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- Table of Contents
Plan chromogenic MCM4 IHC around variable nuclear staining across tissues (HPA tissue IHC). Compare high staining in bone marrow hematopoietic cells with low staining in parathyroid glandular cells (HPA tissue IHC), using the catalog antibody at 2–5 μg/mL (datasheet A02301-1).
Expected localisation, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
| Expected localisation | Nuclear staining in tissue (HPA tissue IHC) | |
| Staining pattern | Variable nuclear staining across all tissues (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02301-1) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | None in HPA (detected in all 45 tissues); use no-primary + isotype controls |
| Fixation | Keep fixation consistent between sections. (standard IHC practice; not target-specific) | |
| Caveat | Chromatin association changes as replication progresses (UniProt) | |
| Regulation | Variable expression across tissues (HPA tissue IHC) | |
| Isoform / epitope | No isoforms annotated; one chain spans 2–863 (UniProt) |
The catalog antibody uses EDTA pH 8.0 heat retrieval (datasheet A02301-1). Three published MCM4 IHC protocols provide tissue-specific settings (PMC10515259; PMC12967608; PMC5250507).
| Sample | Paraffin-embedded mouse colon tissue; fixative not specified (datasheet A02301-1) |
| Fixation | Image fixative and duration unreported (datasheet A02301-1); 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 A02301-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02301-1) |
| Primary antibody | Rabbit anti-MCM4, 2-5μg/ml (datasheet A02301-1) |
| Primary incubation | Overnight at 4 °C (datasheet A02301-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A02301-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | MCM4-positive staining in germinal center cells of appendix (HPA tissue IHC: High). HPA tissue profile: Nuclear expression at variable levels in all tissues. No signal in the no-primary control. |
MCM4 is a nuclear, chromatin-associated replication factor with no transmembrane segment (UniProt P33991: location, function, topology). In paraffin-section IHC, expect nuclear staining at variable levels across tissues, including high staining in bone-marrow hematopoietic cells and appendix germinal-center cells (HPA tissue IHC). HPA rates the tissue pattern Enhanced but reports medium consistency between antibody staining and RNA expression; interpret an individual slide with that qualification (HPA tissue IHC).
| Distinct nuclear staining in bone-marrow hematopoietic cells or appendix germinal-center cells (HPA tissue IHC: High). | This fits the reported compartment and cell types (HPA tissue IHC: nuclear expression, High in these cells). Compare nuclei with the counterstain and assess staining in the expected cells, since HPA reports variable levels across tissues (HPA tissue IHC; general IHC practice). |
| Predominantly cytoplasmic, membranous, or extracellular staining with little nuclear signal (UniProt P33991: nuclear/chromosomal location, no transmembrane segment). | That distribution conflicts with the expected MCM4 pattern (UniProt P33991: location; HPA tissue IHC: nuclear expression). Consider nonspecific staining or detection artefact; compare with an appropriate negative control before scoring it as target signal (general IHC practice). |
| Strong staining dominates smooth-muscle cells or soft-tissue chondrocytes (HPA tissue IHC: Low in these cells). | HPA reports low staining in those cell types, so strong staining there deserves scrutiny; low does not mean absent (HPA tissue IHC). Check tissue identity and control staining, then consider cross-reactivity or endogenous detection activity (general IHC practice). |
| Chromogen spreads across nuclei, cytoplasm, and empty tissue spaces without a clear cellular pattern (general IHC practice). | Diffuse background cannot establish MCM4 localisation (general IHC practice). Inspect the negative control and staining distribution; incomplete blocking, excess antibody, or residual detection activity can produce background in chromogenic IHC (general IHC practice). |
| No nuclear signal in bone marrow or appendix where HPA reports high staining in specified cells (HPA tissue IHC). | First confirm that the relevant hematopoietic or germinal-center cells are present (HPA tissue IHC; general IHC practice). Then review the antibody dilution, retrieval, detection reagents, and positive control as general IHC checks; this observation alone does not establish an MCM4-specific fixation effect (general IHC practice). |
| Cellular compartment and replication context (UniProt P33991: location, function). | MCM4 functions in the MCM2–7 and CMG helicase complexes and associates with chromatin before nuclei form, detaching as DNA replication progresses (UniProt P33991). Score the observed nuclear distribution; do not infer replication phase from stain intensity alone (general IHC practice). |
| Tissue and cell-type variation (HPA tissue IHC). | HPA reports variable nuclear expression across tissues, with high staining in bronchial basal cells and breast glandular cells but low staining in liver cholangiocytes and parathyroid glandular cells (HPA tissue IHC). Choose the comparison cell population explicitly when judging intensity (general IHC practice). |
