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TNNI2 / Troponin I, fast skeletal muscle · IHC design guide
Design Immunohistochemistry for TNNI2
Plan paraffin-section TNNI2 IHC around cytoplasmic staining in skeletal myocytes (HPA tissue IHC). Use the catalog antibody's 0.5–1 μg/mL IHC range (datasheet A07355-2) to guide chromogenic staining and scoring.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
TNNI2 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 skeletal muscle (HPA tissue IHC) | |
| Staining pattern | High cytoplasmic staining in skeletal myocytes (HPA tissue IHC) | |
| Antigen retrieval | Citrate pH 6 HIER, heat-mediated (datasheet A07355-2) | |
| Positive control | Skeletal muscle | |
| Negative control | Adipose tissue+4 more · see all |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A07355-2) | |
| Caveat | Fast-skeletal identity may affect staining across fibers (UniProt) | |
| Regulation | No expression regulator specified (UniProt) | |
| Isoform / epitope | 2 isoforms; antibody epitope coverage is unknown (UniProt) |
Section 1
Recommended TNNI2 IHC & IF Protocols
The catalog antibody’s IHC-P protocol is paired with one published mouse skeletal-tissue IHC protocol (PMC4207604).
| Sample | Paraffin-embedded human skeletal muscle tissues; fixative not specified (datasheet A07355-2) |
| Fixation | Image fixative and duration unreported (datasheet A07355-2); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Citrate pH 6, 20 min (datasheet A07355-2) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A07355-2) |
| Primary antibody | Rabbit anti-TNNI2, 0.5-1μg/ml (datasheet A07355-2) |
| Primary incubation | Overnight at 4 °C (datasheet A07355-2) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A07355-2) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | TNNI2-positive staining in myocytes of skeletal muscle (HPA tissue IHC: High). HPA tissue profile: Cytoplasmic expression in skeletal muscle. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated citrate retrieval at pH 6 (datasheet A07355-2); the published protocol does not specify retrieval (PMC4207604).
Section 2
What Is the Expected TNNI2 Staining Pattern?
In paraffin-section IHC, expect TNNI2 staining in the cytoplasm of skeletal muscle myocytes; HPA reports high staining with Enhanced reliability, reflecting consistency between antibody staining and RNA expression (HPA tissue IHC). TNNI2 is a thin-filament regulatory protein that binds actin and tropomyosin and has no annotated transmembrane segment (UniProt P48788 function, subunit, topology).
| Strong cytoplasmic chromogen in skeletal muscle myocytes, with a readable counterstain. | This matches the reported high myocyte staining and cytoplasmic tissue pattern (HPA tissue IHC). Score signal in identifiable myocytes rather than counting general tissue colour as positive. HPA's Enhanced rating supports the tissue pattern, but does not validate every antibody or preparation (HPA tissue IHC). |
| Predominantly nuclear, extracellular, or sharply surface-restricted staining in skeletal muscle. | Treat the compartment mismatch as a possible artefact until it is checked against cytoplasmic staining in a positive section (HPA tissue IHC; general IHC practice). UniProt lists no transmembrane segment and does not annotate a subcellular location, so topology alone cannot identify the cause (UniProt P48788 topology, subcellular record). |
| Clear staining in adipocytes or bone marrow hematopoietic cells. | These cells are reported as not detected in tissue IHC (HPA tissue IHC). Consider antibody cross-reactivity or endogenous detection activity, especially if the signal appears outside identifiable skeletal myocytes; test detection-only and negative-tissue controls before assigning TNNI2 expression (general IHC practice). |
| Diffuse colour across myocytes, stroma, and blank areas of the section. | A widespread, poorly localized deposit does not reproduce the cytoplasmic myocyte pattern (HPA tissue IHC). Examine background in a section processed without primary antibody, then review blocking, washing, detection chemistry, and antibody concentration as general IHC variables (general IHC practice). |
| No detectable staining in a skeletal muscle positive-control section. | That conflicts with HPA's high myocyte signal (HPA tissue IHC). Check section integrity, primary-antibody and detection steps, and counterstain visibility before interpreting test sections as negative (general IHC practice). No TNNI2-specific fixation or retrieval sensitivity is established by the supplied records. |
💡Expected TNNI2 appearanceCall a section positive when identifiable skeletal muscle myocytes show strong cytoplasmic staining (HPA tissue IHC); isolated nuclear deposits or staining in HPA-negative cell types warrant artefact checks (HPA tissue IHC; general IHC practice).
