ABCG1 / ATP-binding cassette sub-family G member 1 · IHC design guide

Design Immunohistochemistry for ABCG1

Plan ABCG1 staining in paraffin sections using the observed cytoplasmic tissue pattern, including macrophages (HPA tissue IHC). This guide covers fixation, detection and scoring while accounting for the low agreement between antibody staining and RNA expression (HPA tissue IHC).

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

Immunohistochemistry protocol sheet for ABCG1 (IHC for ABCG1): expected localisation Cytoplasmic tissue staining (HPA tissue IHC); ER/Golgi membrane localisation (UniProt), antibody A01227-1, validated IHC image, and IHC protocol steps — Printable **ABCG1** IHC protocol sheet — expected localisation Cytoplasmic tissue staining (HPA tissue IHC); ER/Golgi membrane localisation (UniProt), antibody A01227-1, controls and protocol steps. Open the full ABCG1 IHC guide →

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ABCG1 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 tissue staining (HPA tissue IHC); ER/Golgi membrane localisation (UniProt)
	Staining pattern	General cytoplasmic staining, including macrophages (HPA tissue IHC)
	Antigen retrieval	Citrate pH 6.0 HIER, 95–98 °C, 20 min (rule: cytoplasmic / membrane antigen)
	Positive control ⓘ	Bronchus+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 formalin fixation consistent across sections. (standard IHC practice; not target-specific)
	Caveat	Low agreement between staining and RNA expression (HPA tissue IHC)
	Regulation	Higher in Tangier disease macrophages (UniProt)
	Isoform / epitope	8 isoforms; check cytoplasmic vs extracellular epitope (UniProt)

Section 1

Recommended ABCG1 IHC & IF Protocols

The catalog antibody’s IHC-P protocol is accompanied by published ABCG1 IHC methods for mouse aortic roots (PMC8510679) and tumor tissue (PMC8425206).

Recommended immunohistochemistry (IHC-P) protocol parameters
Sample	FFPE human hepatocarcinoma tissue (datasheet A01227-1)
Fixation	Image formalin-fixed; duration unreported (datasheet A01227-1); verify before use.
Sectioning	4–5 µm sections on charged slides (standard)
Deparaffinisation	Xylene, graded ethanol series to water (standard)
Antigen retrieval	Heat-induced epitope retrieval in citrate buffer, pH 6.0, 20 min at 95–98 °C (standard rule: cytoplasmic / membrane antigen)
Peroxidase block	3% H2O2, 10 min, room temperature (standard)
Blocking	10% normal serum of the secondary host, 30 min, room temperature (standard)
Primary antibody	Rabbit anti-ABCG1, 1:10-1:50 (datasheet A01227-1)
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	ABCG1-positive staining in ciliated cells (cilia axoneme) of bronchus (HPA tissue IHC: High). HPA tissue profile: General cytoplasmic expression, including macrophages. No signal in the no-primary control.

💡Decision noteStart with citrate pH 6.0 retrieval at 95–98 °C for 20 min (page antigen-retrieval rule).

Section 2

What Is the Expected ABCG1 Staining Pattern?

ABCG1 is predominantly associated with intracellular ER and Golgi membranes, with cell membrane localization also reported; its six transmembrane segments support a membrane-associated pattern (UniProt P45844 topology and subcellular location). In tissue IHC, expect cytoplasmic staining that includes macrophages, with strong staining reported in selected ciliated cells and late spermatids (HPA tissue IHC). Interpret tissue intensity cautiously: HPA rates the IHC profile Approved but reports low consistency with RNA expression (HPA tissue IHC).

