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DDX1 / ATP-dependent RNA helicase DDX1 · IHC design guide
Design Immunohistochemistry for DDX1
Plan DDX1 paraffin IHC around the ubiquitous nuclear tissue pattern (HPA tissue IHC). This guide covers consistent fixation, antibody titration, chromogenic detection, and nuclear scoring.
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
DDX1 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 tissue (HPA tissue IHC); cytoplasm is also annotated (UniProt) | |
| Staining pattern | Ubiquitous nuclear staining across tissue cell types (HPA tissue IHC) | |
| Antigen retrieval | EDTA pH 8.0 HIER, heat-mediated (datasheet A03727-1) | |
| Positive control | Appendix+4 more · see all | |
| Negative control | None in HPA (detected in all 44 tissues); use no-primary + isotype controls |
Important caveats
Reasons your staining may differ from the expected pattern.
| Fixation | Keep fixation conditions consistent across sections. (standard IHC practice; not target-specific) | |
| Caveat | Transcriptional state may shift nuclear versus cytosolic signal (UniProt) | |
| Regulation | Highest transcription in neuroectoderm (UniProt) | |
| Isoform / epitope | 3 isoforms; epitope coverage needs checking (UniProt) |
Section 1
Recommended DDX1 IHC & IF Protocols
Compare the catalog antibody’s IHC-P protocol (datasheet A03727-1) with 2 published DDX1 IHC workflows for hepatocellular and colorectal carcinoma specimens (PMC10921000; PMC6113447).
| Sample | Paraffin-embedded rat testis tissue; fixative not specified (datasheet A03727-1) |
| Fixation | Image fixative and duration unreported (datasheet A03727-1); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: EDTA pH 8.0 (datasheet A03727-1); 20 min, 95–100 °C (standard) |
| Peroxidase block | 3% H2O2, 10 min, room temperature (standard) |
| Blocking | 10% goat serum (datasheet A03727-1) |
| Primary antibody | Rabbit anti-DDX1, 0.5-1μg/ml (datasheet A03727-1) |
| Primary incubation | Overnight at 4 °C (datasheet A03727-1) |
| Detection | Streptavidin-biotin complex (SABC), DAB chromogen (datasheet A03727-1) |
| Counterstain | Hematoxylin, blue, dehydrate and mount (standard) |
| Expected result | DDX1-positive staining in glandular cells of appendix (HPA tissue IHC: High). HPA tissue profile: Ubiquitous nuclear expression. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated EDTA pH 8.0 retrieval for the catalog antibody (datasheet A03727-1); the published excerpts provide no retrieval conditions to compare (PMC10921000; PMC6113447).
Section 2
What Is the Expected DDX1 Staining Pattern?
DDX1 should appear predominantly nuclear in paraffin sections, with possible cytoplasmic staining: HPA describes ubiquitous nuclear expression, and UniProt lists both nuclear and cytoplasmic localization (HPA: tissue IHC profile; UniProt Q92499: subcellular location). High staining is reported in several cell populations, including appendix glandular cells, bone marrow hematopoietic cells, and caudate neurons (HPA: tissue IHC). The tissue IHC profile has Enhanced reliability, with medium consistency between antibody staining and RNA expression (HPA: tissue IHC reliability). DDX1 has no transmembrane segment (UniProt Q92499: topology).