| Positive and negative tissue context | Skeletal muscle myocytes are the documented high-staining reference; adipocytes and bone marrow hematopoietic cells are documented as not detected (HPA tissue IHC). Use those contrasts to judge specificity within the sampled material, while recognizing that HPA observations do not guarantee every preparation's result. |
| Tissue IHC versus IF/ICC localisation | How should IF/ICC be read? HPA reports a main plasma-membrane location and an additional intermediate-filament location in ICC-IF, whereas tissue IHC reports cytoplasmic skeletal muscle expression (HPA subcellular ICC-IF; HPA tissue IHC). Interpret each assay in its own specimen and detection context. |
| Antibody evidence | HPA lists HPA055938 and CAB018697 as IHC Enhanced; HPA055938 is also ICC Approved (HPA antibodies). Those statuses support the reported applications and tissue-pattern assessment. They do not establish a dilution, retrieval setting, or validation status for a different catalog antibody. |
| Isoforms and protein features | UniProt lists two isoforms and modified residues, including acetylation and phosphorylation (UniProt P48788 isoforms, modified residues). Without an antibody epitope or isoform-specific validation in the supplied evidence, do not infer which form contributes to a positive section or whether a modification changes staining. |
| Paraffin-section workflow | Antigen retrieval and blocking are general IHC variables; compare documented conditions and include suitable controls when optimizing an assay (general IHC practice). The supplied UniProt and HPA records do not report a TNNI2-specific retrieval requirement or fixation effect. |
| Situation | Likely cause | Next action |
|---|---|---|
| Skeletal muscle positive control is blank. | A missed or ineffective primary-antibody, retrieval, or detection step can eliminate visible chromogen (general IHC practice). The result conflicts with high skeletal myocyte staining (HPA tissue IHC); the source records do not identify a TNNI2-specific failing step. | Confirm that tissue and counterstain are visible, then check each reagent and incubation against the antibody's documented IHC procedure. Compare an appropriately controlled retrieval condition if needed (general IHC practice). |
| Colour obscures cell boundaries throughout the section. | Excess antibody or detection background, inadequate blocking, or insufficient washing can reduce contrast (general IHC practice). Diffuse colour cannot be scored as the reported cytoplasmic myocyte pattern (HPA tissue IHC). | Review the antibody's documented working concentration, strengthen routine blocking and washing, and inspect a section without primary antibody (general IHC practice). Score only cell-associated signal that remains interpretable. |
| Adipocytes or marrow hematopoietic cells stain as strongly as myocytes. | Those cells are listed as not detected in the supplied tissue profile (HPA tissue IHC). Cross-reactivity or endogenous detection activity is possible, although the staining alone cannot distinguish them (general IHC practice). | Compare a detection-only control with the stained section, review endogenous-enzyme blocking if using enzyme-based detection, and reassess antibody specificity with documented controls (general IHC practice). |
| Signal appears mainly in nuclei or extracellular spaces. | This conflicts with the cytoplasmic tissue-IHC profile (HPA tissue IHC). Tissue deposits, detection background, or misidentified structures can produce misleading localisation (general IHC practice); UniProt's lack of a transmembrane segment does not diagnose the artefact (UniProt P48788 topology). | Inspect morphology alongside the counterstain, compare with the skeletal muscle positive control, and check a section processed without primary antibody before calling the signal TNNI2 (general IHC practice). |
| Signal is uneven across a section or between staining runs. | Uneven reagent coverage, section handling, or detection development can vary apparent intensity (general IHC practice). HPA reports high myocyte staining but does not establish uniform staining in every field or run (HPA tissue IHC). | Check section coverage and processing consistency, then compare runs using the same skeletal muscle control and scoring criteria (general IHC practice). Avoid treating technical variation alone as a change in TNNI2 expression. |
Experiment evidence
IHC & IF images showing TNNI2 staining
A07355-2 · IHCIHC analysis of TNNI2 using anti-TNNI2 antibody (A07355-2). TNNI2 was detected in paraffin-embedded section of human skeletal muscle tissues
A07355-2 · IHCIHC analysis of TNNI2 using anti-TNNI2 antibody (A07355-2). TNNI2 was detected in paraffin-embedded section of mouse skeletal muscle tissues
A07355-2 · IFIF analysis of TNNI2 using anti-TNNI2 antibody (A07355-2). TNNI2 was detected in a paraffin-embedded section of rat skeletal muscle tissue.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000130598-TNNI2/tissue/cerebral+cortex#imid_16775811
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000130598-TNNI2/tissue/colon#imid_16777584
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000130598-TNNI2/tissue/liver#imid_16777621
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000130598-TNNI2/tissue/kidney#imid_16777622
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA055938; green = TNNI2, blue = nucleus, red = microtubules.
