclei and cytoplasm both appear positive?
Prioritise a punctate nuclear pattern when evaluating MAML3, which is reported at nuclear speckles (UniProt Q96JK9; HPA: supported nuclear speckles). The tissue IHC profile also reports general nuclear and cytoplasmic expression, so document both compartments separately rather than treating every cytoplasmic signal as an artefact (HPA: tissue IHC). Compare the same cell types across sections stained with the documented 2 μg/ml antibody condition and a negative control, paying attention to whether nuclear detail survives counterstaining (datasheet A07975-1; standard IHC practice). If diffuse cytoplasmic colour dominates without interpretable nuclei, reassess background, retrieval and detection before drawing a localisation conclusion (standard IHC practice).
What can I infer about epitope accessibility or MAML3 isoforms from this staining?
The supplied record annotates 0 isoforms and no domain boundaries, so it does not establish which MAML3 variants or regions this antibody distinguishes (UniProt Q96JK9). MAML3 is a 1–1138 amino acid chain with no annotated transmembrane segment, while an acetylated lysine is reported at position 603; none of these annotations identifies the antibody epitope (UniProt Q96JK9). If staining differs between specimens, first hold the documented EDTA pH 8.0 retrieval constant and compare processing and controls (datasheet A07975-1; standard IHC practice). Avoid attributing a staining difference to isoform choice or acetylation without epitope information or an independent validation experiment (standard IHC practice).
How can I check MAML3 localisation by IF alongside the chromogenic IHC result?
For a separate IF experiment, include a marker for the cell population being assessed, such as an adipocyte marker in adipose tissue, and inspect MAML3 within those cells (HPA: high staining in adipocytes; standard IF practice). Select fluorophores after checking tissue autofluorescence in each channel, and use distinct channels for the cell marker and MAML3 (standard IF practice). Permeabilise to permit access to the nuclear epitope, because MAML3 is reported at nuclear speckles and has no annotated transmembrane segment (UniProt Q96JK9; standard IF practice). Optimise IF fixation and antibody conditions independently: the 2 μg/ml, overnight paraffin-section example supplies IHC conditions, not an IF fixation result or IF dilution (datasheet A07975-1).
What should I adjust when DAB background obscures MAML3 nuclear staining?
The documented paraffin-section workflow used 10% goat serum blocking, 2 μg/ml primary antibody overnight at 4°C, and DAB chromogen (datasheet A07975-1). Check a no-primary control, block endogenous peroxidase, and review secondary-only staining before interpreting diffuse brown colour as MAML3 (standard IHC practice). If background persists, titrate primary antibody around the documented condition, adjust blocking and washing, and keep DAB development comparable between sections (datasheet A07975-1; standard IHC practice). Evaluate whether remaining signal resolves into identifiable cells and punctate nuclei, while recording cytoplasmic staining separately because the tissue IHC profile reports both compartments (UniProt Q96JK9; HPA: tissue IHC).
How should I quantify MAML3 staining across differently composed tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring; MAML3 has supported nuclear-speckle localisation, while tissue IHC reports nuclear and cytoplasmic staining (HPA: subcellular; HPA: tissue IHC). For chromogenic sections, record the percentage of positive cells and nuclear intensity on a 0–3 scale, then calculate an H-score on a 0–300 scale if intensity is reproducible (standard IHC practice). Alternatively, report positive-cell density per mm² of viable tissue, with the counted area and exclusion rules stated (standard IHC practice). Normalise comparisons to the same cell type, viable area and staining run, since mixed cell populations can change a section-wide average (standard IHC practice).
How can I distinguish a credible MAML3 result from section artefacts?
