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SOX6 / Transcription factor SOX-6 · IHC design guide
Design Immunohistochemistry for SOX6
Use this guide to plan chromogenic SOX6 IHC in paraffin sections. It covers nuclear staining in several tissues, including testis (HPA tissue IHC), and a human-reactive IHC-P antibody (datasheet A02877-2).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SOX6 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 in several tissues (HPA tissue IHC) | |
| Staining pattern | Nuclear staining in round or early spermatids (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A02877-2) | |
| Positive control | Skin+4 more · see all | |
| Negative control | Adrenal gland+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation consistent across sections (standard IHC practice; not target-specific) | |
| Caveat | Tissue staining has medium agreement with RNA (HPA tissue IHC) | |
| Regulation | High in round or early spermatids (HPA tissue IHC) | |
| Isoform / epitope | Four isoforms; epitope coverage is undetermined (UniProt) |
Section 1
Recommended SOX6 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet A02877-2) with published SOX6 staining workflows for lung tissue (PMC6943225) and embryonic brain sections (PMC3963837).
| Sample | Paraffin-embedded rat testis tissue; fixative not specified (datasheet A02877-2) |
| Fixation | Image fixative and duration unreported (datasheet A02877-2); 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 A02877-2); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A02877-2) |
| Primary antibody | Rabbit anti-SOX6, 2-5μg/ml (datasheet A02877-2) |
| Primary incubation | Overnight at 4 °C (datasheet A02877-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A02877-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | SOX6-positive staining in melanocytes of skin (HPA tissue IHC: Medium). HPA tissue profile: Nuclear expression in several tissues, including testis. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA retrieval at pH 8.0 for the catalog antibody (datasheet A02877-2).
Section 2
What Is the Expected SOX6 Staining Pattern?
SOX6 is a nuclear and cytoplasmic transcription factor with no transmembrane segment (UniProt P35712). In tissue IHC, expect chiefly nuclear staining in selected cells, especially round or early spermatids in testis, with medium staining reported in melanocytes and several other cell populations (HPA tissue IHC). HPA rates the tissue pattern Enhanced, while describing only medium consistency between staining and RNA expression (HPA tissue IHC).
| Distinct nuclear staining in round or early spermatids, strongest among the listed positive cell populations (HPA: High in testis). | This fits the reported tissue pattern. Judge the signal in the named cells rather than treating every cell in testis as an expected positive; the HPA entry identifies a cell population, not uniform staining across the section (HPA tissue IHC). |
| Predominantly membrane staining, or strong staining confined to cytoplasm without a convincing nuclear pattern. | Review this as a possible localisation artefact. SOX6 has no transmembrane segment and is annotated in the nucleus and cytoplasm (UniProt P35712); HPA describes nuclear tissue expression and supported nucleoplasmic localisation by ICC-IF (HPA tissue IHC; HPA subcellular). Cytoplasmic signal alone is therefore insufficient to call the expected tissue pattern. |
| Strong signal in a cell population reported as undetected, such as adrenal gland glandular cells (HPA: Not detected). | Check the cell identity and detection controls before assigning SOX6 positivity. Cross-reactivity or endogenous detection activity can mimic chromogenic staining (general IHC practice). An HPA negative designation is specific to the listed cell population and does not establish that every cell in that tissue must be blank (HPA tissue IHC). |
| Diffuse colour over cells and surrounding tissue, with nuclei difficult to distinguish. | Treat this as background until a cell-restricted nuclear pattern emerges. Review blocking, washing, chromogen development and the no-primary control (general IHC practice). Diffuse colour does not reproduce the nuclear pattern reported across several tissues (HPA tissue IHC). |
| No nuclear signal in round or early spermatids in an otherwise assessable testis section (HPA: High). | First check that the named cells are present. Then assess the IHC detection run, antibody dilution and antigen retrieval against the applicable antibody instructions (general IHC practice). A failed positive control limits interpretation of negative study sections; the supplied HPA pattern does not identify a SOX6-specific retrieval condition. |
💡Expected SOX6 appearanceA convincing positive is cell-restricted nuclear staining, high in testis round or early spermatids and medium in listed populations such as skin melanocytes (HPA tissue IHC); prominent membrane staining or diffuse colour without nuclear definition is suspect given SOX6 localisation and topology (UniProt P35712; HPA tissue IHC).
