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GJA3 / Gap junction alpha-3 protein · IHC design guide
Design Immunohistochemistry for GJA3
Plan GJA3 paraffin IHC with lens fiber cells as a positive reference (HPA tissue IHC). This guide covers fixation, retrieval, the catalog antibody’s 1:100 IHC dilution (datasheet), and interpretation of expected membrane and gap junction localization (UniProt).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
GJA3 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 | Cell membrane and gap junction expected (UniProt) | |
| Staining pattern | Lens fiber cells stain; subcellular pattern unreported (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen) | |
| Positive control | Eye | |
| 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) | |
| Caveat | Presumed off-target binding may complicate interpretation (HPA tissue IHC) | |
| Regulation | No expression regulation annotated (UniProt) | |
| Isoform / epitope | No isoforms annotated; extracellular vs cytoplasmic epitope side matters (UniProt) |
Section 1
Recommended GJA3 IHC & IF Protocols
The catalog antibody IHC-P protocol is accompanied by 2 published GJA3 IHC protocols (PMC13543546; PMC4453443).
| Sample | Paraffin-embedded human lung carcinoma tissue; fixative not specified (datasheet A30696) |
| Fixation | Image fixative and duration unreported (datasheet A30696); 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-GJA3, 1:100 (datasheet A30696) |
| 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 | GJA3-positive staining in lens fiber cells of eye (HPA tissue IHC: High). HPA tissue profile: Expression in lens. No signal in the no-primary control. |
💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page antigen-retrieval rule); use each article’s conditions when reproducing its protocol (PMC13543546; PMC4453443).
Section 2
What Is the Expected GJA3 Staining Pattern?
GJA3 should localise to cell membranes and gap junctions (UniProt Q9Y6H8: subcellular location; 4 transmembrane segments). In paraffin section IHC, the expected positive cells are lens fiber cells, where HPA reports High staining (HPA: Eye, lens fiber cells). HPA rates its tissue IHC evidence Supported, while noting presumed off target binding was disregarded and internal RNA correlation was unavailable (HPA: reliability description).
| Lens fiber cell borders show distinct chromogenic staining, sometimes as short lines or puncta. | This fits membrane and gap junction localisation (UniProt Q9Y6H8: subcellular location; HPA: subcellular summary, Membrane) in the cell type with High tissue staining (HPA: Eye, lens fiber cells). Judge a positive result by its cell type and border localisation as well as its strength. HPA's High category describes its observed lens staining; it does not guarantee identical intensity in every section or detection run (HPA: tissue IHC). |
| Signal fills nuclei or appears predominantly diffuse within lens fiber cells. | A predominantly nuclear or diffuse cytoplasmic pattern does not match the reported membrane and gap junction location (UniProt Q9Y6H8: subcellular location; HPA: subcellular summary, Membrane). Treat it as suspect until the lens border pattern is visible in a suitable positive control. Check whether the chromogen is confined to cells and whether the counterstain makes the compartment clear (general IHC practice). |
| Strong staining appears in adipocytes, adrenal glandular cells, or other listed negative cells. | HPA reports GJA3 as Not detected in adipocytes and adrenal glandular cells, among its listed negative observations (HPA: tissue IHC). Such signal warrants assessment for off target binding or detection background; HPA itself notes presumed off target binding was observed and disregarded during reliability assessment (HPA: reliability description). A positive mark in a negative tissue alone should not be scored as GJA3 expression. |
| Color spreads across extracellular spaces, section edges, or many cell types without clear borders. | That distribution lacks the cell and compartment specificity expected from lens fiber staining and membrane localisation (HPA: Eye, lens fiber cells; UniProt Q9Y6H8: subcellular location). Review the detection blank and counterstain before interpreting weak deposits. Excess primary or detection reagent, incomplete blocking, or endogenous detection activity can produce broad chromogenic background (general IHC practice). |
| No convincing signal appears in the lens fiber cells of a known positive section. | A blank result conflicts with HPA's High lens fiber observation (HPA: Eye, lens fiber cells), but it does not by itself establish absent GJA3. Check section quality, primary antibody application, retrieval conditions, detection reagents, and the run's positive control (general IHC practice). HPA supplies no target specific fixation sensitivity or retrieval condition here, so attribute a failed run only after those controls are reviewed. |
💡Expected GJA3 appearanceCall positive a distinct lens fiber cell border pattern, potentially punctate at junctions, with readily visible signal consistent with HPA's High lens observation; isolated nuclear staining or broad staining of HPA negative cells is suspect (UniProt Q9Y6H8: gap junction location; HPA: Eye, lens fiber cells; HPA: listed negative tissues).