A credible result should identify stained cells and assess their nuclear pattern against MAML3’s reported punctate nuclear localisation (UniProt Q96JK9; HPA: supported nuclear speckles). Use the expected cell population as context: HPA reports high staining in adipocytes in adipose tissue and endothelial cells in colon, but rates its tissue IHC evidence Approved with medium RNA-staining consistency (HPA: tissue IHC). Treat colour confined to section edges, necrotic areas, or no-primary controls as a reason to investigate processing or endogenous enzyme activity (standard IHC practice). Compare matched sections processed with the documented EDTA pH 8.0 retrieval before interpreting an unusual compartment or cell distribution as a biological change (datasheet A07975-1; standard IHC practice).
Boster reagents
Best MAML3 / Mastermind-like protein 3 IHC Antibodies
The catalog antibody has IHC images from human paraffin sections of bladder and breast cancer and IF images from those tissues and A549 cells (catalog image captions).
Real IHC data
Anti-MAML3 Antibody ®
Cat # A07975-1
A07975-1 is listed for human IHC and illustrated on paraffin sections of bladder and breast cancer (catalog: applications and reactivity; A07975-1 IHC captions). The same SKU is listed for IF/ICC, with images from A549 cells and paraffin sections of bladder and breast cancer (catalog: applications; A07975-1 IF captions).
Which to pick: Choose A07975-1 for human paraffin-section IHC; its own captions show staining in bladder and breast cancer tissue at 2 μg/ml after EDTA retrieval (A07975-1 IHC captions). For IF/ICC, the same rabbit antibody has images from A549 cells and human paraffin sections at 5 μg/ml (catalog: host and applications; A07975-1 IF captions). No cross-species option is listed because A07975-1 is specified for human reactivity only; its paraffin-section IHC captions do not report the fixative (catalog: reactivity; A07975-1 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q96JK9 (MAML3_HUMAN, Mastermind-like protein 3).
- Human Protein Atlas. MAML3 tissue IHC expression (reliability: Approved).
- Human Protein Atlas. MAML3 subcellular location (ICC-IF): Localized to the nuclear speckles..
- Human Protein Atlas. MAML3 antibody validation summary (1 antibodies).
- Prognostic markers in pheochromocytomas/paragangliomas: the role of histopathology, SDHB, MAML3 and MCM6 expression. Journal of endocrinological investigation 2025 — PMC12398435.
- Mastermind Like Transcriptional Coactivator 3 (MAML3) Drives Neuroendocrine Tumor Progression. Molecular cancer research : MCR 2021 — PMC8419063.
- SOX17 is a tumor suppressor in endometrial cancer. Oncotarget 2016 — PMC5342796.
- Biphenotypic sinonasal sarcoma: an expanded immunoprofile including consistent nuclear β-catenin positivity and absence of SOX10 expression. Human pathology 2016 — PMC4981530.
- PubMed PMID:11347906 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15815621 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for MAML3 (Mastermind-like protein 3). Expected localisation Cytoplasmic and nuclear staining observed (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A07975-1). Validated IHC antibody: A07975-1 at 2-5 μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Adipose tissue (Adipocytes); negative None in HPA (detected in all 44 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human bladder cancer tissue; fixative not specified (datasheet A07975-1); 2. Fixation: Image fixative and duration unreported (datasheet A07975-1); 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: EDTA pH 8.0 (datasheet A07975-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A07975-1); 8. Primary antibody: Rabbit anti-MAML3, 2-5 μg/ml (datasheet A07975-1); 9. Primary incubation: Overnight at 4 °C (datasheet A07975-1). Watch for: Fixation: Keep fixation conditions consistent across samples. (standard IHC practice; not target-specific); Caveat: Staining has medium consistency with RNA expression (HPA tissue IHC); Isoform / epitope: No isoforms or processing variants annotated (UniProt); Regulation: Expression regulation not annotated (UniProt). Evidence: UniProt Q96JK9, HPA tissue IHC · Approved, HPA ICC-IF · nuclear speckles., Datasheet A07975-1, PMC12398435, PMC8419063. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/MAML3/immunohistochemistry-ihc-guide.