| Nuclear chromogen is visible across tissue cells, with some weaker cytoplasmic staining. | This fits the reported ubiquitous nuclear IHC profile and the additional cytoplasmic localization (HPA: tissue IHC profile; UniProt Q92499: subcellular location). Judge intensity against nearby cells and controls; HPA reports High staining in appendix glandular cells and bone marrow hematopoietic cells (HPA: tissue IHC). |
| Staining is strong only along cell borders, while nuclei remain clear. | An exclusively membranous pattern conflicts with the nuclear IHC profile and the lack of a transmembrane segment (HPA: tissue IHC profile; UniProt Q92499: topology). Treat it as suspect and compare antibody and detection controls (general IHC practice). Cytoplasmic staining alone is less decisive because UniProt also places DDX1 in the cytoplasm (UniProt Q92499: subcellular location). |
| A cell population stains intensely while expected positive cells on the same section do not. | Investigate cross-reactivity or endogenous detection activity (general IHC practice). HPA reports High staining in colon endothelial cells and cerebral cortex glial cells, but its ubiquitous nuclear profile does not define other cell types as negative (HPA: tissue IHC). Cell identity alone cannot establish a false positive. |
| Brown signal spreads uniformly over cells, stroma, or the entire section. | Diffuse signal that obscures nuclei is hard to reconcile with the nuclear IHC profile (HPA: tissue IHC profile). Excess detection background, inadequate blocking or washing, and overly concentrated antibody are general possibilities; assess them with a no-primary control and controlled protocol adjustments (general IHC practice). |
| No staining appears in the test section or a known-positive control section. | If an HPA-reported High population is present yet unstained, interpret the run cautiously (HPA: tissue IHC). Check control tissue, primary-antibody use, detection reagents, and retrieval against the validated IHC-P procedure (general IHC practice). A blank test section alone does not prove biological absence. |
💡Expected DDX1 appearanceCall the IHC result positive when interpretable nuclear staining is present in tissue cells, including an HPA-reported High population used as a positive reference; weaker cytoplasmic signal can fit DDX1, whereas isolated cell-border or control-matched diffuse staining is suspect (HPA: tissue IHC profile and levels; UniProt Q92499: subcellular location and topology; general IHC practice).
| Tissue and cell context | HPA calls tissue RNA specificity low and describes ubiquitous nuclear protein expression; it lists High staining in appendix glandular cells, breast adipocytes, cerebellar granular-layer cells, and other specified populations (HPA: tissue IHC). Those examples guide positive-control selection but do not set a universal intensity threshold for every cell. |
| Localization and biological state | UniProt lists nucleus, cytosol, cytoplasmic granules, and mitochondrion, with stress-associated granules and DNA-damage-associated foci under stated conditions (UniProt Q92499: subcellular location). Do not require puncta in untreated tissue or use a punctate pattern alone to identify a specific biological state. |
| Isoforms, processing, and epitope coverage | UniProt lists 3 isoforms, a single stated chain spanning residues 1–740, and no signal peptide or propeptide (UniProt Q92499: isoforms and processing). The payload gives no antibody epitope, so staining cannot be assigned to a particular isoform or epitope-containing form. |
| Antibody validation | HPA lists two antibodies with Enhanced IHC and ICC validation and one with Supported IHC validation (HPA: antibody validation). Enhanced IHC supports the reported pattern through independent antibodies or orthogonal data; it does not establish specificity for the catalog antibody in every specimen. |
| IF/ICC Q: Where should fluorescence appear? | A: Mainly in the nucleoplasm, with additional cytosolic signal; HPA marks both locations Supported in ICC-IF and lists images from A-431, U-251MG, and U2OS (HPA: subcellular ICC-IF). This localization answer does not define an IF/ICC protocol or make fluorescence intensity directly comparable with chromogenic IHC. |
| Situation | Likely cause | Next action |
|---|---|---|
| Positive-control nuclei are blank. | The run may have failed, or the chosen section may lack an identifiable HPA-reported High population (HPA: tissue IHC; general IHC practice). | Confirm the control's cell population, then verify primary-antibody application, detection reagents, and antigen retrieval against the validated IHC-P procedure (general IHC practice). No DDX1-specific retrieval condition or fixation sensitivity is supplied. |
