This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
SYNGR4 / Synaptogyrin-4 · IHC design guide
Design Immunohistochemistry for SYNGR4
Plan chromogenic SYNGR4 IHC-P with testis as a positive tissue and high staining in elongated or late spermatids (HPA tissue IHC). This guide covers fixation consistency, retrieval, controls and antibody titration from 5 μg/mL (datasheet; standard IHC practice).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
SYNGR4 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 seminiferous ducts (HPA tissue IHC) | |
| Staining pattern | High cytoplasmic staining in elongated or late spermatids (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Testis | |
| Negative control | Adipose tissue+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); assess its effects empirically. | |
| Caveat | Antibody staining and RNA show medium consistency (HPA tissue IHC) | |
| Regulation | Expression regulation is unreported (UniProt) | |
| Isoform / epitope | No isoforms; extracellular versus cytoplasmic epitope is unmapped (UniProt) |
Section 1
Recommended SYNGR4 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with one published SYNGR4 staining workflow (PMC11788336).
| Sample | Tissue sections; selected-image fixative not specified (standard IHC workflow) |
| Fixation | Image fixative and duration unreported (datasheet A19415); 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 citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane 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 anti-SYNGR4, 5 μg/mL (datasheet A19415) |
| 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 | SYNGR4-positive staining in elongated or late spermatids of testis (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in seminiferous ducts. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 HIER at 95–98 °C for 20 min (page antigen-retrieval rule). The published microwave step lacks retrieval conditions (PMC11788336).
Section 2
What Is the Expected SYNGR4 Staining Pattern?
SYNGR4 is a four-pass membrane protein (UniProt O95473 topology). In tissue IHC, the expected signal is cytoplasmic staining within seminiferous ducts, strongest in elongated or late spermatids (HPA: testis High; tissue profile). HPA rates the tissue IHC evidence Enhanced, while noting medium consistency between antibody staining and RNA expression (HPA: reliability description). Interpret the observed cytoplasmic pattern as an IHC finding; the membrane annotation alone does not specify a resolvable membrane outline in paraffin sections (UniProt O95473; HPA: tissue profile).
| Strong cytoplasmic signal in elongated or late spermatids within seminiferous ducts. | This matches the reported positive tissue and cell type (HPA: testis High; tissue profile). Check that the signal follows cells and duct architecture rather than appearing uniformly across the section (general IHC practice). HPA's Enhanced rating supports this tissue pattern, subject to its stated medium staining–RNA consistency (HPA: reliability description). |
| Predominantly nuclear signal, or staining confined to an unrelated compartment. | Treat this as a localization mismatch: HPA describes cytoplasmic tissue staining, and UniProt annotates a membrane protein (HPA: tissue profile; UniProt O95473). Review morphology, counterstain, and control sections before calling such staining SYNGR4 (general IHC practice). A punctate or perinuclear appearance alone is insufficient to override the tissue IHC reference pattern. |
| Strong signal in cells other than elongated or late spermatids, especially in a reference-negative tissue. | Question specificity when the staining departs from the reported High testis cell population (HPA: testis High). Adipocytes in adipose tissue and glandular cells in adrenal gland are listed as Not detected (HPA: tissue IHC). Cross-reactivity or residual endogenous detection activity are possible technical explanations; compare controls before assigning either cause (general IHC practice). |
| Diffuse staining across ducts, stroma, or most of the section, with poor cell boundaries. | A widespread haze does not reproduce the cell-restricted cytoplasmic profile (HPA: tissue profile; testis High). It can reflect nonspecific binding, incomplete blocking, or detection background (general IHC practice). Compare a no-primary control and a reference-negative tissue, then assess whether any cell-specific signal remains above the background (general IHC practice). |
| No convincing signal in a testis section containing elongated or late spermatids. | This conflicts with the reported High staining in that cell population (HPA: testis High). First confirm the relevant cells are present on the section; then check control performance, antibody compatibility, and detection steps (general IHC practice). An absent result in one run does not by itself overturn the HPA tissue pattern. |
💡Expected SYNGR4 appearanceCall positive when elongated or late spermatids show conspicuous cytoplasmic staining in seminiferous ducts (HPA: testis High; tissue profile); dominant nuclear signal or similarly strong staining across unrelated cells warrants specificity checks (HPA: tissue profile; general IHC practice).