What am I looking at on my slide?
Cytoplasmic staining appears in macrophages; ciliated bronchial cells show high axonemal staining (HPA tissue IHC).	This fits the reported tissue profile, while intracellular membrane staining also fits the predominant ER and Golgi localization (HPA tissue IHC; UniProt P45844 subcellular location). Assess the stained cell and compartment together: HPA's Approved profile has low consistency with RNA expression, so intensity alone is weak evidence of specificity (HPA tissue IHC).
The dominant signal is nuclear, although the expected ABCG1 pattern is cytoplasmic or membrane associated (HPA tissue IHC; UniProt P45844 subcellular location).	Treat dominant nuclear staining as suspect and check the counterstain, detection controls and antibody conditions (general IHC practice). Do not reject a cell edge signal solely because it differs from a Golgi-like pattern: cell membrane localization is also reported (UniProt P45844 subcellular location).
Strong staining is confined to adipocytes or prostate glandular cells, both listed as not detected by HPA (HPA tissue IHC).	Check for cross-reactivity or endogenous detection activity with appropriate controls (general IHC practice). These HPA observations are useful comparators, but they are not absolute biological negatives; the tissue IHC profile has low consistency with RNA expression (HPA tissue IHC).
Chromogen covers stroma, lumens or many cell types without a readable cellular pattern (general IHC practice).	Interpret this as background until controls establish a cellular signal (general IHC practice). The reported ABCG1 tissue profile is cytoplasmic and includes macrophages; a diffuse wash across the section cannot establish that pattern (HPA tissue IHC).
No staining appears in ciliated bronchial cells or late spermatids, where HPA reports high staining (HPA tissue IHC).	Check section quality, retrieval, detection reagents and the positive control before calling ABCG1 absent (general IHC practice). HPA's low staining-to-RNA consistency also means a single negative section should be interpreted cautiously (HPA tissue IHC).

💡Expected ABCG1 appearanceCall a result positive when cellular staining follows the reported cytoplasmic pattern, including macrophages, or the high axonemal pattern in ciliated bronchial cells; dominant nuclear or section-wide diffuse color is suspect (HPA tissue IHC; general IHC practice).

How each factor affects the staining
Compartment and epitope location	ABCG1 has 6 transmembrane segments and cytoplasmic and extracellular regions (UniProt P45844 topology). The supplied evidence does not identify the antibody epitope; do not infer its accessibility in paraffin sections from topology alone.
Antigen retrieval	Retrieval conditions can be optimized against a positive tissue and a control section (general IHC practice). No ABCG1-specific retrieval condition or fixation sensitivity is supplied; tissue staining levels do not establish either effect (HPA tissue IHC).
Isoforms	UniProt lists 8 ABCG1 isoforms (UniProt P45844 isoforms). The supplied evidence does not establish which isoforms the IHC-validated antibody recognizes, so a tissue pattern cannot be assigned to one isoform.
Detection chemistry	Endogenous activity can produce chromogen independently of the primary antibody; use detection controls and blocking suited to the chosen chemistry (general IHC practice). Such color is not evidence of ABCG1 localization.
IF/ICC Q: What pattern should I expect?	A: HPA reports mainly Golgi localization, with vesicles marked uncertain, in ICC-IF (HPA subcellular). That observation can inform interpretation; IF/ICC protocol design belongs in its own guide.

Why is my staining missing, weak or wrong?
Situation	Likely cause	Next action
The positive tissue is blank, including ciliated bronchial cells reported as high (HPA tissue IHC).	Section, retrieval, primary antibody or detection failure is possible (general IHC practice).	Verify section integrity and reagent activity with controls, then optimize retrieval and antibody conditions one variable at a time (general IHC practice). No ABCG1-specific retrieval setting is supplied.
The whole section is brown and cell boundaries are hard to score (general IHC practice).	Excess detection signal, inadequate washing or endogenous activity may contribute (general IHC practice).	Review primary-omission and detection controls; adjust dilution, washing or chemistry-specific blocking as indicated by those controls (general IHC practice). Score only a resolved cellular pattern.
Staining is predominantly nuclear, away from the reported cytoplasmic pattern (HPA tissue IHC).	A detection artifact or nonspecific antibody signal is possible (general IHC practice).	Compare the nuclear counterstain and control sections, then reassess antibody conditions (general IHC practice). Predominant ER and Golgi localization does not support a nuclear call (UniProt P45844 subcellular location).
Adipocytes stain strongly despite an HPA not detected result (HPA tissue IHC).	Cross-reactivity or endogenous detection activity is possible (general IHC practice).	Check primary-omission and detection controls, and compare a reported positive tissue in the same run (general IHC practice). Treat the HPA negative as a comparator, given its low consistency with RNA expression (HPA tissue IHC).
A few macrophage-like cells stain, but their identity is uncertain (HPA tissue IHC).	Cell identification from chromogen and morphology alone may be uncertain (general IHC practice).	Review morphology and the counterstain before assigning the signal to macrophages (general IHC practice). HPA describes cytoplasmic expression including macrophages but supplies no macrophage-specific intensity threshold (HPA tissue IHC).
A cell edge signal appears alongside intracellular staining (general IHC practice).	ABCG1 can localize to the cell membrane as well as predominantly to ER and Golgi membranes (UniProt P45844 subcellular location).	Assess whether the edge signal is cell associated and reproducible in a control tissue (general IHC practice). Do not assign a specific membrane pool from chromogenic appearance alone.