| Membrane topology and epitope placement | GJA3 has 4 transmembrane segments, extracellular loops, and cytoplasmic regions (UniProt Q9Y6H8: topology). If the antibody's epitope is known, use its location when assessing accessibility; no epitope or GJA3 specific retrieval effect is supplied. |
| Tissue evidence and antibody validation | Lens fiber staining is High, and HPA rates the tissue result Supported (HPA: tissue IHC; HPA: reliability). Its caveat is presumed off target binding and no internal RNA correlation (HPA: reliability description); review unexpected staining against that limit. |
| RNA versus protein readouts | HPA lists tissue enhanced RNA in heart muscle, parathyroid gland, and placenta, while its positive protein IHC observation here is lens fiber cells (HPA: RNA specificity; HPA: tissue IHC). Do not treat RNA enrichment as a predicted positive IHC pattern. |
| IF/ICC evidence | For IF/ICC, what location is supported? HPA gives only a Membrane summary and no cell line ICC/IF images; it lists no ICC status for HPA014821 (HPA: subcellular summary; HPA: antibodies). Use this as a location clue, not an IF validation or protocol. |
| Situation | Likely cause | Next action |
|---|---|---|
| Lens fiber borders are faint or absent. | The expected High lens staining is missing (HPA: Eye, lens fiber cells); a weak run may reflect section or reagent performance (general IHC practice). | Compare a known positive lens section in the same run. Verify primary application and detection, then evaluate retrieval conditions using the positive control (general IHC practice). No GJA3 specific retrieval setting or fixation effect is established by these sources. |
| Nuclei dominate the chromogenic signal. | Nuclear predominance conflicts with the membrane and gap junction location (UniProt Q9Y6H8: subcellular location; HPA: subcellular summary). | Recheck compartment assignment against the counterstain and lens cell borders. Compare with a section omitting primary antibody; if the nuclear signal persists, investigate the detection system (general IHC practice). |
| Negative tissue cells stain strongly. | HPA lists several cells as Not detected and acknowledges disregarded presumed off target binding (HPA: tissue IHC; HPA: reliability description). | Compare the suspect tissue with the lens positive control and a primary omitted control. Avoid calling the unexpected cells GJA3 positive from chromogen alone; review antibody specificity and detection background (general IHC practice). |
| A broad haze obscures lens cell borders. | Diffuse deposition cannot be assigned confidently to the membrane location (UniProt Q9Y6H8: subcellular location). Background may arise from reagent concentration, blocking, or detection chemistry (general IHC practice). | Inspect the primary omitted control, then adjust blocking, washes, or detection exposure according to the assay controls. Score only staining with discernible cellular placement (general IHC practice). |
| The result looks positive in heart muscle, parathyroid gland, or placenta. | HPA reports tissue enhanced RNA there, but the supplied positive protein IHC observation is in lens fiber cells (HPA: RNA specificity; HPA: tissue IHC). | Describe those sections as unconfirmed by the supplied protein pattern. Compare their compartment staining with a lens positive control and assess specificity before interpreting expression (UniProt Q9Y6H8: subcellular location; general IHC practice). |
| An IF/ICC image shows diffuse signal or lacks clear membrane staining. | HPA supplies a Membrane summary but no ICC/IF cell line images or ICC validation status for HPA014821 (HPA: subcellular summary; HPA: antibodies). | Report the IF/ICC result as unresolved against the available evidence. Use appropriate imaging and antibody controls to assess localisation (general IF practice); this IHC section does not establish an IF/ICC protocol. |
Experiment evidence
IHC & IF images showing GJA3 staining
A30696 · IHCImmunohistochemistry analysis of paraffin-embedded human lung carcinoma tissue, using GJA3 Antibody. The picture on the right is blocked wit
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000121743-GJA3/tissue/cerebral+cortex#imid_4304896
HPA · EyeHuman Protein Atlas IHC, Eye. Source: https://www.proteinatlas.org/ENSG00000121743-GJA3/tissue/retina#imid_442
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000121743-GJA3/tissue/colon#imid_4304806
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000121743-GJA3/tissue/liver#imid_4304823
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for GJA3 IHC & IF
🧪Run eye first: lens fiber cells should stain (HPA: High in lens fiber cells). Run adipose tissue as a negative, focusing on adipocytes (HPA: Not detected in adipocytes); any non-lens-fiber cells present on the eye section should lack specific junctional staining (UniProt Q9Y6H8: gap-junction localization).
Positive control tissue: Eye (Lens fiber cells, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for GJA3; derive a cell-line control from the positive tissue's cell type (Lens fiber cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary (secondary-only) control, an isotype control matched to the primary antibody’s host species and clonality, and a biological negative such as a validated GJA3 knockout or peptide block (selected-SKU caption: peptide-blocked image). For chromogenic IHC, check endogenous peroxidase background on the eye section; for IF, assess lens autofluorescence with an unstained section (standard IHC/IF practice).