| Signal is mostly membranous. | Cell-border staining is discordant with ubiquitous nuclear IHC expression and no transmembrane segment (HPA: tissue IHC profile; UniProt Q92499: topology). | Compare a positive-control section and no-primary control; if the border pattern persists only with primary antibody, reassess antibody specificity (general IHC practice). |
| Diffuse chromogen obscures nuclear detail. | Nonspecific binding, excessive detection signal, or inadequate washing can create diffuse background (general IHC practice). | Check the no-primary control, then review blocking, washes, antibody dilution, and detection time within the validated workflow (general IHC practice). Preserve a readable nuclear counterstain for compartment assessment. |
| Signal remains in the no-primary control. | Primary-independent staining can arise from endogenous detection activity or detection reagents (general IHC practice). | Review the detection system and its applicable endogenous-activity blocking step; compare control and test sections before assigning DDX1 positivity (general IHC practice). |
| Cytoplasmic or punctate signal exceeds nuclear staining. | DDX1 can occur in cytosol and granules under described conditions, but HPA's tissue IHC profile is nuclear (UniProt Q92499: subcellular location; HPA: tissue IHC profile). | Check whether nuclei remain detectably positive, examine morphology and controls, and report the compartment pattern without assigning stress or DNA damage from staining alone (general IHC practice). |
| Only an unexpected cell population stains strongly. | Cross-reactivity or endogenous detection activity is possible; HPA reports a ubiquitous nuclear profile and provides no negative cell list (HPA: tissue IHC; general IHC practice). | Verify cell identity and nuclear localization, inspect the no-primary control, and compare with an HPA-reported High population before interpreting cell-restricted staining (HPA: tissue IHC; general IHC practice). |
Experiment evidence
IHC & IF images showing DDX1 staining
A03727-1 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (A03727-1). DDX1 was detected in paraffin-embedded section of rat testis tissue. Heat mediated
A03727-1 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (A03727-1). DDX1 was detected in paraffin-embedded section of mouse testis tissue. Heat mediat
A03727-1 · IFIF analysis of DDX1 using anti-DDX1 antibody (A03727-1). DDX1 was detected in immunocytochemical section of U20S cells. Enzyme antigen retri
M03727 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727). DDX1 was detected in a paraffin-embedded section of human prostatic acinar adenocarc
M03727 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727). DDX1 was detected in a paraffin-embedded section of human colorectal adenocarcinoma
M03727 · IFIF analysis of DDX1 using anti-DDX1 antibody (M03727). DDX1 was detected in an immunocytochemical section of Hela cells. Enzyme antigen retr
M03727-2 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727-2). DDX1 was detected in a paraffin-embedded section of human cervica squamous carcino
M03727-2 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727-2). DDX1 was detected in a paraffin-embedded section of human ovarian serous adenocarc
M03727-1 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727-1). DDX1 was detected in paraffin-embedded section of human gastric cancer tissue. Hea
M03727-1 · IHCIHC analysis of DDX1 using anti-DDX1 antibody (M03727-1). DDX1 was detected in paraffin-embedded section of human pancreatic cancer tissue.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000079785-DDX1/tissue/cerebral+cortex#imid_11610811
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000079785-DDX1/tissue/colon#imid_11610737
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000079785-DDX1/tissue/liver#imid_11610738
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000079785-DDX1/tissue/kidney#imid_11611315
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA034502; green = DDX1, blue = nucleus, red = microtubules.
HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA034502; green = DDX1, blue = nucleus, red = microtubules.
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for DDX1 IHC & IF
🧪Run appendix first and look for staining in glandular cells (HPA: High in appendix glandular cells). HPA detects DDX1 in all 44 scored tissues, so there is no supported negative tissue; use no-primary and isotype controls, and treat cells with background-only signal on the positive slide as unstained rather than assuming they are biologically DDX1-negative (HPA: no negative tissue rows).
Positive control tissue: Appendix (Glandular cells, HPA High)
Negative control tissue: None in HPA: DDX1 is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.
ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show DDX1 in A-431, U-251MG, U2OS, with annotated localisation: Nucleoplasm (supported) (HPA subcellular).