Source: UniProt P45844 Human Protein Atlas tissue Human Protein Atlas subcellular

Experiment evidence

IHC & IF images showing ABCG1 staining

Formalin-fixed and paraffin-embedded human hepatocarcinoma reacted with ABCG1 Antibody (Center), which was peroxidase-conjugated to the secondary antibody, followed by DAB staining. This data demonstrates the use of this antibody for immunohistochemistry; clinical relevance has not been evaluated.

A01227-1 · IHCFormalin-fixed and paraffin-embedded human hepatocarcinoma reacted with ABCG1 Antibody (Center), which was peroxidase-conjugated to the seco

HPA · Cerebral cortexHuman Protein Atlas IHC, Cerebral cortex. Source: https://www.proteinatlas.org/ENSG00000160179-ABCG1/tissue/cerebral+cortex#imid_7883920

HPA · LungHuman Protein Atlas IHC, Lung. Source: https://www.proteinatlas.org/ENSG00000160179-ABCG1/tissue/lung#imid_7884223

HPA · ColonHuman Protein Atlas IHC, Colon. Source: https://www.proteinatlas.org/ENSG00000160179-ABCG1/tissue/colon#imid_7883838

HPA · LiverHuman Protein Atlas IHC, Liver. Source: https://www.proteinatlas.org/ENSG00000160179-ABCG1/tissue/liver#imid_7884263

HPA · ICC-IF HeLaHuman Protein Atlas immunofluorescence, HeLa, antibody HPA031470; green = ABCG1, blue = nucleus, red = microtubules.

← swipe / scroll for more images →

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

Sample controls for ABCG1 IHC & IF

🧪Run bronchus first and assess staining in ciliated cells, specifically the cilia axoneme, where HPA reports High ABCG1 staining (HPA: bronchus). Use adipose tissue as the negative tissue and assess its adipocytes, which HPA lists as Not detected; on the bronchus slide, nonciliated cells should serve only as a relative internal comparison because their negative status is not established by the supplied rows (HPA: adipose tissue; HPA: bronchus).

Positive control tissue: Bronchus (Ciliated cells (cilia axoneme), HPA High)

Negative control tissue: Adipose tissue (HPA Not detected)

ICC-IF cell lines (HPA subcellular resource): HPA ICC-IF images show ABCG1 in HeLa, MCF-7, U2OS, hTERT-RPE1 (serum starved), with annotated localisation: Golgi apparatus (supported), Vesicles (uncertain) (HPA subcellular).

Technical controls: Include a no-primary, secondary-only control and a host-species- and clonality-matched isotype control; use ABCG1-knockout material or, if appropriate for the antibody, an immunizing-peptide block as a biological specificity control (standard IHC practice). For chromogenic bronchus sections, quench endogenous peroxidase and check inflammatory cells for residual background before scoring epithelial staining (standard IHC practice).

⚠️Feasibility: The selected antibody caption documents formalin-fixed, paraffin-embedded human hepatocarcinoma stained with peroxidase and DAB, but reports no target-specific fixation window or fixation effect (catalog antibody A01227-1 caption). Retrieval dependence is unreported, so optimize antigen retrieval empirically for paraffin sections (standard IHC practice). No supplied evidence establishes that frozen sections or IF are easier; if assessing IF, distinguish specific signal from tissue autofluorescence (standard IF practice).

HPA tissue IHC evidence for ABCG1

Comprehensive Human Protein Atlas IHC scoring per tissue (reliability: Approved — Low 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
Bronchus	Ciliated cells (cilia axoneme)	High	Protein (IHC)	HPA →
Fallopian tube	Ciliated cells (cilia axoneme)	High	Protein (IHC)	HPA →
Nasopharynx	Ciliated cells (cilia axoneme)	High	Protein (IHC)	HPA →
Testis	Elongated or late spermatids	High	Protein (IHC)	HPA →
Adrenal gland	Glandular cells	Medium	Protein (IHC)	HPA →

Undetected expression · recommended negative controls

Tissue	Cell type	Level	Evidence	Source
Adipose tissue	Adipocytes	Not detected	Protein (IHC)	HPA →
Ovary	Ovarian stroma cells	Not detected	Protein (IHC)	HPA →
Prostate	Glandular cells	Not detected	Protein (IHC)	HPA →
Salivary gland	Glandular cells	Not detected	Protein (IHC)	HPA →
Soft tissue	Chondrocytes	Not detected	Protein (IHC)	HPA →

Section 3

Advanced ABCG1 IHC Tips

Troubleshoot ABCG1 staining in paraffin sections by checking retrieval, compartmental pattern and cell identity before assigning biological meaning.

