ZNF668 / Zinc finger protein 668 · IHC design guide

Design Immunohistochemistry for ZNF668

Plan chromogenic ZNF668 IHC in paraffin sections using the catalog antibody’s 1:100–1:300 dilution range (datasheet A13922-1). Assess nuclear staining against the reported all-tissue profile, whose reliability is uncertain (HPA tissue IHC).

Evidence assembled Oct 2026 · For research use; verify linked source records and product datasheet before use

Immunohistochemistry protocol sheet for ZNF668 (IHC for ZNF668): expected localisation Nuclear tissue staining reported; reliability uncertain (HPA tissue IHC), antibody A13922-1, validated IHC image, and IHC protocol steps — Printable **ZNF668** IHC protocol sheet — expected localisation Nuclear tissue staining reported; reliability uncertain (HPA tissue IHC), antibody A13922-1, controls and protocol steps. Open the full ZNF668 IHC guide →

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ZNF668 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 tissue staining reported; reliability uncertain (HPA tissue IHC)
	Staining pattern	Nuclear staining across all tissues (HPA tissue IHC)
	Antigen retrieval	Tris-EDTA pH 9.0 HIER, heat-mediated (datasheet A13922-1)
	Positive control ⓘ	Adrenal gland+4 more · see all
	Negative control ⓘ	None in HPA (detected in all 45 tissues); use no-primary + isotype controls

Important caveats

Reasons your staining may differ from the expected pattern.

	Fixation	Keep fixation consistent across sections (standard IHC practice; not target-specific)
	Caveat	Staining awaits external verification (HPA tissue IHC)
	Regulation	No expression regulator annotated (UniProt)
	Isoform / epitope	2 isoforms; epitope coverage unreported (UniProt)

Section 1

Recommended ZNF668 IHC & IF Protocols

The catalog antibody’s IHC-P protocol (datasheet: A13922-1) is accompanied by a published ZNF668 protocol for a multi-tumor tissue microarray (PMC12732025).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	Paraffin-embedded human brain tumor tissue; fixative not specified (datasheet A13922-1)
Fixation	Image fixative and duration unreported (datasheet A13922-1); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat retrieval: Tris-EDTA pH 9.0 (datasheet A13922-1); 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-ZNF668, 1:100-1:300 (datasheet A13922-1)
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	ZNF668-positive staining in glandular cells of adrenal gland (HPA tissue IHC: High). HPA tissue profile: Nuclear expression in all tissues. No signal in the no-primary control.

💡Decision noteStart with heat-mediated Tris-EDTA at pH 9.0 for the catalog antibody (datasheet: A13922-1); the published protocol used high-pressure EDTA at pH 9.0 (PMC12732025).

Section 2

What Is the Expected ZNF668 Staining Pattern?

ZNF668 is a nuclear protein with no annotated transmembrane segment (UniProt Q96K58: subcellular location and topology). In paraffin-section IHC, expect nuclear staining across tissues, including glandular cells in colon and respiratory epithelial cells in bronchus (HPA: tissue IHC). Treat intensity as provisional: HPA rates the tissue profile Uncertain because antibody staining and RNA expression show medium consistency, pending external verification (HPA: tissue IHC reliability).