Technical controls: Include a no-primary, secondary-only section, a matched rabbit IgG isotype control, and DDX1 knockout material where available as a biological specificity control (selected-SKU caption: rabbit anti-DDX1 antibody; standard IHC practice). Block endogenous peroxidase and assess endogenous biotin in appendix sections because the reported chromogenic method uses a biotinylated secondary, streptavidin–biotin complex and DAB (selected-SKU tissue-IHC caption).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the selected-SKU paraffin-section caption does not state the fixative (selected-SKU tissue-IHC caption). That caption reports heat retrieval in EDTA at pH 8.0, but does not establish that retrieval is required under other conditions (selected-SKU tissue-IHC caption). Whether frozen sections or IF are easier is unreported; in appendix, evaluate glandular signal against possible luminal or tissue pigment deposits rather than scoring deposits as cellular staining (HPA: High in appendix glandular cells; standard IHC practice).
HPA tissue IHC evidence for DDX1
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 |
|---|---|---|---|---|
| Appendix | Glandular cells | High | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | High | Protein (IHC) | HPA → |
| Breast | Adipocytes | High | Protein (IHC) | HPA → |
| Caudate | Neuronal cells | High | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | High | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| None in HPA: DDX1 is detected in all 44 scored tissues. Use a no-primary (secondary-only) and an isotype control instead. | ||||
Section 3
Advanced DDX1 IHC Tips
Troubleshoot DDX1 staining by checking retrieval, compartment-specific signal, controls and scoring in chromogenic paraffin-section IHC.
Which retrieval conditions should I try first for weak DDX1 staining?
Start with heat-mediated retrieval in EDTA at pH 8.0 for the catalog antibody (datasheet A03727-1). The selected paraffin-section image used this retrieval before incubation with 1 µg/ml primary antibody overnight at 4°C, so reproduce those conditions when comparing staining (caption A03727-1). If signal remains weak, adjust heating duration and cooling consistently across sections, then assess morphology and nuclear staining together; excessive retrieval can damage tissue or increase background (standard IHC practice). Record each change against an identically processed control section, because DDX1 is mainly nucleoplasmic and also occurs in the cytosol (HPA: subcellular).
Could fixation explain weak or uneven DDX1 staining in paraffin sections?
Target-specific sensitivity of DDX1 to fixation is unknown from the supplied evidence; the selected paraffin-section caption does not state its fixative (caption A03727-1). Document the specimen's fixative, fixation duration and processing history before comparing sections, because fixation and processing can alter epitope access in chromogenic IHC (standard IHC practice). Compare specimens with similar handling using the same EDTA pH 8.0 retrieval and 1 µg/ml primary concentration documented for this antibody (caption A03727-1). If staining varies, review morphology and internal cellular staining before attributing the difference to DDX1 abundance; neither HPA expression patterns nor DDX1 modifications establish a fixation effect (HPA: tissue IHC; UniProt Q92499).
How should I assess nuclear versus cytoplasmic DDX1 staining?
Expect widespread nuclear staining as a reference pattern: tissue IHC describes ubiquitous nuclear expression, while subcellular data place DDX1 mainly in the nucleoplasm with additional cytosolic localisation (HPA: tissue IHC; HPA: subcellular). Score nuclear and cytoplasmic chromogen separately in intact cells, using the counterstain to define nuclei and checking that the section remains well preserved (standard IHC practice). DDX1 can enter nuclei during active transcription and accumulate in cytosol when transcription is low (UniProt Q92499). Focal redistribution can occur after irradiation or stress, so record treatment history before interpreting a changed compartment pattern as assay failure (UniProt Q92499).
Can epitope location affect interpretation across DDX1 isoforms?
DDX1 has 3 listed isoforms, but the supplied antibody evidence does not identify the recognized epitope or establish equal recognition of each isoform (UniProt Q92499; caption A03727-1). The canonical protein spans residues 1–740 and contains a helicase ATP-binding region at 2–428, a B30.2/SPRY region at 70–247, and a helicase C-terminal region at 493–681 (UniProt Q92499). Do not assign an absent tissue signal to a particular isoform or modification without epitope information and an independent comparison (standard IHC interpretation). When comparing specimens, retain the same retrieval, antibody concentration and detection conditions so technical variation does not masquerade as isoform-specific staining (caption A03727-1; standard IHC practice).