| Compartment to score | Score nuclear staining in the specified cell population as the principal tissue readout (HPA tissue IHC). UniProt also annotates cytoplasm, so a cytoplasmic component can be recorded, but it should be interpreted alongside the documented nuclear tissue pattern (UniProt P35712; HPA tissue IHC). |
| Cell population and intensity | Reference levels differ by cell population: round or early spermatids are High; melanocytes, adipocytes, bone marrow hematopoietic cells, cortical neuronal cells and lymph node germinal center cells are Medium (HPA tissue IHC). Compare like cells when assessing intensity. |
| Reference negatives | HPA reports Not detected in specified populations including adrenal gland glandular cells and heart muscle cardiomyocytes (HPA tissue IHC). Use the named cells when checking unexpected staining; a negative entry does not describe every cell in the organ. |
| Strength of validation | HPA labels the tissue pattern Enhanced but notes medium consistency between antibody staining and RNA expression (HPA tissue IHC). Its antibody records distinguish HPA003908 as IHC Enhanced and HPA001923 as IHC Supported (HPA antibodies); do not transfer either rating to a different antibody. |
| IF/ICC question: where should the signal appear? | The supported ICC-IF location is the nucleoplasm (HPA subcellular). That observation helps assess localisation in IF/ICC, but it does not supply an IF/ICC staining protocol or establish performance for the IHC antibody. |
| Situation | Likely cause | Next action |
|---|---|---|
| Testis positive control has no nuclear signal. | The relevant round or early spermatids may be absent from the viewed area, or the detection run may have failed (HPA: High in round or early spermatids; general IHC practice). | Confirm cell identity on the section, then review the antibody instructions, dilution, retrieval and detection controls before interpreting study negatives (general IHC practice). No SOX6-specific retrieval setting is supplied. |
| An HPA reference negative shows strong colour. | The stained cells may differ from the named negative population; cross-reactivity or endogenous detection activity is also possible (HPA tissue IHC; general IHC practice). | Identify the stained cells, examine a no-primary control and check endogenous-activity blocking where applicable (general IHC practice). Compare only with the corresponding HPA cell population. |
| Colour is diffuse and obscures nuclear boundaries. | Background from blocking, washing or chromogen development may obscure a specific pattern (general IHC practice). | Review those workflow steps and the no-primary control; assess SOX6 only when nuclear signal can be distinguished in the expected cells (general IHC practice; HPA tissue IHC). |
| Signal is predominantly at cell membranes. | That distribution conflicts with the reported nuclear tissue pattern and SOX6's lack of a transmembrane segment (HPA tissue IHC; UniProt P35712). | Check morphology and detection controls, and verify the pattern with an independently validated IHC antibody if available (general IHC practice). Do not score membrane colour alone as the expected SOX6 result. |
| A medium-level reference population looks weaker than testis. | HPA reports Medium staining for melanocytes and several other listed populations, compared with High in round or early spermatids (HPA tissue IHC). | Assess each named cell population against its own reference level and retain a working testis control when available (HPA tissue IHC; general IHC practice). Do not require equal intensity across tissues. |
| Two antibodies yield different tissue patterns. | Their HPA IHC validation ratings differ: HPA003908 is Enhanced and HPA001923 is Supported (HPA antibodies). The ratings alone do not identify why individual slides disagree. | Compare staining in the same named positive and negative cell populations, review controls and antibody-specific instructions, and report unresolved differences (HPA tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing SOX6 staining
A02877-2 · IHCIHC analysis of SOX6 using anti-SOX6 antibody (A02877-2). SOX6 was detected in paraffin-embedded section of rat testis tissue. Heat mediated
A02877-2 · IHCIHC analysis of SOX6 using anti-SOX6 antibody (A02877-2). SOX6 was detected in paraffin-embedded section of mouse testis tissue. Heat mediat
A02877 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Tris-EDTA,pH9.0 was used for antigen retrieval. 2 Antibody was diluted at
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000110693-SOX6/tissue/cerebral+cortex#imid_1346276
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000110693-SOX6/tissue/colon#imid_1346210
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000110693-SOX6/tissue/liver#imid_1346211
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000110693-SOX6/tissue/kidney#imid_1346204
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA001923; green = SOX6, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA001923; green = SOX6, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SOX6 IHC & IF
🧪Run testis first and look for SOX6 staining in round or early spermatids (HPA: High in round or early spermatids). Use adrenal gland glandular cells as the negative tissue (HPA: Not detected); on the testis slide, assess other cells for background without assuming they are SOX6-negative.