What am I looking at on my slide?
Clear nuclear chromogen in colon glandular cells or bronchial respiratory epithelial cells.	This matches reported High staining in those cells (HPA: colon and bronchus tissue IHC) and the nuclear location (UniProt Q96K58). Record the cell type and nuclear fraction stained; HPA's tissue assessment remains Uncertain (HPA: reliability).
Strong cytoplasmic or membrane staining with little nuclear signal.	The compartment conflicts with the nuclear annotation and lack of a transmembrane segment (UniProt Q96K58). Treat it as a suspected artefact; assess background, detection controls and whether nuclear staining is present before interpreting it as ZNF668.
The strongest signal appears in a cell population reported as Low, while an expected High population is faint.	For example, prominent hepatocyte staining alongside faint colon glandular staining conflicts with HPA's relative levels (HPA: liver Low; colon High). Consider cross-reactivity or endogenous detection activity (standard IHC practice), while allowing for HPA's Uncertain reliability.
Chromogen spreads across nuclei, cytoplasm and spaces between cells.	A diffuse deposit cannot establish nuclear localisation (UniProt Q96K58: nucleus). Check blocking, wash and detection controls for nonspecific background (standard IHC practice); score discrete cellular signal only after the background is resolved.
No nuclear signal in a section containing colon glandular cells.	Colon glandular cells are reported High (HPA: colon tissue IHC), so an absent signal calls for a control and workflow check. It does not by itself prove ZNF668 is absent, especially given the Uncertain tissue assessment (HPA: reliability).

💡Expected ZNF668 appearanceCall a section positive when chromogen is predominantly nuclear in identifiable cells, with conspicuous signal in a reported High population such as colon glandular cells (UniProt Q96K58: nucleus; HPA: colon High); diffuse extracellular or dominant cytoplasmic colour is suspect (standard IHC practice).

How each factor affects the staining
Tissue and cell selection	Colon glandular cells, bronchial respiratory epithelial cells and bone marrow hematopoietic cells are reported High; hepatocytes and adipocytes are Low (HPA: tissue IHC). Use these as relative comparisons, not as absolute positive or negative standards (HPA: reliability Uncertain).
Compartment resolution	Nuclear staining is the tissue-level expectation (HPA: nuclear expression in all tissues; UniProt Q96K58: nucleus). A chromogenic IHC section need not resolve the nucleolar detail reported by ICC-IF (HPA: subcellular ICC-IF); evaluate the nucleus first.
Antibody evidence	The listed antibody HPA043048 has Uncertain IHC status and Approved ICC status (HPA: antibody validation). The tissue profile also awaits external verification (HPA: reliability). Agreement with the expected pattern supports interpretation but does not independently establish specificity.
Isoforms and processing	UniProt lists two isoforms and annotates one chain spanning residues 1–619, with no signal peptide or propeptide (UniProt Q96K58). The payload gives no epitope position or isoform coverage, so staining cannot identify which isoform contributed.
IF/ICC Q&A: What subnuclear pattern is expected?	HPA reports mainly nucleoli and nucleoli rim, with additional nucleoplasm, in ICC-IF images from A-431, U-251MG and U2OS (HPA: subcellular ICC-IF). That approved ICC observation guides image interpretation; it does not prescribe an IHC protocol or guarantee visible nucleoli in chromogenic sections.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
No staining in colon glandular cells.	A missed or weak detection step is possible (standard IHC practice); colon glandular cells are reported High (HPA: colon tissue IHC).	Check the catalog antibody's IHC-P conditions, detection reagents and a concurrently processed positive section (standard IHC practice). Interpret a persistent absence cautiously because tissue IHC reliability is Uncertain (HPA: reliability).
Only cytoplasmic signal is visible.	The location conflicts with ZNF668's nuclear annotation (UniProt Q96K58); nonspecific or endogenous detection signal is possible (standard IHC practice).	Compare a detection-only control and inspect nuclear counterstain alignment (standard IHC practice). Do not score cytoplasmic colour alone as a positive ZNF668 result.
Colour covers the whole section.	Diffuse background can obscure the expected nuclear pattern (UniProt Q96K58: nucleus; standard IHC practice).	Review blocking, washes and detection-only controls, then reassess whether discrete nuclei remain above background (standard IHC practice). Avoid assigning a cell type from a uniform deposit.
Hepatocytes stain more strongly than colon glandular cells.	This reverses the supplied relative profile (HPA: hepatocytes Low; colon glandular cells High), although HPA rates the tissue IHC profile Uncertain.	Review cell identification and section controls; investigate cross-reactivity or endogenous detection activity (standard IHC practice). Report the discrepancy rather than treating HPA levels as an absolute exclusion rule.
Nuclei stain, but nucleoli cannot be distinguished.	Nucleoli and nucleoli rim are ICC-IF findings (HPA: subcellular ICC-IF); chromogenic tissue IHC may not resolve that detail (standard IHC practice).	Judge the IHC result by nuclear localisation and the identified cell population (UniProt Q96K58: nucleus; HPA: tissue IHC). Use the separate IF/ICC guide for subnuclear imaging.
A section shows patchy or unexpectedly weak nuclear staining.	The supplied sources do not establish a ZNF668-specific fixation sensitivity; variable detection is a general IHC possibility (standard IHC practice).	Compare sections processed together and review the catalog antibody's IHC-P conditions (standard IHC practice). Document the variation without assigning it to ZNF668 epitope masking.