| Protein topology and apparent compartment | Four transmembrane segments place SYNGR4 in membranes (UniProt O95473 topology); tissue IHC reports cytoplasmic expression (HPA: tissue profile). Score the observed cell-associated pattern without requiring a crisp plasma-membrane rim (general IHC practice). |
| Tissue and cell selection | Testis elongated or late spermatids are High (HPA: tissue IHC). Duodenal, small-intestinal, colonic, and rectal glandular cells and hepatocytes are Low; these are weaker comparison tissues, not equivalent positive controls (HPA: tissue IHC). |
| Reference-negative cells | Adipose adipocytes, adrenal glandular cells, and several other sampled cells are Not detected (HPA: tissue IHC). Use a listed negative cell population to assess background while retaining the cell-level scope of each HPA call (general IHC practice). |
| Antibody evidence | HPA030075 and HPA059286 each have Enhanced IHC status (HPA: antibody validation). This supports the reference pattern, while HPA reports only medium consistency between tissue staining and RNA expression (HPA: reliability description). |
| IF/ICC: what localization is reported? | Golgi apparatus is the approved main ICC-IF location; images are listed for A-549 and HEK293, and HPA059286 has Approved ICC status (HPA: subcellular; antibody validation). This is an IF/ICC reference, not a paraffin IHC localization requirement. |
| Situation | Likely cause | Next action |
|---|---|---|
| Testis positive control is blank despite visible late spermatids. | The expected High cell population is present (HPA: testis High), so the run or reagent chain may have failed (general IHC practice). | Check primary-antibody use, detection reagents, and the run control; review the retrieval conditions used for this assay before repeating (general IHC practice). No SYNGR4-specific retrieval condition is supplied. |
| Signal is weak and difficult to distinguish from counterstain. | The reported testis signal is High (HPA: testis High); weak contrast may reflect staining or imaging conditions (general IHC practice). | Compare the testis control with its no-primary control; check chromogen development and counterstain intensity, then adjust the assay using validated control sections (general IHC practice). |
| Most tissue compartments stain evenly. | Uniform signal does not match cytoplasmic staining in seminiferous ducts (HPA: tissue profile); background from binding or detection is possible (general IHC practice). | Run a no-primary control, review blocking and washes, and compare with a listed Not detected cell population (HPA: tissue IHC; general IHC practice). |
| Reference-negative cells show strong chromogenic staining. | Staining in cells listed as Not detected raises a specificity or endogenous-detection concern (HPA: tissue IHC; general IHC practice). | Compare no-primary and other assay controls; check the detection chemistry's endogenous-activity block where applicable before interpreting the signal as SYNGR4 (general IHC practice). |
| Only nuclei appear positive in the testis section. | Nuclear dominance conflicts with the reported cytoplasmic tissue pattern (HPA: tissue profile) and membrane annotation (UniProt O95473). | Recheck cell identification and counterstain, then compare antibody-stained and no-primary sections for a reproducible cytoplasmic signal (general IHC practice). |
| An IF/ICC Golgi pattern seems different from the IHC slide. | HPA reports approved Golgi localization by ICC-IF and cytoplasmic expression by tissue IHC (HPA: subcellular; tissue profile). | Assess each application against its own reference observation; use cell type and cytoplasmic signal for the paraffin IHC call (HPA: tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing SYNGR4 staining
A19415 · IHCImmunohistochemistry of SYNGR4 in rat brain tissue with SYNGR4 antibody at 5 μg/mL.
A19415 · IFImmunofluorescence of SYNGR4 in rat brain tissue with SYNGR4 antibody at 20 μg/mL.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000105467-SYNGR4/tissue/cerebral+cortex#imid_20202293
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000105467-SYNGR4/tissue/colon#imid_20202203
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000105467-SYNGR4/tissue/liver#imid_20202220
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000105467-SYNGR4/tissue/kidney#imid_20202205
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA059286; green = SYNGR4, blue = nucleus, red = microtubules.
HPA · ICC-IF A-549Human Protein Atlas immunofluorescence, A-549, antibody HPA059286; green = SYNGR4, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for SYNGR4 IHC & IF
🧪Run testis first and score staining in elongated or late spermatids (HPA: High in testis elongated or late spermatids). Use adipose tissue adipocytes as the negative tissue (HPA: Not detected in adipocytes); other cells on the testis slide should lack specific staining relative to the spermatids and serve as an internal comparison (HPA: High in elongated or late spermatids).
Positive control tissue: Testis (Elongated or late spermatids, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show SYNGR4 in A-549, HEK293, with annotated localisation: Golgi apparatus (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control; a host-matched isotype control for a monoclonal antibody or nonimmune IgG control for a polyclonal antibody; and, if available, a SYNGR4 knockout or immunizing-peptide block as a biological specificity control (standard IHC/IF practice). For chromogenic testis IHC, block endogenous peroxidase and assess background on the no-primary slide; for IF, check testis autofluorescence (standard IHC/IF practice).
