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PRIM1 / DNA primase small subunit · IHC design guide
Design Immunohistochemistry for PRIM1
Plan PRIM1 staining in paraffin sections using the IHC-validated antibody and its documented dilution range (datasheet: A30648, 1:100–1:300). Compare the reported cytoplasmic pattern across tissues while accounting for the tissue evidence’s uncertain reliability (HPA tissue IHC).
Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use
PRIM1 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 reported; reliability uncertain (HPA tissue IHC) | |
| Staining pattern | Cytoplasmic staining in most tissues; cell type varies (HPA tissue IHC) | |
| Antigen retrieval | Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A30648) | |
| Positive control | Adrenal gland+4 more · see all | |
| 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 | Breast adipocytes stain; adipose adipocytes do not (HPA tissue IHC) | |
| Regulation | S-phase role; expression trend unreported (UniProt) | |
| Isoform / epitope | No isoforms annotated; one 1–420 chain (UniProt) |
Section 1
Recommended PRIM1 IHC & IF Protocols
Compare the catalog antibody's IHC-P protocol (datasheet A30648) with published PRIM1 staining conditions for human liver and mouse specimens (PMC7903777).
| Sample | Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A30648) |
| Fixation | Image fixative and duration unreported (datasheet A30648); verify before use. |
| Sectioning | 4–5 µm sections on charged slides (standard) |
| Deparaffinisation | Xylene, graded ethanol series to water (standard) |
| Antigen retrieval | Heat retrieval: Tris-EDTA pH 9.0 (datasheet A30648); 20 min, 95–100 °C (standard) |
| 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-PRIM1, 1:100 - 1:300 (datasheet A30648) |
| 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 | PRIM1-positive staining in glandular cells of adrenal gland (HPA tissue IHC: Medium). HPA tissue profile: Cytoplasmic expression in most tissues. No signal in the no-primary control. |
💡Decision noteStart with heat-mediated Tris-EDTA retrieval at pH 9.0 for the catalog antibody (datasheet A30648). The published protocol does not specify retrieval (PMC7903777).
Section 2
What Is the Expected PRIM1 Staining Pattern?
Expect predominantly cytoplasmic PRIM1 staining in many tissues, including glandular cells in colon and hematopoietic cells in bone marrow, where HPA reports medium signal (HPA tissue IHC: cytoplasmic profile; medium staining). PRIM1 has no transmembrane segment (UniProt P49642 topology). Treat this as a provisional pattern: the tissue IHC assessment is Uncertain and awaits external verification (HPA tissue IHC: reliability).
| Cytoplasmic staining in colon glandular cells or bone marrow hematopoietic cells. | This fits the reported compartment and medium staining in those cell populations (HPA tissue IHC: cytoplasmic profile; colon and bone marrow). Compare cells within the section before scoring intensity; the HPA pattern is provisional because its reliability is Uncertain (HPA tissue IHC: reliability). |
| Strong nuclear-only staining, with little or no cytoplasmic signal. | Flag a possible localisation artefact and check controls before calling it PRIM1: HPA describes predominantly cytoplasmic tissue staining, while UniProt supplies no subcellular annotation (HPA tissue IHC: profile; UniProt P49642 subcellular record). PRIM1's role in DNA synthesis alone does not validate a nuclear-only IHC pattern (UniProt P49642 function). |
| Strong staining confined to a cell population reported as undetected, such as parathyroid glandular cells. | Consider antibody cross-reactivity or endogenous detection activity, then compare a control section and the expected cell population (HPA tissue IHC: parathyroid glandular cells not detected; general IHC practice). An HPA nondetection is a comparison point, not proof that every specimen must be negative (HPA tissue IHC: Uncertain reliability). |
| Diffuse color across cells, stroma, and blank areas, obscuring cell boundaries. | Treat the pattern as background until controls support a cellular signal; widespread deposit does not match HPA's cell-level cytoplasmic profile (HPA tissue IHC: profile). Inspect background on a section processed without primary antibody and review blocking, washes, and chromogen development (general chromogenic IHC practice). |
| No signal in a section expected to contain positive cells. | First confirm that the section contains the relevant cells: HPA reports medium staining in colon glandular cells and bone marrow hematopoietic cells (HPA tissue IHC: positive cells). If they are present, review antibody and detection controls before interpreting the blank section; the reference pattern remains Uncertain (HPA tissue IHC: reliability; general IHC practice). |
💡Expected PRIM1 appearanceA provisional positive result is discernible cytoplasmic, approximately medium-intensity staining in the specified colon glandular or bone marrow hematopoietic cells; nuclear-only staining or diffuse deposit warrants control review (HPA tissue IHC: profile, positive cells, Uncertain reliability; general IHC practice).