How should I retrieve ABCG1 in paraffin sections when staining is weak?

Use citrate pH 6.0 heat-induced retrieval at 95–98 °C for 20 min on paraffin sections (page retrieval rule: cytoplasmic / membrane antigen). Compare retrieved sections with a no-retrieval section and a no-primary control, keeping detection and development identical across slides (standard IHC practice). ABCG1 has 6 transmembrane segments and a large cytoplasmic region at residues 1–426, so the antibody epitope’s location matters when interpreting weak staining (UniProt P45844 topology). If staining remains weak, test a more alkaline retrieval buffer on matched sections as a fallback, then retain the condition that improves compartmental signal without raising background (standard IHC practice).

Can fixation explain inconsistent ABCG1 staining across paraffin blocks?

Target-specific sensitivity of ABCG1 staining to fixation time or fixative is unknown from the supplied evidence; do not infer it from tissue patterns or protein topology (supplied evidence scope). The selected SKU A01227-1 has a formalin-fixed, paraffin-embedded hepatocarcinoma IHC example, but that single example does not establish fixation tolerance (selected-SKU IHC caption). For discrepant blocks, compare fixation records and section age, then stain matched control sections in the same run using identical citrate pH 6.0 retrieval and detection (page retrieval rule; standard IHC practice). Record whether morphology, control staining and ABCG1 signal change together before attributing the difference to fixation (standard IHC practice).

Should ABCG1 appear at the cell surface or within the cytoplasm?

Assess ABCG1 chiefly as intracellular membranous or granular cytoplasmic staining in paraffin sections: UniProt places it predominantly at ER and Golgi membranes, with cell membrane also listed (UniProt P45844 subcellular). HPA reports general cytoplasmic tissue staining, including macrophages, and supported Golgi localization in its subcellular data (HPA tissue IHC; HPA subcellular). Compare signal with a no-primary control and examine whether it tracks intact cells rather than tissue edges or debris (standard IHC practice). A purely nuclear pattern warrants antibody and detection troubleshooting because the supplied localization evidence identifies membrane-associated compartments, not a nuclear location (UniProt P45844 subcellular; HPA subcellular).

How can epitope placement change interpretation of ABCG1 IHC?

ABCG1 has 8 listed isoforms, so determine which sequence the catalog antibody recognizes before interpreting loss of staining as loss of all ABCG1 forms (UniProt P45844 isoforms). The protein has a cytoplasmic ATP transporter domain at residues 77–317 and a transmembrane domain at 415–673; accessibility can differ with epitope position in paraffin sections (UniProt P45844 domains; standard IHC practice). Check the antibody’s stated immunogen against the relevant isoforms, and compare staining with an independently validated antibody if available (standard IHC practice). Report the antibody and epitope information alongside the retrieval condition; the supplied caption establishes IHC use for SKU A01227-1 but does not establish isoform coverage (selected-SKU IHC caption).

How should an ABCG1 IF result complement chromogenic IHC?

Use IF as a separate localization check: HPA reports supported Golgi localization and uncertain vesicle localization in cell imaging, while UniProt also lists ER and cell membrane (HPA subcellular; UniProt P45844 subcellular). For tissue multiplexing, pair ABCG1 with a validated macrophage marker when assessing macrophages, because macrophage expression is reported, and verify each channel’s specificity with single-stain controls (UniProt P45844 tissue specificity; standard IF practice). Choose fluorophores away from the tissue’s strongest autofluorescence and inspect an unstained section before interpreting puncta (standard IF practice). Match permeabilisation to the mapped epitope: cytoplasmic regions require intracellular access, whereas an extracellular epitope may be assessed without permeabilisation (UniProt P45844 topology; standard IF practice).

What should I check when ABCG1 DAB staining is diffuse?

First compare the stained section with no-primary and detection-only controls, and confirm that the peroxidase block was applied before DAB development (standard chromogenic IHC practice). Reduce antibody concentration through a controlled titration, strengthen the protein block if needed, and keep wash and development conditions identical across matched sections (standard IHC practice). Judge residual signal against the expected intracellular membranous pattern and the HPA report of general cytoplasmic staining, including macrophages (UniProt P45844 subcellular; HPA tissue IHC). The selected-SKU caption documents peroxidase-linked detection followed by DAB in a paraffin section, but does not establish that diffuse staining is ABCG1-specific (selected-SKU IHC caption).