⚠️Feasibility: The supplied evidence reports neither a SYNGR4-specific fixation window nor its dependence on antigen retrieval, and the exact A19415 tissue-IHC caption does not state a fixative (selected IHC caption: A19415, rat brain). These data do not establish whether frozen sections or IF would be easier than paraffin IHC; ICC-IF images show a Golgi location in A-549 and HEK293 cells, which does not establish a tissue IF result (HPA subcellular: Golgi apparatus; A-549 and HEK293). In testis, check background against the no-primary control before scoring spermatids, since tissue background can obscure specific chromogenic or fluorescent signal (standard IHC/IF practice).
HPA tissue IHC evidence for SYNGR4
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 |
|---|---|---|---|---|
| Testis | Elongated or late spermatids | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Adrenal gland | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Not detected | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Not detected | Protein (IHC) | HPA → |
| Breast | Adipocytes | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced SYNGR4 IHC Tips
Use cell type, compartment and matched controls to troubleshoot SYNGR4 staining in paraffin sections; interpret the rat brain image with its fixation details unresolved.
How should I retrieve SYNGR4 in paraffin sections when staining is weak?
Begin with citrate pH 6.0 heat retrieval at 95–98 °C for 20 min (page retrieval setting). Allow sections to cool in retrieval buffer for about 20 min, then wash and compare them with a known positive testis section processed in the same run (standard IHC practice; HPA: high in elongated or late spermatids). If staining remains weak, compare a longer citrate retrieval with the starting condition on adjacent sections, watching for tissue damage and increased background (standard IHC practice). Record retrieval temperature, time and staining intensity together, because SYNGR4 has 4 transmembrane segments and an unmapped antibody epitope (UniProt O95473 topology; supplied record: no epitope mapping).
Could fixation explain inconsistent SYNGR4 staining between paraffin blocks?
Target-specific fixation sensitivity is unknown: the selected A19415 rat brain IHC caption reports 5 µg/mL antibody but does not state the fixative (selected A19415 tissue-IHC caption). For a controlled comparison, fix matched samples in 10% neutral buffered formalin for a consistent interval, such as 12–24 h, and process them together (standard IHC practice). Keep section thickness, retrieval and detection constant while comparing blocks, and include a positive testis section in each run (standard IHC practice; HPA: high in elongated or late spermatids). Treat any staining difference as a processing association until matched fixation conditions and appropriate controls establish its cause (standard IHC practice).
What staining pattern and cell location should support a SYNGR4 call?
In paraffin IHC, assess intracellular staining in elongated or late spermatids within testis; HPA reports high expression in those cells and cytoplasmic expression in seminiferous ducts (HPA tissue IHC). A compact perinuclear pattern can be compatible with the approved Golgi location, although chromogenic sections may not resolve individual membranes (HPA subcellular: Golgi apparatus; standard IHC practice). SYNGR4 is a membrane protein with 4 transmembrane segments, so diffuse nuclear staining needs independent support before interpretation (UniProt O95473 topology; standard IHC practice). Compare the expected cell population with neighbouring cells on the same slide and with a matched negative-control section (standard IHC practice).
How can an unknown epitope affect SYNGR4 IHC troubleshooting?
The supplied record lists 0 annotated isoforms and gives no antibody epitope, so it cannot establish which side of the membrane the catalog antibody recognizes (supplied UniProt record; supplied antibody evidence). SYNGR4 contains 4 transmembrane segments at residues 25–45, 66–86, 104–124 and 145–165, with a MARVEL domain spanning 18–169 (UniProt O95473 topology and domain). Compare adjacent sections using the same retrieval and a primary-antibody omission control before attributing a changed pattern to epitope exposure (standard IHC practice). If epitope documentation becomes available, check whether the mapped sequence is accessible after fixation and retrieval; do not assign accessibility from topology alone (standard IHC practice; supplied record: epitope unspecified).
How should I investigate SYNGR4 localisation with a companion IF experiment?
Use IF as a companion experiment and multiplex SYNGR4 with an independently validated marker for elongated or late spermatids, the high-expressing testis population reported by HPA (HPA tissue IHC; standard IF practice). Select fluorophores after inspecting unstained tissue autofluorescence, placing the weaker signal in a spectral channel with less background (standard IF practice). HPA reports an approved Golgi location and ICC/IF images in A-549 and HEK293 cells, which provide compartment context rather than paraffin IHC validation (HPA subcellular). Because the antibody epitope's membrane-facing side is unspecified, compare mild permeabilisation with an otherwise matched condition and retain single-stain controls for bleed-through assessment (supplied antibody evidence; standard IF practice).
What should I change when SYNGR4 chromogenic staining is diffuse?