Positive control tissue: Skin (Melanocytes, HPA Medium)
Negative control tissue: Adrenal gland (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SOX6 in A-431, CACO-2, U2OS, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include no-primary (secondary-only) and host-matched rabbit IgG isotype controls (caption: rabbit primary; standard IHC practice), plus SOX6 knockout material as a biological negative if available (standard IHC practice). Check for endogenous peroxidase and biotin background in testis, particularly with the caption’s biotin-based DAB detection (caption: SABC with DAB; standard IHC practice).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected A02877-2 paraffin-section caption does not state the fixative (caption: fixative unreported). The caption uses heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required (caption: EDTA retrieval). Whether frozen sections or IF are easier is unreported; for chromogenic testis IHC, assess endogenous peroxidase and biotin background (caption: SABC with DAB; standard IHC practice).
HPA tissue IHC evidence for SOX6
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.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Skin | Melanocytes | Medium | Protein (IHC) | HPA → |
| Testis | Round or early spermatids | High | Protein (IHC) | HPA → |
| Adipose tissue | Adipocytes | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Cerebral cortex | Neuronal cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Not detected | Protein (IHC) | HPA → |
| Cervix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Endometrium | Cells in endometrial stroma | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced SOX6 IHC Tips
Troubleshoot SOX6 staining in paraffin sections by checking retrieval, nuclear localisation, cell type and controls before interpreting chromogenic signal.
How should I retrieve SOX6 antigen when nuclear staining is weak?
Start with heat-mediated antigen retrieval in EDTA pH 8.0 for paraffin-section SOX6 IHC (datasheet A02877-2). The selected rat testis image used this retrieval before 2 µg/mL primary antibody overnight at 4°C and DAB detection (caption A02877-2). If staining is weak, check deparaffinisation, heating and cooling consistency on a known positive section; round or early spermatids in testis provide an expected nuclear signal (standard IHC practice; HPA: high in testis round or early spermatids). Compare retrieval duration on serial sections while holding the buffer constant, and inspect a no-primary control for background (standard IHC practice). Consider another buffer only if those checks fail, and validate it against the established EDTA pH 8.0 condition (datasheet A02877-2; standard IHC practice).
Could fixation explain absent SOX6 staining in my paraffin sections?
SOX6-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative (caption A02877-2). Record each specimen’s fixative and fixation duration, then compare similarly processed positive and negative sections before attributing a loss of signal to fixation (standard IHC practice). If processing histories differ, repeat staining together with EDTA pH 8.0 retrieval and the same detection run to reduce technical variation (datasheet A02877-2; standard IHC practice). Inspect tissue preservation and nuclear morphology alongside DAB signal, since damaged sections make cell-level interpretation unreliable (standard IHC practice). Neither the reported tissue distribution nor SOX6’s cellular location establishes a target-specific fixation effect (HPA: tissue IHC profile; UniProt P35712: nucleus and cytoplasm).
Where should convincing SOX6 staining appear in IHC?
Prioritise nuclear staining when assessing SOX6 in paraffin sections: tissue IHC reports nuclear expression, and subcellular IF supports nucleoplasmic localisation (HPA: tissue IHC profile; HPA: nucleoplasm supported). The selected testis section provides a practical cell-level reference because round or early spermatids show high expression in the tissue profile (caption A02877-2; HPA: high in testis round or early spermatids). UniProt also lists cytoplasmic localisation, so a cytoplasmic signal warrants comparison with nuclear staining and controls rather than automatic rejection (UniProt P35712: nucleus and cytoplasm; standard IHC practice). Examine serial sections at matched exposure or microscope settings and score nuclear and cytoplasmic staining separately (standard IHC practice). Diffuse DAB outside intact cells or concentrated along section edges should prompt a background check (standard IHC practice).