| Tissue and cell population | Expected staining depends on the sampled cells: HPA reports medium signal in colon glandular cells and bone marrow hematopoietic cells, low signal in lung alveolar cells, and no detected signal in parathyroid glandular cells (HPA tissue IHC: cell-level observations). Choose comparison areas by cell identity rather than whole-organ color (general IHC practice). |
| Confidence in the reference pattern | The tissue IHC assessment is Uncertain and pending external verification; the listed rabbit polyclonal antibody, HPA040010, also has Uncertain IHC status (HPA tissue IHC: reliability; HPA antibody validation). Use the reported pattern as a guide for controls, not as an independently established specificity standard (HPA: Uncertain assessments). |
| Protein architecture and cell cycle | PRIM1 is a 420-amino-acid chain without a signal peptide or transmembrane segment, and UniProt lists no isoforms (UniProt P49642 processing, topology, isoforms). HPA notes that transcript variation correlates with the cell cycle, which may inform comparisons between cell populations but does not establish a tissue IHC intensity rule (HPA subcellular summary). |
| IF/ICC Q&A: Is a distinct PRIM1 compartment established for fluorescence images? | No: HPA lists no main subcellular location and no cell lines with ICC-IF images (HPA subcellular record). Its cytoplasmic profile comes from tissue IHC, so verify any fluorescence localisation with assay controls rather than treating that profile as an independently confirmed IF pattern (HPA tissue IHC: profile; general IF practice). |
| Situation | Likely cause | Next action |
|---|---|---|
| Colon glandular cells or bone marrow hematopoietic cells appear blank. | The relevant cells may be absent from the viewed area, or the IHC run may have failed; both are checks to make before interpreting a blank slide (HPA tissue IHC: reported positive cells; general IHC practice). | Confirm cell identity and morphology, then review a known-performing positive control, primary-antibody step, detection reagents, and development (general chromogenic IHC practice). Do not infer PRIM1-specific fixation sensitivity; none is reported in the supplied UniProt or HPA records. |
| Every compartment shows diffuse brown staining. | Nonspecific background or excessive chromogen development is possible when color lacks a cell-defined distribution (general chromogenic IHC practice); HPA reports a cytoplasmic cellular profile (HPA tissue IHC: profile). | Compare the section processed without primary antibody; check blocking, wash adequacy, and development time, then reassess whether cytoplasmic cell staining remains distinguishable (general chromogenic IHC practice). |
| The section shows only nuclear staining. | That localisation conflicts with the predominantly cytoplasmic tissue IHC profile; UniProt does not annotate a definitive PRIM1 compartment (HPA tissue IHC: profile; UniProt P49642 subcellular record). | Check the negative control, morphology, and staining in reported positive cell populations before scoring; record a persistent nuclear-only result as discordant with the provisional HPA pattern (general IHC practice; HPA tissue IHC: Uncertain reliability). |
| Parathyroid glandular cells stain strongly. | HPA lists these cells as not detected, so cross-reactivity or endogenous detection activity is plausible; HPA's tissue assessment is Uncertain (HPA tissue IHC: parathyroid glandular cells, reliability; general IHC practice). | Compare a section without primary antibody and a reported positive cell population; inspect endogenous detection activity using controls appropriate to the chosen detection chemistry (general chromogenic IHC practice). |
| A low-signal sample is scored as negative. | HPA lists low staining in lung alveolar cells and several other populations, so faint cell-associated color can be difficult to distinguish from background (HPA tissue IHC: low observations; general IHC practice). | Score identified cells against background and a control on the same run; report an equivocal result if the signal cannot be separated reliably (general IHC scoring practice). |
| Different tissues give apparently conflicting results. | HPA reports medium staining in breast adipocytes but no detected staining in adipocytes from adipose tissue, illustrating variation in its sampled contexts (HPA tissue IHC: breast and adipose tissue). | Record tissue and cell identity for each slide and compare each observation with its matching HPA entry; avoid treating one tissue's result as a universal adipocyte expectation (HPA tissue IHC: cell-level observations). |
Experiment evidence
IHC & IF images showing PRIM1 staining
A30648 · IHCImmunohistochemical analysis of paraffin-embedded human tonsil. 1, Antibody was diluted at 1:200(4° overnight). 2, Tris-EDTA,pH9.0 was used
A09694-2 · IHCImmunohistochemistry (IHC) analyzes of PRIM1 (K413) pAb in paraffin-embedded human breast carcinoma tissue at 1:100.
HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000198056-PRIM1/tissue/cerebral+cortex#imid_11651815
HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000198056-PRIM1/tissue/colon#imid_11651741
HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000198056-PRIM1/tissue/liver#imid_11651742
HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000198056-PRIM1/tissue/kidney#imid_11651759
← swipe / scroll for more images →
Real IHC / IF data behind the staining-pattern expectations in this section.
Sample controls for PRIM1 IHC & IF
🧪Run appendix first: glandular cells should stain at a Medium level (HPA: appendix glandular cells, Medium). Use caudate glial cells as the negative tissue (HPA: caudate glial cells, Not detected); on the appendix slide, compare non-glandular stromal cells as a background reference only if they are unstained, since their PRIM1 status is not specified by HPA.
Positive control tissue: Adrenal gland (Glandular cells, HPA Medium)
Negative control tissue: Adipose tissue (HPA Not detected)
ICC-IF cell lines (HPA subcellular resource): HPA carries no ICC-IF cell line for PRIM1; derive a cell-line control from the positive tissue's cell type (Glandular cells) and confirm it by RNA or western blot first.
Technical controls: Include a no-primary, secondary-only control and an irrelevant primary matched to the catalog antibody’s host species and immunoglobulin class; use PRIM1 knockout material or a validated immunogen peptide block as a biological specificity control (standard IHC practice). For chromogenic IHC, quench endogenous peroxidase and inspect the appendix slide for residual background before scoring glandular cells (standard IHC practice).
⚠️Feasibility: A target-specific fixation window or fixation effect is unreported, and the fixative in the selected SKU A30648 paraffin-section caption is unreported (datasheet: paraffin-embedded tonsil caption; fixative not stated). That caption uses Tris-EDTA at pH 9.0 for retrieval, but does not establish that PRIM1 staining depends on retrieval in appendix (datasheet: SKU A30648 caption). Frozen sections or IF cannot be judged easier from these data; IF needs separate validation, including an autofluorescence control, because HPA supplies no PRIM1 ICC-IF image cell lines (HPA: PRIM1 subcellular record).
HPA tissue IHC evidence for PRIM1
Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Pending external verification.). 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 |
|---|---|---|---|---|
| Adrenal gland | Glandular cells | Medium | Protein (IHC) | HPA → |
| Appendix | Glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | Hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Breast | Adipocytes | Medium | Protein (IHC) | HPA → |
| Bronchus | Respiratory epithelial cells | Medium | Protein (IHC) | HPA → |
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adipose tissue | Adipocytes | Not detected | Protein (IHC) | HPA → |
| Caudate | Glial cells | Not detected | Protein (IHC) | HPA → |
| Cerebellum | Cells in granular layer | Not detected | Protein (IHC) | HPA → |
| Hippocampus | Glial cells | Not detected | Protein (IHC) | HPA → |
| Lymph node | Germinal center cells | Not detected | Protein (IHC) | HPA → |
Section 3
Advanced PRIM1 IHC Tips
Use the catalog antibody’s paraffin section result as a starting point, and interpret PRIM1 staining cautiously because the reported tissue pattern awaits external verification (caption A30648; HPA reliability).
Which retrieval condition should I start with for PRIM1 paraffin section IHC?
Start with heat-mediated Tris-EDTA retrieval at pH 9.0 for paraffin sections (datasheet A30648). The documented human tonsil image used primary antibody at 1:200 overnight at 4 °C, followed by secondary antibody at 1:200 for 45 min at room temperature (caption A30648). If staining is weak, vary heating and cooling while keeping the buffer, antibody dilution and detection conditions fixed; examine adjacent sections for tissue damage or increased background (standard IHC practice). If signal remains weak, compare an alternative retrieval buffer on matched sections, treating pH 9.0 as the documented starting condition (caption A30648; standard IHC practice).
How should I troubleshoot weak staining when the tissue fixative is unknown?
The human tonsil caption describes paraffin embedding but does not state a fixative, so PRIM1 specific sensitivity to fixation is unknown (caption A30648). Record the actual fixative and fixation duration for each specimen before comparing staining across blocks (standard IHC practice). On serial sections, hold retrieval at Tris-EDTA pH 9.0 and primary dilution at 1:200 while checking section integrity and background (datasheet A30648; caption A30648; standard IHC practice). If blocks differ in signal, assess processing history and technical controls before assigning the difference to PRIM1 abundance; tissue expression reports do not establish a fixation effect (standard IHC practice; HPA tissue IHC).