⚠️Feasibility: A target-specific fixation window and retrieval dependency are unreported in the supplied evidence; optimize retrieval empirically (standard IHC practice). The selected A30696 paraffin-section caption does not state a fixative, so its fixative is unreported (selected-SKU caption). The evidence does not establish whether frozen sections or IF are easier; lens autofluorescence can complicate IF interpretation (standard IF practice).
HPA tissue IHC evidence for GJA3
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Supported — Presumed off target binding observed and disregarded. External characterization data supports antibody staining but no internal RNA data available for correlation.). 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 |
|---|---|---|---|---|
| Eye | Lens fiber cells | 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 GJA3 IHC Tips
Use junctional staining in lens fiber cells as the reference pattern, and interpret staining in other tissues with appropriate controls (UniProt Q9Y6H8; HPA tissue IHC).
How should I optimize retrieval when GJA3 staining is weak?
Start with citrate buffer at pH 6.0, heated to 95–98 °C for 20 min (page retrieval rule: membrane antigen). Run a known positive lens section alongside the test section, then compare junctional signal and tissue preservation under identical detection conditions (HPA: high staining in lens fiber cells; UniProt Q9Y6H8: gap junction localisation). Allow sections to cool in buffer before washing, and keep the primary antibody dilution and detection time constant while assessing retrieval (general IHC practice). If staining remains weak, test a more intensive retrieval condition on adjacent sections as a controlled fallback, documenting any increase in diffuse staining or tissue damage (general IHC practice).
Could fixation explain weak or uneven GJA3 IHC staining?
Target-specific sensitivity of GJA3 staining to fixation is unknown from the supplied evidence; the selected A30696 caption identifies a paraffin section but does not report its fixative (catalog caption: A30696). Record the fixative, time in fixative, section thickness, and processing history for each case before comparing staining intensity (general IHC practice). Compare suspect sections with a concurrently processed positive lens control using the same pH 6.0 retrieval and detection settings (HPA: high in lens fiber cells; page retrieval rule). If an entire batch stains weakly, repeat the run with documented processing controls before assigning the loss to a GJA3-specific fixation effect (general IHC practice).
What staining pattern should count as GJA3 in tissue sections?
Prioritize crisp signal along contacts between adjacent lens fiber cells, consistent with GJA3 at the cell membrane and gap junction (UniProt Q9Y6H8: localisation; HPA: high in lens fiber cells). A functional junction contains apposed connexin hemichannels, so a cell border pattern is more persuasive than uniform nuclear or diffuse stromal color (UniProt Q9Y6H8: subunit; general IHC interpretation). Evaluate pattern at 2 scales: low magnification for distribution and high magnification for membrane continuity (general IHC practice). Document cytoplasmic signal separately, since the protein has a long cytoplasmic tail but its annotated location is membranous (UniProt Q9Y6H8: topology and localisation).
How can epitope position change the apparent GJA3 IHC pattern?
GJA3 has 4 transmembrane segments and a cytoplasmic C-terminal region spanning residues 223–435 (UniProt Q9Y6H8: topology). Its extracellular loops span residues 41–71 and 174–201, making epitope location relevant when interpreting accessibility after paraffin processing and retrieval (UniProt Q9Y6H8: topology; general IHC practice). The record lists 0 annotated isoforms and 0 glycosylation sites; neither establishes where the catalog antibody binds (UniProt Q9Y6H8: annotations). The A30696 image includes peptide blocking, but the supplied caption gives no peptide sequence, so use an epitope map only if one is independently documented for that antibody (catalog caption: A30696).
How should I assess GJA3 by IF alongside a cell identity marker?
For a separate IF experiment, multiplex GJA3 with a validated lens fiber cell marker and inspect whether junctional signal occurs in the expected cells (HPA: high in lens fiber cells; UniProt Q9Y6H8: gap junction localisation). Choose spectrally separated dyes, considering a far red channel around 650–700 nm when shorter wavelength tissue autofluorescence is troublesome (general IF practice). Match permeabilisation to the documented antibody epitope: a cytoplasmic epitope may require detergent access, whereas an accessible extracellular epitope may be assessed without it (UniProt Q9Y6H8: topology; general IF practice). Include single label and no primary controls to check bleed through and autofluorescence; the supplied HPA record reports 0 cell lines with ICC/IF images (HPA subcellular record; general IF practice).
How can I separate GJA3 signal from chromogenic background?