Source: UniProt Q96K58 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing ZNF668 staining

Immunohistochemical analysis of paraffin-embedded human brain tumor. 1, Antibody was diluted at 1:200 (4° overnight). 2, Tris-EDTA, pH9.0 was used for antigen retrieval. 3, Secondary antibody was diluted at 1:200 (room temperature, 45min).

A13922-1 · IHCImmunohistochemical analysis of paraffin-embedded human brain tumor. 1, Antibody was diluted at 1:200 (4° overnight). 2, Tris-EDTA, pH9.0 wa

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000167394-ZNF668/tissue/cerebral+cortex#imid_12129807

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000167394-ZNF668/tissue/colon#imid_12129725

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000167394-ZNF668/tissue/liver#imid_12129718

HPA · KidneyHuman Protein Atlas IHC, Kidney. Source: https://www.proteinatlas.org/ENSG00000167394-ZNF668/tissue/kidney#imid_12129719

HPA · ICC-IF A-431Human Protein Atlas immunofluorescence, A-431, antibody HPA043048; green = ZNF668, blue = nucleus, red = microtubules.

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Real IHC / IF data behind the staining-pattern expectations in this section.

Sample controls for ZNF668 IHC & IF

🧪Run colon first; its glandular cells should show nuclear staining (HPA: High in colon glandular cells; UniProt Q96K58: nucleus). HPA detects ZNF668 in all 45 scored tissues, so there is no validated negative tissue; use no-primary and isotype controls, and do not designate other cells on the positive slide as internal negatives solely because their nuclei stain less strongly (HPA: no negative tissue rows; standard IHC interpretation).

Positive control tissue: Adrenal gland (Glandular cells, HPA High)

Negative control tissue: None in HPA: ZNF668 is detected in all 45 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 ZNF668 in A-431, U-251MG, U2OS, with annotated localisation: Nucleoli (approved), Nucleoli rim (approved) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control and an isotype control matched to the primary antibody’s host species and clonality; confirm specificity with ZNF668 knockout material or a peptide-block control if an appropriate immunizing peptide is available (standard IHC practice). For colon sections, block endogenous peroxidase when using peroxidase detection and assess mucin-associated background (standard IHC practice).

⚠️Feasibility: No target-specific fixation window or fixation effect is reported in the supplied evidence, and the selected A13922-1 tissue-IHC caption does not state a fixative (selected A13922-1 caption). The paraffin-section caption uses Tris-EDTA at pH 9.0 for retrieval and a 1:200 primary antibody dilution overnight at 4°C; it does not establish whether that retrieval condition is required (selected A13922-1 caption). The supplied evidence does not establish that frozen sections or IF are easier than paraffin IHC; colon mucin can complicate background assessment (HPA: colon glandular cells High; standard IHC practice).

HPA tissue IHC evidence for ZNF668

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Uncertain — Medium consistency between antibody staining and RNA expression data. 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	High	Protein (IHC)	HPA →
Bone marrow	Hematopoietic cells	High	Protein (IHC)	HPA →
Bronchus	Respiratory epithelial cells	High	Protein (IHC)	HPA →
Cervix	Glandular cells	High	Protein (IHC)	HPA →
Colon	Glandular cells	High	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
None in HPA: ZNF668 is detected in all 45 scored tissues. Use a no-primary (secondary-only) and an isotype control instead.