How can I score ABCG1 IHC without conflating cell abundance and intensity? ⚠ ANSWER MARKED FOR VERIFICATION

Define the cell population and compartment before scoring, because HPA describes cytoplasmic expression that includes macrophages and UniProt emphasizes intracellular membranes (HPA tissue IHC; UniProt P45844 subcellular). For a defined population, report percent positive cells and an H-score from 0–300, using intensity categories 0–3 with the same thresholds across sections (standard IHC scoring practice). If the question concerns macrophage burden, count ABCG1-positive cells per mm² and normalize to tissue area or to the number of macrophages identified independently (standard IHC quantification practice). Exclude necrosis, folds and edges from the analysis area, and report control performance and the scoring rule with each comparison (standard IHC practice).

What distinguishes credible ABCG1 staining from an IHC artefact?

Favor staining in intact cells with an intracellular membranous or cytoplasmic pattern, especially when assessing macrophages; those features fit the supplied localization and tissue observations (UniProt P45844 subcellular and tissue specificity; HPA tissue IHC). Treat isolated nuclear staining, sharp edge-only signal, necrotic deposits and signal persisting in a no-primary control as reasons to investigate artefact (UniProt P45844 subcellular; standard IHC practice). Check endogenous peroxidase blocking and compare DAB development on matched controls before assigning positive cells (standard chromogenic IHC practice). HPA labels its tissue staining Approved but reports low consistency with RNA expression, so interpret a positive section alongside controls and cell identity rather than as standalone proof of expression (HPA tissue IHC).

Boster reagents

Best ABCG1 / ATP-binding cassette sub-family G member 1 IHC Antibodies

A01227-1 has a human IHC image; M01227 lists human and rat IHC and ICC/IF applications but supplies no IHC or IF figure (catalog: image captions, applications and reactivity).

Real IHC data Formalin-fixed and paraffin-embedded human hepatocarcinoma reacted with ABCG1 Antibody (Center), which was peroxidase-conjugated to the secondary antibody, followed by DAB staining. This data demonstrates the use of this antibody for immunohistochemistry; clinical relevance has not been evaluated.

Anti-ABCG1 Antibody (Center)

Cat # A01227-1

View product →

A01227-1 renders with an image of formalin-fixed, paraffin-embedded human hepatocarcinoma stained by peroxidase and DAB (A01227-1 IHC caption). M01227 lists human and rat IHC and ICC/IF applications, but has no figure-backed card (catalog: M01227 applications, reactivity and image alts).

Which to pick: For human tissue IHC-P, choose A01227-1: its own image documents formalin-fixed, paraffin-embedded tissue, and its listed dilution is 1:10–1:50 (A01227-1 IHC caption; catalog: A01227-1 IHC dilution). For IF/ICC or rat samples, M01227 is the listed rabbit monoclonal option with human and rat reactivity; it has no IHC or IF figure, and its tissue fixative is unreported (catalog: M01227 host, clone, applications, reactivity and image alts).

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

References

UniProt Consortium. UniProt entry P45844 (ABCG1_HUMAN, ATP-binding cassette sub-family G member 1).
Human Protein Atlas. ABCG1 tissue IHC expression (reliability: Approved).
Human Protein Atlas. ABCG1 subcellular location (ICC-IF): Mainly localized to the Golgi apparatus and vesicles..
Human Protein Atlas. ABCG1 antibody validation summary (2 antibodies).
Depletion of Lipid Efflux Pump ABCG1 Triggers the Intracellular Accumulation of Extracellular Vesicles and Reduces Aggregation and Tumorigenesis of Metastatic Cancer Cells. Frontiers in oncology 2018 — PMC6191470.
Long non‑coding RNA AL355711 promotes smooth muscle cell migration through the ABCG1/MMP3 pathway. International journal of molecular medicine 2021 — PMC8510679.
Inositol hexaphosphate sensitizes hepatocellular carcinoma to oxaliplatin relating inhibition of CCN2-LRP6-β-catenin-ABCG1 signaling pathway. Journal of Cancer 2021 — PMC8425206.
ATP-binding cassette transporters ABCA1, ABCA7, and ABCG1 in mouse spermatozoa. Biochemical and biophysical research communications 2008 — PMC2976870.
PubMed PMID:8659545 — UniProt-cited evidence.
PubMed PMID:10950923 — UniProt-cited evidence.
PubMed PMID:11279031 — UniProt-cited evidence.