Can isoforms or epitope accessibility account for inconsistent SOX6 staining?
SOX6 has 4 annotated isoforms, so confirm which sequence region the antibody recognises before comparing specimens or antibodies (UniProt P35712: isoforms 1–4; standard IHC practice). The supplied caption establishes paraffin-section staining with A02877-2 but does not identify its epitope or demonstrate recognition of every isoform (caption A02877-2). UniProt records several modified residues, including phosphorylation at positions 119, 399, 401, 439 and 442; their effect on this antibody’s staining is unreported (UniProt P35712: modified residues; caption A02877-2). If localisation or intensity differs, compare serial sections under identical retrieval and detection conditions, then seek epitope information before proposing an isoform explanation (standard IHC practice). Avoid interpreting a negative section as isoform absence without independent evidence (standard IHC practice).
How can complementary IF clarify an ambiguous SOX6 IHC result?
Use IF as a complementary localisation check when DAB staining is ambiguous, while keeping the paraffin-section IHC result as the primary readout (standard IHC practice). Multiplex SOX6 with a validated marker for the expected cell type, such as round or early spermatids in testis, and include single-stain controls to assess channel overlap (HPA: high in testis round or early spermatids; standard IF practice). Choose a fluorophore away from strong tissue autofluorescence and check an unstained section before assigning faint fluorescence to SOX6 (standard IF practice). SOX6 has no transmembrane segment and its supported location is nucleoplasmic, so permeabilise sufficiently for antibody access to the nuclear interior while preserving morphology (UniProt P35712: topology; HPA: nucleoplasm supported; standard IF practice). Optimise IF fixation and permeabilisation independently; the selected IHC caption reports no fixative (caption A02877-2; standard IF practice).
What should I check when DAB obscures SOX6 nuclei?
First compare a no-primary section with the SOX6-stained section to identify detection-system signal that does not depend on primary antibody (standard IHC practice). The selected workflow uses biotinylated goat anti-rabbit secondary antibody, a streptavidin–biotin complex and DAB, so check endogenous biotin and peroxidase activity when background persists (caption A02877-2; standard IHC practice). Apply a peroxidase block as a general chromogenic IHC step, and assess whether the secondary and detection reagents stain a control section on their own (standard IHC practice). The selected image used 10% goat serum blocking and 2 µg/mL primary antibody overnight at 4°C; use those conditions as the documented starting point (caption A02877-2). If background remains, optimise antibody concentration and washing against retained nuclear signal (standard IHC practice).
How should I quantify heterogeneous SOX6 staining across a section? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and scoring region before examining DAB intensity, because SOX6 expression varies by tissue and cell type (HPA: tissue IHC profile; standard IHC practice). For nuclear SOX6, report the percentage of positive nuclei and, when intensity matters, an H-score from 0–300 using the percentages at 0, 1+, 2+ and 3+ intensity (HPA: nuclear tissue expression; standard IHC practice). Normalise positive-cell counts to the number of eligible nuclei, or report positive nuclei per mm² of viable analysed tissue with the area stated (standard IHC practice). Keep retrieval, DAB development, counterstaining and score thresholds consistent across sections, and exclude folds, tears and necrotic areas by a predefined rule (standard IHC practice). Report nuclear and cytoplasmic scores separately if both are present (UniProt P35712: nucleus and cytoplasm; standard IHC practice).
How can I distinguish genuine SOX6 signal from staining artefact?