HPA · ICC-IF CACO-2Human Protein Atlas immunofluorescence, CACO-2, antibody HPA055938; green = TNNI2, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for TNNI2 IHC & IF
🧪Run skeletal muscle first; myocytes should stain (HPA: High in skeletal muscle myocytes). Use adipose tissue as the negative, with adipocytes at background (HPA: Not detected in adipose adipocytes); on the positive slide, assess nonmyocyte cells as internal background controls alongside the stained myocytes (HPA: High in skeletal muscle myocytes).
Positive control tissue: Skeletal muscle (Myocytes, HPA High)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show TNNI2 in CACO-2, U2OS, hTCEpi, with annotated localisation: Plasma membrane (approved) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only control and a concentration-matched rabbit IgG isotype control matched for clonality where applicable (selected-SKU caption: rabbit primary and goat anti-rabbit secondary). Use TNNI2-knockout material or validated antigen-peptide competition as a biological negative; for the skeletal muscle DAB assay, quench endogenous peroxidase and check for endogenous biotin signal with the avidin–biotin detection system (selected-SKU caption: skeletal muscle, SABC and DAB).
⚠️Feasibility: A target-specific fixation window and fixation effect are unreported, and the selected-SKU paraffin-section caption does not state the fixative (selected-SKU caption: fixative not stated). The reported IHC workflow uses heat retrieval in citrate buffer at pH 6 for 20 minutes, but whether retrieval is essential has not been established (selected-SKU caption). There is no supplied comparison showing that frozen sections or IF are easier; skeletal muscle background from endogenous peroxidase or biotin should be checked for this DAB/SABC workflow (selected-SKU caption: skeletal muscle, SABC and DAB).
HPA tissue IHC evidence for TNNI2
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Enhanced — High 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 |
|---|---|---|---|---|
| Skeletal muscle | Myocytes | 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 TNNI2 IHC Tips
Troubleshoot TNNI2 staining in paraffin sections by checking retrieval, tissue pattern, controls, and scoring before interpreting signal.
What retrieval should I try first if TNNI2 staining is weak?
Start with heat-mediated citrate retrieval at pH 6 for 20 minutes on paraffin sections (datasheet A07355-2). The selected antibody’s tissue image used this treatment before overnight primary incubation at 4°C (datasheet A07355-2). If staining remains weak, check section adhesion, heating consistency, primary-antibody concentration, and development time on a skeletal-muscle control before changing retrieval conditions (standard IHC practice; HPA tissue IHC: high in skeletal-muscle myocytes). If testing another buffer or pH, change one condition at a time and compare signal with background on adjacent sections (standard IHC practice).
How should I troubleshoot possible fixation effects on TNNI2 staining?
The selected tissue caption identifies a paraffin section but does not state its fixative, so target-specific fixation sensitivity is unknown (datasheet A07355-2). Record the fixative, fixation duration, specimen thickness, and processing history for each sample before comparing staining intensities (standard IHC practice). Compare similarly processed skeletal-muscle sections using the same pH 6 citrate retrieval and 20-minute heating step (datasheet A07355-2; standard IHC practice). If a processing batch stains poorly, inspect section preservation and run a known positive section alongside it; neither tissue expression nor protein topology establishes a TNNI2-specific fixation effect (HPA tissue IHC; UniProt P48788; standard IHC practice).