How can I check a DDX1 IHC pattern by multiplex immunofluorescence?
On a separate IF/ICC validation workflow, pair DDX1 with a validated marker for the cell population being assessed, then check whether its expected nuclear signal occurs in those cells (HPA: tissue IHC; HPA: subcellular). Include single-stain and secondary-only controls to evaluate channel bleed-through and nonspecific fluorescence before interpreting colocalisation (standard IF practice). Choose fluorophores after examining tissue autofluorescence, favoring a spectrally separated channel with lower background for the weaker signal (standard IF practice). Permeabilise sufficiently for antibody access to nucleoplasmic and cytosolic epitopes, since DDX1 has no transmembrane segment; optimise that step for the IF specimen rather than importing the paraffin-section retrieval procedure (UniProt Q92499 topology; standard IF practice).
What should I check when DDX1 staining is diffuse or granular?
First compare stained sections with a primary-omission control and inspect whether chromogen follows intact cells or accumulates at tissue edges, damaged areas or precipitates (standard IHC practice). For a biotin-based DAB workflow, assess endogenous peroxidase and endogenous biotin as possible contributors to background, and confirm that the blocking and detection reagents are appropriate (caption A03727-1; standard IHC practice). The selected image used 10% goat serum blocking, a biotinylated secondary and DAB development, providing concrete conditions to reproduce during troubleshooting (caption A03727-1). Do not discard every punctum automatically: DDX1 can occur in cytoplasmic granules and form DDX1 bodies, so require cellular context and control-dependent signal before calling granularity specific (UniProt Q92499).
How should I quantify DDX1 in chromogenic tissue sections? ⚠ ANSWER MARKED FOR VERIFICATION
Define cell populations and compartments before scoring, because DDX1 is commonly nuclear but can also appear in the cytosol (HPA: tissue IHC; HPA: subcellular). For each prespecified population, report the percentage of positive nuclei and an intensity-based H-score, or count positive cells per mm² when spatial density is the endpoint (standard IHC scoring practice). Normalise nuclear positivity to evaluable nuclei in that population, and normalise density to viable tissue area while excluding folds, necrosis and poorly stained edges (standard IHC scoring practice). Keep retrieval, imaging and intensity thresholds consistent across specimens; report cytoplasmic staining separately rather than folding it into a nuclear score (standard IHC scoring practice).
Which DDX1 signals are credible, and which suggest artefact?
A credible baseline pattern includes staining in intact nuclei across cell populations, consistent with ubiquitous nuclear tissue expression and supported nucleoplasmic localisation (HPA: tissue IHC; HPA: subcellular). Additional cytosolic signal can be biologically plausible, and stress or irradiation can redistribute DDX1 into granules or foci, so interpret unusual patterns alongside specimen treatment history (UniProt Q92499). Treat staining confined to cut edges, necrotic regions or primary-omission controls as suspect; check endogenous enzyme activity when using DAB detection (standard IHC practice). The catalog image demonstrates staining in a paraffin section of rat testis, while the listed HPA patterns concern human tissues; compare each specimen against suitable controls before generalising between them (caption A03727-1; HPA: tissue IHC).
Boster reagents
Best DDX1 / ATP-dependent RNA helicase DDX1 IHC Antibodies
Validated anti-DDX1 antibodies have IHC images from human, mouse and rat paraffin sections, plus IF/ICC images from human cells and IF images from human and mouse sections (catalog image captions).
Real IHC data
Anti-DDX1 Antibody ®
Cat # A03727-1
Real IHC data
Anti-DDX1 ® Antibody (monoclonal, 3I10)
Cat # M03727
Real IHC data
Anti-DDX1 ® Antibody (monoclonal, 11E5)
Cat # M03727-2
Real IHC data
Anti-DDX1 ® Antibody (monoclonal, 2D4)
Cat # M03727-1
A03727-1 was imaged by IHC in rat testis (A03727-1 IHC caption); M03727 was imaged in human prostatic acinar adenocarcinoma (M03727 IHC caption). M03727-2 was imaged in human cervical squamous carcinoma (M03727-2 IHC caption); M03727-1 was imaged in human gastric cancer (M03727-1 IHC caption).