First inspect the primary-antibody omission control and an expected low-signal area, such as adipocytes in adipose tissue, which HPA reports as not detected (standard IHC practice; HPA tissue IHC). Quench endogenous peroxidase before enzyme detection, block nonspecific binding, and use fresh washes between antibody and chromogen steps (standard chromogenic IHC practice). If diffuse colour persists, titrate the primary antibody downward and shorten chromogen development while keeping retrieval and imaging conditions fixed (standard IHC practice). The A19415 rat brain caption documents 5 µg/mL for that image, but gives no fixative and does not establish an optimal concentration for every paraffin block (selected A19415 tissue-IHC caption).
How should I score SYNGR4 staining across testis sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define the elongated or late spermatid compartment before scoring, because HPA reports high SYNGR4 signal there (HPA tissue IHC). For chromogenic IHC, report the percentage of positive cells and an H-score based on intensity categories 0–3, using the same threshold and exposure review across sections (standard IHC scoring practice). Normalise positive-cell counts to the number of eligible spermatids examined, or report positive-cell density per mm² of evaluable seminiferous duct area (standard IHC quantification practice). Exclude folds, torn edges and necrotic regions by predefined rules, and score matched negative-control sections to estimate background (standard IHC practice).
When is a SYNGR4 positive IHC result likely to be artefactual?
A convincing testis result places staining in elongated or late spermatids and is compatible with the cytoplasmic seminiferous-duct profile reported by HPA (HPA tissue IHC). Strong nuclear staining or a pattern confined to tissue edges calls for review, given the membrane topology and approved Golgi localisation (UniProt O95473 topology; HPA subcellular; standard IHC practice). Exclude necrotic areas and check the primary-antibody omission control for endogenous enzyme signal before accepting diffuse chromogen deposition (standard chromogenic IHC practice). The A19415 image shows rat brain staining at 5 µg/mL, but its caption leaves fixation unspecified, so assess any brain result with its own matched controls (selected A19415 tissue-IHC caption; standard IHC practice).
Boster reagents
Best SYNGR4 / Synaptogyrin-4 IHC Antibodies
A19415 has IHC and IF images from rat brain tissue (catalog image captions); its listed reactivity covers human, mouse and rat (catalog: reactivity).
Real IHC data
Anti-Synaptogyrin-4 SYNGR4 Antibody
Cat # A19415
A19415 is listed for IHC-P and IF (catalog: applications). Its IHC and IF images show rat brain tissue at 5 μg/mL and 20 μg/mL, respectively (catalog image captions).
Which to pick: For paraffin-section IHC, choose A19415: IHC-P is listed, and its IHC image shows rat brain tissue at 5 μg/mL (catalog: applications; A19415 IHC image caption); the fixative is unreported (A19415 IHC image caption). For IF, A19415 has a rat brain tissue image at 20 μg/mL (A19415 IF image caption); ICC validation and clonality are unreported (catalog: applications; clone field). For human, mouse or rat samples, A19415 lists reactivity with all three species (catalog: reactivity); the supplied IHC and IF images show rat tissue only (catalog image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry O95473 (SNG4_HUMAN, Synaptogyrin-4).
- Human Protein Atlas. SYNGR4 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. SYNGR4 subcellular location (ICC-IF): Localized to the Golgi apparatus..
- Human Protein Atlas. SYNGR4 antibody validation summary (2 antibodies).
- Unveiling the role of SYNGR4 in breast cancer development: a novel target for immunotherapy. Frontiers in oncology 2024 — PMC11788336.
- Pan-cancer multi-omics analysis identifies SYNGR4 as a novel clinical prognostic biomarker and therapeutic target in lung adenocarcinoma. Discover oncology 2026 — PMC13429564.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for SYNGR4 (Synaptogyrin-4). Expected localisation Cytoplasmic staining in seminiferous ducts (HPA tissue IHC). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A19415 at 5 μg/mL (the product's own IHC validation image is shown). Controls (HPA): positive Testis (Elongated or late spermatids); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Tissue sections; selected-image fixative not specified (standard IHC workflow); 2. Fixation: Image fixative and duration unreported (datasheet A19415); 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 citrate buffer, pH 6.0 , 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 anti-SYNGR4, 5 μg/mL (datasheet A19415); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); assess its effects empirically.; Caveat: Antibody staining and RNA show medium consistency (HPA tissue IHC); Isoform / epitope: No isoforms; extracellular versus cytoplasmic epitope is unmapped (UniProt); Regulation: Expression regulation is unreported (UniProt). Evidence: UniProt O95473, HPA tissue IHC · Enhanced, HPA ICC-IF · Golgi apparatus., Datasheet A19415, PMC11788336. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/SYNGR4/immunohistochemistry-ihc-guide.