Section 3

Advanced ZNF668 IHC Tips

Troubleshoot ZNF668 staining by checking nuclear localization, documented retrieval conditions, and controls before interpreting chromogenic signal.

Which retrieval condition should I use when ZNF668 nuclear staining is weak?

Start with heat-mediated Tris-EDTA retrieval at pH 9.0 for paraffin sections (datasheet A13922-1). The catalog image used this retrieval before staining paraffin-embedded human brain tumor with primary antibody at 1:200 overnight at 4°C (caption A13922-1). If staining remains weak, compare retrieval runs on adjacent sections while holding antibody dilution, detection, and imaging conditions constant. Examine tissue morphology and nonspecific staining alongside nuclear signal; stronger color alone does not establish better retrieval. Record heating and cooling conditions so that any improvement can be repeated, and judge it against the same positive and negative controls.

Could fixation explain weak ZNF668 staining in my paraffin sections?

Target-specific fixation sensitivity is unknown: the selected paraffin-section caption does not state a fixative (caption A13922-1). Record the specimen’s actual fixative and fixation duration, then compare sections processed with documented conditions using the same retrieval and staining run. As a general IHC check, inspect morphology for poor preservation and compare signal in well-preserved areas before changing antibody concentration. Keep Tris-EDTA at pH 9.0 as the documented retrieval starting point (datasheet A13922-1). Do not assign weak staining to fixation alone when retrieval variation, detection performance, or loss of tissue integrity could also account for it.

What staining pattern should count as plausible ZNF668 in tissue?

Prioritize staining within intact nuclei because ZNF668 is annotated as nuclear (UniProt Q96K58), and HPA reports nuclear expression across tissues (HPA tissue IHC). At higher resolution, nucleolar and nucleolar-rim enrichment is plausible, with additional nucleoplasmic localization reported in cell imaging (HPA subcellular). Chromogenic sections may not resolve those subnuclear boundaries consistently, so score nuclear staining without requiring a visible rim. Review cell identity and section quality before treating cytoplasmic or diffuse extracellular color as positive. Compare the candidate signal with a negative control and with nearby well-preserved cells under the same detection conditions.

How should I investigate inconsistent staining across ZNF668 isoforms?

ZNF668 has 2 listed isoforms, so first check which sequence and epitope the antibody documentation covers (UniProt Q96K58: isoforms 1 and 2). Its annotated chain spans residues 1–619, with no transmembrane segment or signal peptide (UniProt Q96K58). Acetylation at residue 1 and phosphorylation at residues 10 and 387 are recorded modifications, but their effects on this antibody’s tissue staining are unestablished (UniProt Q96K58). Map the immunogen against both isoforms if its sequence is available. If it is unavailable, report staining as antibody-detected ZNF668 signal without assigning an isoform or modification state.

How can I adapt the ZNF668 question to a multiplex IF experiment?

Use IF as a separate validation experiment: the paraffin-section image documents chromogenic tissue staining, not IF performance (caption A13922-1). For a colon section, pair ZNF668 with an epithelial marker to identify glandular cells, which HPA reports as strongly stained (HPA tissue IHC: colon). Choose a fluorophore channel after inspecting tissue autofluorescence and include single-color controls to assess bleed-through. Because ZNF668 is nuclear and has no transmembrane segment, optimize permeabilization for access to an intracellular nuclear epitope while preserving nuclear structure (UniProt Q96K58). Compare nuclear signal with a no-primary control before interpreting apparent nucleolar enrichment (HPA subcellular: nucleoli and nucleoli rim).

How do I reduce diffuse color without losing nuclear ZNF668 signal?