Which to pick: For human tissue IHC, choose M03727 if a monoclonal antibody is preferred: clone 3I10 has a paraffin-section image from human prostatic acinar adenocarcinoma (catalog: clone 3I10; M03727 IHC caption). For IF/ICC, choose A03727-1 or M03727; both list IF and ICC and have IF image captions, whereas M03727-1 and M03727-2 list IHC but not IF (catalog: applications and IF captions). For cross-species paraffin IHC, A03727-1 lists human, mouse and rat reactivity and has mouse and rat paraffin-section images (catalog: reactivity; A03727-1 IHC captions); the IHC captions for all four SKUs specify paraffin sections but do not report the fixative (A03727-1, M03727, M03727-1 and M03727-2 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry Q92499 (DDX1_HUMAN, ATP-dependent RNA helicase DDX1).
- Human Protein Atlas. DDX1 tissue IHC expression (reliability: Enhanced).
- Human Protein Atlas. DDX1 subcellular location (ICC-IF): Mainly localized to the nucleoplasm. In addition localized to the cytosol..
- Human Protein Atlas. DDX1 antibody validation summary (3 antibodies).
- DEAD-box helicase 1 inhibited CD8(+) T cell antitumor activity by inducing PD-L1 expression in hepatocellular carcinoma. Cancer science 2024 — PMC10921000.
- ACOD1 deficiency promotes DDX1 methylation-mediated mitochondrial dysfunction and dermal papilla cell senescence in androgenetic alopecia. BMC medicine 2026 — PMC13440255.
- DEAD box protein DDX1 promotes colorectal tumorigenesis through transcriptional activation of the LGR5 gene. Cancer science 2018 — PMC6113447.
- PRMT1-mediated asymmetric dimethylation of arginine residue 602 in DDX1 promotes cholangiocarcinoma progression. Clinical and molecular hepatology 2026 — PMC13129775.
- PubMed PMID:7689221 — UniProt-cited evidence.
- PubMed PMID:14702039 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for DDX1 (ATP-dependent RNA helicase DDX1). Expected localisation Nuclear staining in tissue (HPA tissue IHC); cytoplasm is also annotated (UniProt). Antigen retrieval: EDTA pH 8.0 HIER, heat-mediated (datasheet A03727-1). Validated IHC antibody: A03727-1 at 0.5-1μg/ml (the product's own IHC validation image is shown). Controls (HPA): positive Appendix (Glandular cells); negative None in HPA (detected in all 44 tissues); use no-primary + isotype controls. IHC-P workflow on paraffin sections; fixative unspecified. Protocol steps: 1. Sample: Paraffin-embedded rat testis tissue; fixative not specified (datasheet A03727-1); 2. Fixation: Image fixative and duration unreported (datasheet A03727-1); 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 A03727-1); 20 min, 95–100 °C (standard); 6. Peroxidase block: 3% H2O2, 10 min , room temperature (standard); 7. Blocking: 10% goat serum (datasheet A03727-1); 8. Primary antibody: Rabbit anti-DDX1, 0.5-1μg/ml (datasheet A03727-1); 9. Primary incubation: Overnight at 4 °C (datasheet A03727-1). Watch for: Fixation: Keep fixation conditions consistent across sections. (standard IHC practice; not target-specific); Caveat: Transcriptional state may shift nuclear versus cytosolic signal (UniProt); Isoform / epitope: 3 isoforms; epitope coverage needs checking (UniProt); Regulation: Highest transcription in neuroectoderm (UniProt). Evidence: UniProt Q92499, HPA tissue IHC · Enhanced, HPA ICC-IF · Mainly localized to the nucleoplasm. In addition localized to the…, Datasheet A03727-1, PMC10921000, PMC6113447. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/DDX1/immunohistochemistry-ihc-guide.