A convincing result places staining in intact nuclei of an expected cell population, such as round or early spermatids in testis (HPA: nuclear tissue expression; HPA: high in testis round or early spermatids). Compare those cells with a no-primary section and with a tissue or cell population reported as undetected, while allowing for biological and assay differences (HPA: tissue IHC profile; standard IHC practice). Treat edge-concentrated DAB, signal over necrotic areas and staining present without primary antibody as reasons to investigate artefact (standard IHC practice). Isolated cytoplasmic staining needs further validation: UniProt lists cytoplasm, but HPA supports nucleoplasmic localisation (UniProt P35712: nucleus and cytoplasm; HPA: nucleoplasm supported). The tissue IHC profile has enhanced reliability yet only medium consistency with RNA expression, so interpret a single unexpected pattern cautiously (HPA: reliability description).
Boster reagents
Best SOX6 / Transcription factor SOX-6 IHC Antibodies
Anti-SOX6 IHC images document paraffin sections of rat and mouse testis and human tonsil (catalog IHC captions). IF is listed for A02877, with no IF image supplied (A02877 catalog).
Real IHC data
Anti-SOX6 Antibody ®
Cat # A02877-2
Real IHC data
Anti-Transcription factor SOX-6 SOX6 Antibody
Cat # A02877
A02877-2 has IHC images from paraffin sections of rat and mouse testis; its listed reactivity is human, mouse and rat (A02877-2 IHC captions; catalog reactivity). A02877 has a paraffin-section IHC image from human tonsil, lists IF/ICC, and lists human, monkey, mouse and rat reactivity (A02877 IHC caption; catalog applications and reactivity).
Which to pick: For tissue IHC, choose A02877-2 when its rat or mouse testis examples match your sample, or A02877 for the human tonsil example (respective IHC captions). For IF/ICC or the broadest listed species coverage, choose the polyclonal A02877; IF/ICC is listed, but no IF image is supplied (A02877 catalog applications, dilution data, reactivity and image records). Both IHC captions specify paraffin sections; neither reports the fixative (respective IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P35712 (SOX6_HUMAN, Transcription factor SOX-6).
- Human Protein Atlas. SOX6 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. SOX6 subcellular location (ICC-IF): Localized to the nucleoplasm..
- Human Protein Atlas. SOX6 antibody validation summary (2 antibodies).
- SRY-box Transcription Factor 6 Is Expressed Not Only in the Dorsal but Also in the Ventral Zone of the Neural Tube and Is Highly Expressed in the Notochord and Chordoma. Acta histochemica et cytochemica 2023 — PMC10323198.
- SOX6 suppresses the development of lung adenocarcinoma by regulating expression of p53, p21(CIPI) , cyclin D1 and β-catenin. FEBS open bio 2020 — PMC6943225.
- Regulation of Sox6 by cyclin dependent kinase 5 in brain. PloS one 2014 — PMC3963837.
- MiR-132-3p Regulates the Osteogenic Differentiation of Thoracic Ligamentum Flavum Cells by Inhibiting Multiple Osteogenesis-Related Genes. International journal of molecular sciences 2016 — PMC5000765.
- PubMed PMID:11255018 — UniProt-cited evidence.
- PubMed PMID:11230166 — UniProt-cited evidence.
- PubMed PMID:16554811 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SOX6 (Transcription factor SOX-6). Expected localisation Nuclear staining in several tissues (HPA tissue IHC). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A02877-2). Validated IHC antibody: A02877-2 at 2-5μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Skin (Melanocytes); negative Adrenal gland. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat testis tissue; fixative not specified (datasheet A02877-2); 2. Fixation: Image fixative and duration unreported (datasheet A02877-2); 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 A02877-2); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A02877-2); 8. Primary antibody: Rabbit anti-SOX6, 2-5μg/ml (datasheet A02877-2); 9. Primary incubation: Overnight at 4 °C (datasheet A02877-2). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Tissue staining has medium agreement with RNA (HPA tissue IHC); Isoform / epitope: Four isoforms; epitope coverage is undetermined (UniProt); Regulation: High in round or early spermatids (HPA tissue IHC). Evidence: UniProt P35712, HPA tissue IHC · Enhanced, HPA ICC-IF · nucleoplasm., Datasheet A02877-2, PMC6943225, PMC3963837. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SOX6/immunohistochemistry-ihc-guide.