Should PRIM1 stain nuclei or cytoplasm in paraffin sections?
Score nuclear and cytoplasmic staining separately: UniProt provides no PRIM1 subcellular annotation, while HPA describes cytoplasmic expression in most tissues with uncertain IHC reliability (UniProt P49642; HPA tissue IHC). PRIM1 participates in DNA synthesis initiation at replicative forks during S phase, but that function alone does not establish an exclusive compartment for the observed IHC signal (UniProt P49642 function). Its sequence has no transmembrane segment, so a sharp plasma membrane outline needs independent validation before interpretation as PRIM1 (UniProt P49642 topology; standard IHC practice). Compare staining with the same tissue’s negative reagent control and assess whether the pattern follows intact cells rather than section edges (standard IHC practice).
Could isoforms or processing explain inconsistent PRIM1 staining?
The supplied UniProt record lists 0 isoforms and one chain spanning residues 1–420, with no signal peptide or propeptide (UniProt P49642 processing; UniProt P49642 isoforms). It lists no glycosylation sites and reports N terminal acetylmethionine at residue 1, but the antibody epitope is not supplied (UniProt P49642 glycosylation; UniProt P49642 modified residues; caption A30648). Consequently, do not attribute staining differences to a particular splice form or masked terminal epitope without antibody mapping evidence (UniProt P49642 isoforms; standard IHC practice). Compare serial sections under identical retrieval and antibody conditions, and use an independent PRIM1 antibody with a known epitope if available (standard IHC practice).
How can I assess PRIM1 by IF alongside a cell identity marker?
Treat IF as a separately optimized application: the supplied catalog image documents paraffin section chromogenic IHC, while HPA lists no cell lines with PRIM1 ICC/IF images (caption A30648; HPA subcellular). Multiplex with a validated marker identifying the cell population under study, using distinct fluorophores and single stain controls to check bleed through (standard IF practice). Select fluorophores whose signal separates from the specimen’s autofluorescence, and include an unstained section to assess that background (standard IF practice). PRIM1 lacks a transmembrane segment; permeabilize for intracellular access, but optimize detergent exposure because the antibody’s epitope location is unspecified (UniProt P49642 topology; standard IF practice).
How do I separate PRIM1 signal from chromogenic background?
Run a no primary control and inspect tissue edges, pigment and necrotic areas before interpreting brown deposit as PRIM1 (standard IHC practice). Use a peroxidase block and monitor DAB development when using peroxidase detection; these are general chromogenic workflow steps, not evidence of PRIM1 expression (standard IHC practice). If diffuse staining persists, compare a primary antibody titration around the documented 1:200 dilution while holding retrieval at Tris-EDTA pH 9.0 (caption A30648; datasheet A30648; standard IHC practice). Assess whether blocking, washes or secondary reagent controls reduce background without erasing structured cellular staining (standard IHC practice).
What is a defensible way to quantify PRIM1 IHC? ⚠ ANSWER MARKED FOR VERIFICATION
Define the cell population and compartment before scoring, since HPA reports mainly cytoplasmic tissue staining but rates its IHC reliability uncertain (HPA tissue IHC). For an H-score, record percentages at intensity grades 0–3 and calculate the sum of percentage times grade; also report the percentage of positive cells (standard IHC practice). If counting positive cells, report density per mm² of viable tissue and exclude folds, necrosis and section edges by a prespecified rule (standard IHC practice). Normalize comparisons to the same eligible cell population, tissue area and staining batch, using matched negative controls and fixed thresholds across specimens (standard IHC practice).
When is a PRIM1 positive stain convincing rather than artefactual?
A convincing result shows reproducible staining in intact cells above the matched negative control, without concentration at section edges or necrotic zones (standard IHC practice). Compare the stained cell type with the specimen’s anatomy: HPA reports medium staining in bone marrow hematopoietic cells and colon glandular cells, but rates its IHC reliability uncertain (HPA tissue IHC). HPA describes mainly cytoplasmic staining, while UniProt gives no subcellular annotation; an isolated sharp membrane pattern is questionable because PRIM1 has no transmembrane segment (HPA tissue IHC; UniProt P49642 subcellular; UniProt P49642 topology). Check endogenous peroxidase and pigment before interpreting DAB, and confirm unexpected patterns with an independent specificity control (standard IHC practice).