First inspect a no primary control and the positive lens control within the same staining run (general IHC practice; HPA: high in lens fiber cells). Use a peroxidase block before chromogenic detection, and compare DAB development times across sections to identify endogenous enzyme activity or overdevelopment (general IHC practice). The A30696 paraffin lung carcinoma image includes a synthesized peptide block, which supports a competition check for that image but does not establish the identity of every stained cell (catalog caption: A30696). If diffuse color persists, compare 2 adjacent sections with identical retrieval and different primary antibody dilutions while keeping the detection sequence fixed (general IHC practice).
What is a defensible way to quantify GJA3 IHC staining? ⚠ ANSWER MARKED FOR VERIFICATION
Define the analyzable lens fiber region before scoring and exclude folds, torn edges, and visibly damaged areas using the same rule for every section (HPA: lens fiber cell expression; general IHC practice). Report the percentage of fiber area showing junctional signal and its intensity, or apply an H-score only when positive cells can be segmented consistently (general IHC quantification practice). For image analysis, count positive junctional profiles per mm² of analyzable tissue or measure positive interface length against total evaluable cell interface length (general IHC quantification practice). Keep retrieval, exposure or scanning, color thresholds, and control tissue constant across groups; show separate scores for membrane and diffuse staining (UniProt Q9Y6H8: localisation; general IHC practice).
When is a positive GJA3 IHC result convincing?
A convincing result shows junction associated staining in lens fiber cells and reproduces that pattern in a concurrently stained positive control (HPA: high in lens fiber cells; UniProt Q9Y6H8: gap junction localisation). Interpret staining in other cell types cautiously because the HPA tissue profile notes presumed off target binding and lacks internal RNA correlation (HPA: reliability description). Reject isolated nuclear color, section edge gradients, necrotic deposits, and color present in the no primary control as evidence of GJA3 localisation (UniProt Q9Y6H8: membrane localisation; general IHC practice). Compare at least 2 independent sections or runs before calling an unexpected pattern reproducible, and document the staining compartment alongside the score (general IHC practice).
Boster reagents
Best GJA3 / Gap junction alpha-3 protein IHC Antibodies
A30696 has an IHC figure from paraffin-embedded human lung carcinoma tissue; IF and ICC are listed applications, with Human, Mouse and Rat reactivity listed (catalog; IHC image caption).
Real IHC data
Anti-GJA3/Connexin 46 Antibody
Cat # A30696
A30696 is shown in IHC on paraffin-embedded human lung carcinoma tissue, with a peptide-blocked comparison (IHC image caption). IF and ICC are listed applications, but no IF image is supplied; Human, Mouse and Rat are listed as reactive species (catalog).
Which to pick: Choose A30696 for paraffin-section tissue IHC because its own figure shows that preparation; the fixative is unreported (IHC image caption). For IF/ICC, A30696 is the listed option, though no IF image is supplied (catalog). It is also the listed cross-species option because this rabbit polyclonal antibody lists Human, Mouse and Rat reactivity; the supplied IHC figure shows human tissue only (catalog; IHC image caption).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q9Y6H8 (CXA3_HUMAN, Gap junction alpha-3 protein).
- Human Protein Atlas. GJA3 tissue IHC expression (reliability: Supported).
- Human Protein Atlas. GJA3 subcellular location (ICC-IF): Membrane.
- Human Protein Atlas. GJA3 antibody validation summary (1 antibodies).
- The role of DNMT3B, GSK-3β and GJA3 in lens epithelial cell apoptosis and age-related cataract. BMC ophthalmology 2026 — PMC13543546.
- B-RAF mutation and accumulated gene methylation in aberrant crypt foci (ACF), sessile serrated adenoma/polyp (SSA/P) and cancer in SSA/P. British journal of cancer 2015 — PMC4453443.
- PubMed PMID:10205266 — UniProt-cited evidence.
- PubMed PMID:15057823 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for GJA3 (Gap junction alpha-3 protein). Expected localisation Cell membrane and gap junction expected (UniProt). Antigen retrieval: Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen). Validated IHC antibody: A30696 at 1:100 (the product's own IHC validation image is shown). Controls (HPA): positive Eye (Lens fiber cells); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human lung carcinoma tissue; fixative not specified (datasheet A30696); 2. Fixation: Image fixative and duration unreported (datasheet A30696); 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-GJA3, 1:100 (datasheet A30696); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections (standard IHC practice; not target-specific); Caveat: Presumed off-target binding may complicate interpretation (HPA tissue IHC); Isoform / epitope: No isoforms annotated; extracellular vs cytoplasmic epitope side matters (UniProt); Regulation: No expression regulation annotated (UniProt). Evidence: UniProt Q9Y6H8, HPA tissue IHC · Supported, HPA ICC-IF · Membrane, Datasheet A30696, PMC13543546, PMC4453443. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/GJA3/immunohistochemistry-ihc-guide.