Which staining compartment should I expect in skeletal-muscle IHC?
Assess staining in skeletal-muscle myocytes, where tissue IHC reports high TNNI2 signal with a cytoplasmic pattern (HPA tissue IHC). TNNI2 participates in the thin-filament troponin complex and binds actin and tropomyosin, supporting evaluation within muscle fibers (UniProt P48788). HPA subcellular imaging separately reports plasma-membrane and intermediate-filament locations; those cell-image observations should be recorded separately from the skeletal-muscle tissue pattern (HPA subcellular; HPA tissue IHC). If staining is predominantly nuclear or confined to section edges, compare it with a positive skeletal-muscle section and a no-primary control before assigning localisation (standard IHC practice; HPA tissue IHC).
Can this staining distinguish TNNI2 isoforms or modified forms?
TNNI2 has 2 listed isoforms, while the supplied tissue caption does not identify the antibody epitope or establish isoform selectivity (UniProt P48788; datasheet A07355-2). The record lists acetylation at residue 2 and phosphorylation at residues 12 and 118, but supplies no evidence that these changes alter this antibody’s staining (UniProt P48788; datasheet A07355-2). Treat positive chromogenic signal as TNNI2-associated staining rather than an isoform or modification readout unless epitope validation supports that claim (standard IHC practice). For discordant samples, compare staining with an independently validated reagent or an orthogonal expression measurement and document the tested epitope when available (standard IHC practice).
How can I assess TNNI2 by multiplex immunofluorescence?
Pair TNNI2 with a validated skeletal-muscle myocyte marker and inspect whether signals occur in the expected cells (HPA tissue IHC: high in myocytes; standard IF practice). Choose spectrally separated fluorophores and favor a longer-wavelength TNNI2 channel if tissue autofluorescence obscures shorter-wavelength signal; include single-stain controls (standard IF practice). For an intracellular epitope, test gentle permeabilisation, but establish epitope accessibility experimentally because the supplied antibody caption does not map its epitope (datasheet A07355-2; standard IF practice). The protein has no transmembrane segment, while HPA cell imaging reports membrane and intermediate-filament locations; compare each pattern with compartment controls (UniProt P48788; HPA subcellular; standard IF practice).
What should I check when DAB background obscures muscle-fiber staining?
The selected paraffin-section image used 10% goat-serum blocking, 1 μg/ml primary antibody, a biotinylated secondary, and DAB development (datasheet A07355-2). For diffuse background, compare a no-primary control, adjust antibody exposure or chromogen development, and check washing and blocking consistency (standard IHC practice). Include an endogenous-peroxidase block before DAB detection and assess possible endogenous-biotin signal when using a biotin-based detection system (standard IHC practice; datasheet A07355-2). Compare background in skeletal-muscle myocytes with adipocytes or other stated HPA-negative cells, while recognizing that a negative reference does not replace a section-specific control (HPA tissue IHC; standard IHC practice).
How should I score TNNI2 IHC across skeletal-muscle sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define skeletal-muscle myocytes as the analysis population and score their cytoplasmic chromogenic signal, consistent with the reported tissue pattern (HPA tissue IHC). Report the percentage of positive myocytes and an H-score based on prespecified intensity categories; keep thresholds and acquisition settings consistent across samples (standard IHC practice). Normalize positive-cell counts to all evaluable myocytes, or report positive area relative to evaluable muscle area when fiber boundaries cannot be scored reliably (standard IHC practice). Exclude folds, necrosis, and section edges using predefined rules, and document retrieval and DAB development conditions before comparing groups (standard IHC practice; datasheet A07355-2).
How do I distinguish genuine TNNI2 signal from staining artefact?