| Antibody evidence (HPA antibody validation; HPA tissue IHC). | HPA004873 and CAB004497 have Enhanced IHC validation; HPA031052 has no listed IHC validation status (HPA antibody validation). HPA nevertheless describes only medium agreement between staining and RNA data, so Enhanced should not be treated as proof that every positive cell is specific (HPA tissue IHC; general IHC practice). |
| Processing and epitope information (UniProt P33991). | UniProt lists no signal peptide, propeptide, transmembrane segment, or glycosylation site, and lists modified residues including phosphorylation (UniProt P33991). These annotations do not identify this antibody’s epitope or establish a retrieval setting or fixation sensitivity; select and verify those conditions using the antibody instructions and controls (general IHC practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Expected positive cells are present, but their nuclei are unstained (HPA tissue IHC: High in specified bone-marrow and appendix cells). | Possible assay failure or insufficient signal; the slide alone cannot identify which step failed (general IHC practice). | Check the positive control, antibody dilution, retrieval step, and detection reagents, following the IHC-validated antibody’s instructions (general IHC practice). |
| Strong chromogen appears in cells reported as low-staining by HPA (HPA tissue IHC: smooth muscle and chondrocytes Low). | Tissue variation is possible, while cross-reactivity or endogenous detection activity may also contribute (HPA tissue IHC; general IHC practice). | Verify the cell type, examine a negative control, and compare its distribution with the nuclear signal in expected positive cells (general IHC practice; HPA tissue IHC). |
| Cytoplasmic colour is stronger than nuclear colour (UniProt P33991: nuclear/chromosomal location). | The compartment conflicts with the reported MCM4 distribution and may reflect background or nonspecific binding (UniProt P33991; general IHC practice). | Check whether nuclear staining remains distinguishable after reviewing the counterstain and negative control; avoid scoring cytoplasmic colour alone as positive (general IHC practice). |
| Most of the section has diffuse chromogenic haze (general IHC practice). | Background may arise from blocking, antibody concentration, washing, or endogenous detection activity (general IHC practice). | Compare the negative control, then review blocking, dilution, washes, and detection controls under the chosen IHC workflow (general IHC practice). |
| A low-staining reference cell type gives little signal (HPA tissue IHC: Low in parathyroid glandular cells). | Low staining may reflect the reported biological pattern and is a weak basis for declaring assay failure (HPA tissue IHC; general IHC practice). | Judge assay performance against a section containing an expected high cell population, such as bone-marrow hematopoietic cells (HPA tissue IHC; general IHC practice). |
| Q: What localisation should IF/ICC show? (HPA subcellular ICC-IF). | HPA reports the nucleoplasm as MCM4’s main ICC-IF location, with Enhanced localisation evidence (HPA subcellular ICC-IF). | A: Expect nucleoplasmic fluorescence and interpret prominent extranuclear fluorescence cautiously (HPA subcellular ICC-IF; general IF practice). Use the separate IF/ICC guide for assay setup. |
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — 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.
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Appendix | Germinal center cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Glandular cells | High | Protein (IHC) | HPA → |
| Bronchus | Basal cells | High | Protein (IHC) | HPA → |
| Caudate | Glial cells | High | Protein (IHC) | HPA → |
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: MCM4 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Troubleshoot MCM4 chromogenic IHC by checking nuclear staining, tissue preparation, detection background, and scoring against appropriate controls.
Anti-MCM4 antibodies have IHC images from paraffin sections of mouse colon and human colorectal adenocarcinoma, plus IF/ICC data from A431 cells (catalog image captions).
A02301-1 has IHC images from mouse and rat colon, human breast cancer, and human gallbladder adenocarcinoma, plus IF/ICC data from A431 cells (catalog image captions). M02301 has IHC images from human colorectal adenocarcinoma and spleen (catalog image captions).
Which to pick: For human tissue IHC, consider rabbit monoclonal M02301: its paraffin-section image used EDTA retrieval at pH 8.0 and a 1:50 primary dilution (catalog: clone 24M40; M02301 IHC caption). For IF/ICC, choose A02301-1, which lists both applications and has an A431-cell IF image at 5 μg/ml (catalog applications; A02301-1 IF caption). A02301-1 also covers the broadest listed species range for IHC—human, mouse, and rat—with paraffin-section images for each; neither SKU’s IHC caption reports the fixative (catalog reactivity; A02301-1 IHC captions; M02301 IHC captions).