First compare the stained section with a no-primary control and inspect whether unwanted color follows tissue edges, damaged areas, or endogenous pigment. Apply an appropriate protein block and, for peroxidase-based detection, an endogenous peroxidase block as general chromogenic IHC steps. The selected paraffin-section image used primary antibody at 1:200 overnight at 4°C and secondary antibody at 1:200 for 45 minutes at room temperature (caption A13922-1). If background persists, adjust blocking, washing, or antibody concentration one variable at a time. Preserve a readable nuclear counterstain so that brown signal can be assigned to cells.

What is a defensible way to quantify ZNF668 chromogenic staining? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and tissue region before scoring, and count only signal assigned to intact nuclei because ZNF668 is annotated as nuclear (UniProt Q96K58). Report the percentage of positive nuclei and, when intensity is reproducibly separable, an H-score with its stated intensity categories. For heterogeneous specimens, also report positive nuclear density per mm² of viable tissue and normalize comparisons to the number of evaluable nuclei or viable area. Keep retrieval, detection, counterstaining, exposure, and threshold rules consistent across slides. Document excluded necrotic regions and check scorer agreement before interpreting small differences as biological changes.

How can I distinguish genuine ZNF668 staining from an artefact?

A credible result assigns signal to intact nuclei in an appropriate cell population: ZNF668 is nuclear (UniProt Q96K58), and HPA reports nuclear tissue staining with uncertain reliability (HPA tissue IHC). Check whether high staining in colon glandular cells or bronchial respiratory epithelial cells is reproduced before using either as a reference pattern (HPA tissue IHC). Reject color concentrated at section edges, in necrosis, or outside cells as evidence on its own. Use a no-primary control to expose detection background, including residual endogenous enzyme activity in peroxidase-based staining. Interpret discordant compartments or cell populations cautiously and seek independent corroboration before making a target-specific claim.

Boster reagents

Best ZNF668 / Zinc finger protein 668 IHC Antibodies

A13922-1 is listed for human and mouse IHC and IF (catalog: applications and reactivity); its supplied image documents IHC on paraffin-embedded human brain tumor (IHC image caption).

Real IHC data Immunohistochemical analysis of paraffin-embedded human brain tumor. 1, Antibody was diluted at 1:200 (4° overnight). 2, Tris-EDTA, pH9.0 was used for antigen retrieval. 3, Secondary antibody was diluted at 1:200 (room temperature, 45min).

Anti-Zinc finger protein 668 ZNF668 Antibody

Cat # A13922-1

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A13922-1 will render with its IHC figure from paraffin-embedded human brain tumor (IHC image caption). It is listed for human and mouse IHC and IF, but no IF image is supplied (catalog: applications, reactivity and image captions).

Which to pick: Choose A13922-1 for paraffin-section IHC: its own figure used a 1:200 primary dilution and Tris-EDTA retrieval at pH 9.0 (IHC image caption); the fixative is unreported (IHC image caption). For IF, A13922-1 is listed with a 1:200–1:1000 dilution range, while ICC validation and an IF image are unreported (catalog: applications, dilution and image captions). The same SKU is listed as mouse reactive, but its supplied IHC figure shows human tissue only (catalog: reactivity; IHC image caption).

Each figure is that product's own IHC / IF validation image from its datasheet.

References

UniProt Consortium. UniProt entry Q96K58 (ZN668_HUMAN, Zinc finger protein 668).
Human Protein Atlas. ZNF668 tissue IHC expression (reliability: Uncertain).
Human Protein Atlas. ZNF668 subcellular location (ICC-IF): Mainly localized to the nucleoli and nucleoli rim. In addition localized to the nucleoplasm..
Human Protein Atlas. ZNF668 antibody validation summary (1 antibodies).
Comprehensive Pan-Cancer Analysis of ZNF668 Reveals the Prognostic and Immunological Significance of ZNF668. Current issues in molecular biology 2025 — PMC12732025.
PubMed PMID:14702039 — UniProt-cited evidence.
PubMed PMID:15616553 — UniProt-cited evidence.
PubMed PMID:15489334 — UniProt-cited evidence.