A convincing result places signal in skeletal-muscle myocytes with a cytoplasmic tissue pattern, alongside a positive skeletal-muscle control (HPA tissue IHC; standard IHC practice). Diffuse nuclear staining, edge-only staining, or signal concentrated in necrotic regions warrants review against intact neighboring fibers and a no-primary section (HPA tissue IHC; standard IHC practice). Check an endogenous-peroxidase control if DAB color appears without primary antibody, and investigate biotin-related background with the selected detection system (datasheet A07355-2; standard IHC practice). HPA reports no detection in adipocytes across listed tissues; unexpected staining there calls for control review rather than immediate biological interpretation (HPA tissue IHC; standard IHC practice).
Boster reagents
Best TNNI2 / Troponin I, fast skeletal muscle IHC Antibodies
The catalog antibody has real IHC data from human, mouse and rat paraffin skeletal muscle sections, plus IF data from mouse and rat paraffin skeletal muscle sections (catalog image captions).
Real IHC data
Anti-Troponin I fast skeletal muscle/TNNI2 Antibody ®
Cat # A07355-2
A07355-2 will render with its human skeletal muscle paraffin-section IHC figure (IHC image caption). The same SKU is listed for human, mouse and rat IHC, with additional mouse and rat paraffin-section IF images (catalog applications, reactivity and image captions).
Which to pick: Choose A07355-2 for tissue IHC because its IHC captions show staining in human, mouse and rat skeletal muscle paraffin sections (IHC image captions). For IF, the same SKU has mouse and rat skeletal muscle paraffin-section images; ICC validation and clonality are unreported (IF image captions; catalog). The IHC captions do not report a fixative, so fixation conditions need separate validation (IHC image captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P48788 (TNNI2_HUMAN, Troponin I, fast skeletal muscle).
- Human Protein Atlas. TNNI2 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. TNNI2 subcellular location (ICC-IF): Mainly localized to the plasma membrane. In addition localized to the intermediate filaments..
- Human Protein Atlas. TNNI2 antibody validation summary (2 antibodies).
- A gain-of-function mutation in Tnni2 impeded bone development through increasing Hif3a expression in DA2B mice. PLoS genetics 2014 — PMC4207604.
- Dose-response effect of L-citrulline on skeletal muscle damage after acute eccentric exercise: an in vivo study in mice. PeerJ 2023 — PMC10734431.
- The sinus venosus myocardium contributes to the atrioventricular canal: potential role during atrioventricular node development?. Journal of cellular and molecular medicine 2015 — PMC4459851.
- LncRNA-TBP mediates TATA-binding protein recruitment to regulate myogenesis and induce slow-twitch myofibers. Cell communication and signaling : CCS 2023 — PMC9835232.
- PubMed PMID:8148383 — UniProt-cited evidence.
- PubMed PMID:10721725 — UniProt-cited evidence.
- PubMed PMID:16554811 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for TNNI2 (Troponin I, fast skeletal muscle). Expected localisation Cytoplasmic staining in skeletal muscle (HPA tissue IHC). Antigen retrieval: Citrate pH 6 HIER, heat-mediated (datasheet A07355-2). Validated IHC antibody: A07355-2 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Skeletal muscle (Myocytes); negative Adipose tissue. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded human skeletal muscle tissues; fixative not specified (datasheet A07355-2); 2. Fixation: Image fixative and duration unreported (datasheet A07355-2); 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: Citrate pH 6 , 20 min (datasheet A07355-2); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A07355-2); 8. Primary antibody: Rabbit anti-TNNI2, 0.5-1μg/ml (datasheet A07355-2); 9. Primary incubation: Overnight at 4 °C (datasheet A07355-2). Watch for: Fixation: Matched tissue-IHC evidence does not establish the fixation claim. Validate the specimen-specific method before use. (selected-SKU IHC image A07355-2); Caveat: Fast-skeletal identity may affect staining across fibers (UniProt); Isoform / epitope: 2 isoforms; antibody epitope coverage is unknown (UniProt); Regulation: No expression regulator specified (UniProt). Evidence: UniProt P48788, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the plasma membrane. In addition localized to…, Datasheet A07355-2, PMC4207604. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/TNNI2/immunohistochemistry-ihc-guide.