Boster reagents
Best PRIM1 / DNA primase small subunit IHC Antibodies
Two anti-PRIM1 antibodies have paraffin-section IHC images from human tissue (catalog IHC captions); both list human, mouse and rat reactivity (catalog reactivity), while A30648 also lists IF/ICC (catalog applications).
Real IHC data
Anti-DNA primase small subunit PRIM1 Antibody
Cat # A30648
Real IHC data
Anti-PRIM1 (K413) Antibody
Cat # A09694-2
A30648 will render with IHC data from paraffin-embedded human tonsil (A30648 IHC caption); its listed applications include IF and ICC (A30648 catalog applications), but no IF image is supplied (A30648 catalog images). A09694-2 will render with IHC data from paraffin-embedded human breast carcinoma (A09694-2 IHC caption); IHC is listed, but IF/ICC is not (A09694-2 catalog applications).
Which to pick: For tissue IHC, choose A30648 if you want an image caption documenting Tris-EDTA retrieval at pH 9.0 and a 1:200 primary dilution (A30648 IHC caption); A09694-2 also has paraffin-section IHC data at 1:100 (A09694-2 IHC caption). For IF/ICC, choose A30648 because those applications are listed for it (A30648 catalog applications); both antibodies are rabbit polyclonals listing human, mouse and rat reactivity, so either is a cross-species IHC candidate (catalog host, clonality, reactivity and applications). Both image captions identify paraffin-embedded tissue, but neither reports the fixative (A30648 and A09694-2 IHC captions).
Each figure is that product's own IHC / IF validation image from its datasheet.
References
- UniProt Consortium. UniProt entry P49642 (PRI1_HUMAN, DNA primase small subunit).
- Human Protein Atlas. PRIM1 tissue IHC expression (reliability: Uncertain).
- Human Protein Atlas. PRIM1 subcellular location (ICC-IF): Variation in transcript expression is correlated to the cell cycle..
- Human Protein Atlas. PRIM1 antibody validation summary (1 antibodies).
- DNA primase subunit 1 deteriorated progression of hepatocellular carcinoma by activating AKT/mTOR signaling and UBE2C-mediated P53 ubiquitination. Cell & bioscience 2021 — PMC7903777.
- Targeting Bone Tumours with 45S5 Bioactive Glass. International journal of molecular sciences 2024 — PMC11477169.
- Association between elevated PRIM1 expression and poor prognosis in human urothelial carcinoma. Journal of Taibah University Medical Sciences 2026 — PMC12809060.
- Optimization of the chicken chorioallantoic membrane assay as reliable in vivo model for the analysis of osteosarcoma. PloS one 2019 — PMC6464229.
- PubMed PMID:8026492 — UniProt-cited evidence.
- PubMed PMID:15489334 — UniProt-cited evidence.
- PubMed PMID:9268648 — UniProt-cited evidence.
Immunohistochemistry protocol sheet for PRIM1 (DNA primase small subunit). Expected localisation Cytoplasmic staining reported; reliability uncertain (HPA tissue IHC). Antigen retrieval: Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A30648). Validated IHC antibody: A30648 at 1:100 - 1:300 (the product's own IHC validation image is shown). Controls (HPA): positive Adrenal gland (Glandular cells); negative Adipose tissue. IHC workflow; specimen preparation unspecified. Protocol steps: 1. Sample: Paraffin-embedded human tonsil tissue; fixative not specified (datasheet A30648); 2. Fixation: Image fixative and duration unreported (datasheet A30648); 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: Tris-EDTA pH 9.0 (datasheet A30648); 20 min, 95–100 °C (standard); 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-PRIM1, 1:100 - 1:300 (datasheet A30648); 9. Primary incubation: Overnight at 4 °C (standard). Watch for: Fixation: Keep fixation consistent across sections. (standard IHC practice; not target-specific); Caveat: Breast adipocytes stain; adipose adipocytes do not (HPA tissue IHC); Isoform / epitope: No isoforms annotated; one 1–420 chain (UniProt); Regulation: S-phase role; expression trend unreported (UniProt). Evidence: UniProt P49642, HPA tissue IHC · Uncertain, HPA cell-line RNA · Variation in transcript expression is correlated to the cell cycle., Datasheet A30648, PMC7903777. QR code links to https://www.bosterbio.com/bosterbio-gene-info-cards/PRIM1/immunohistochemistry-ihc-guide.