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- Table of Contents
STAG1 / Cohesin subunit SA-1 · Western blot design guide
Design a Western Blot for STAG1
Source-linked STAG1 Western blot protocol options, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-STAG1 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Evidence assembled September 2026 · For research use; verify linked source records and product datasheet before use
STAG1 Western Blot Experimental Design Guide
Expected bands, source-linked protocol options, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~144.4 kDa | |
| Observed band | ~155 kDa | |
| Gel | 5–20% (catalog A06471-1) | |
| Positive control | Adrenal gland (IHC candidate; verify WB) +4 more | |
| Negative control | Suggested KO / knockdown lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | Phosphorylated + Ubl conjugation | |
| Caveat | Phosphorylation-state controls | |
| Gene-set association | MSigDB Hallmark membership | |
| Isoform | 2 isoform(s) |
Section 1
Source-Linked STAG1 Western Blot Protocol Options
The A06471-1 protocol combines labelled catalog values with standard starting conditions. Published comparisons retain their own sample, reagent and detection scope.
| Sample / lysate | human HEL, human Hela (catalog A06471-1) |
| Gel % | 5–20% (catalog A06471-1) |
| Load | 30 ug; reducing conditions (catalog A06471-1) |
| Transfer | a nitrocellulose membrane at 150 mA for 50-90 minutes (catalog A06471-1) |
| Membrane | nitrocellulose membrane (catalog A06471-1) |
| Blocking | 5% non-fat milk/TBS for 1.5 hour at RT (catalog A06471-1) |
| Primary antibody | A06471-1 · 0.5 μg/mL (catalog A06471-1) |
| Primary incubation | overnight at 4°C (catalog A06471-1) |
| Secondary antibody | goat anti-rabbit IgG-HRP, 1:5000 (catalog A06471-1) |
| Secondary incubation | 1.5 hour at RT (catalog A06471-1) |
| Wash | TBS-0.1%Tween 3 times with 5 minutes each (catalog A06471-1) |
| Detection | ECL (catalog A06471-1) |
Section 2
What Is the Expected STAG1 Western Blot Band Size?
STAG1 is predicted at 144.4 kDa and observed at ~155 kDa; the cause of the difference is not established.
| Band at ~155 kDa | Empirical STAG1 band in reducing whole-cell lysates; confirm identity with a specificity control. |
| Band near 144.4 kDa | Compatible with the UniProt predicted mass, but identity requires confirmation. |
| Multiple bands at different masses | Could include isoforms 1 and 2; distinct migration has not been established. |
| Weak or absent band in lysate | Chromatin-associated nuclear STAG1 may be poorly recovered during extraction. |
💡Expected STAG1 appearanceUniProt predicts 144.4 kDa, while antibody QC reports a ~155 kDa band in reducing whole-cell lysates; confirm band identity with a specificity control because the cause of the difference is unknown.
| UniProt predicted molecular weight | Places the theoretical protein mass at 144.4 kDa; the empirical band is ~155 kDa. |
| Alternative splicing | Produces isoforms 1 and 2, whose relative masses and migration are not supplied. |
| Isoform 1 | May differ in size from isoform 2; its individual mass is unknown. |
| Isoform 2 | May differ in size from isoform 1; its individual mass is unknown. |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | Chromatin-associated nuclear STAG1 may be poorly extracted. | Check nuclear or chromatin-enriched fractions and include an extraction control. |
| Band higher than expected | The reported ~155 kDa band exceeds the 144.4 kDa predicted mass for an undetermined reason. | Compare with the reported band and confirm identity by STAG1 depletion. |
| Band lower than expected | An alternative isoform or degradation could produce a lower band; neither is established here. | Test band identity by STAG1 depletion and check sample integrity. |
| Multiple bands | Isoforms 1 and 2 are documented, but their separation on a blot is unknown. | Check which bands respond to STAG1 depletion. |
| Weak or no signal | Recovery of chromatin-associated STAG1 may be low. | Verify extraction and transfer with suitable controls. |
| Broad smear instead of sharp band | No supplied feature establishes a smear for STAG1. | Check sample integrity and repeat with a clean lysate and specificity control. |
Experiment evidence
Western blot images showing STAG1 band
A06471-1 · STAG1
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for STAG1 Western blot
🧪HPA-IHC candidate guidance (verify in WB): For positive controls for STAG1 in Western blot, you can use adrenal gland tissue, which shows high HPA expression.
Positive control: Adrenal gland (IHC candidate; verify WB)
Negative control: Suggested KO / knockdown lysate
Loading controls: Run GAPDH, β-actin, and a total-protein stain alongside the samples.
⚠️Feasibility: No HPA tissue is listed as not detected, so use siRNA knockdown or a KO line as a negative control.
HPA tissue expression evidence for STAG1
Comprehensive Human Protein Atlas IHC scoring per tissue. Rows are taken directly from the HPA tissue chart — click any row's HPA link to view the source.
Higher expression tissues · candidate positive controls from IHC
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Adrenal gland | glandular cells | High | Protein (IHC) | HPA → |
| Breast | adipocytes | High | Protein (IHC) | HPA → |
| Bronchus | respiratory epithelial cells | High | Protein (IHC) | HPA → |
| Caudate | glial cells | High | Protein (IHC) | HPA → |
| Cerebellum | cells in molecular layer | High | Protein (IHC) | HPA → |
Lower expression tissues · IHC evidence, not confirmed WB-negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|---|---|---|---|
| Lymph node | germinal center cells | Low | Protein (IHC) | HPA → |
| Adipose tissue | adipocytes | Medium | Protein (IHC) | HPA → |
| Appendix | glandular cells | Medium | Protein (IHC) | HPA → |
| Bone marrow | hematopoietic cells | Medium | Protein (IHC) | HPA → |
| Duodenum | glandular cells | Medium | Protein (IHC) | HPA → |
Section 3
Advanced STAG1 Western Blot Tips
Deeper troubleshooting and optimisation questions for STAG1, answered from its protein features.
How should STAG1 band migration be interpreted?
Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.
Could STAG1 isoforms produce different bands?
Isoforms · UniProt lists isoforms 1 and 2. Isoform 2 lacks residues 1150–1186 of the canonical sequence, so it may migrate differently. Confirm which isoform the antibody recognizes before assigning a second band.
Which STAG1 phosphorylation sites matter when interpreting bands?
PTM · UniProt lists phosphoserines at canonical positions 24, 756, 1062, 1065 and 1093. Check whether the antibody targets a region containing one of these sites. These annotations alone do not predict a visible band shift; antibody or paper numbering may differ from UniProt numbering.
Does this guide establish induction of STAG1?
Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.
What transfer method to use for STAG1 Western blot?
Transfer · STAG1 has a predicted mass of 144.4 kDa. Use transfer conditions suited to a protein of this size, such as a wet transfer, and check transfer efficiency near 150 kDa before interpreting a weak or missing signal.
How should blocking be optimized?
Blocking · Standard workflow guidance: follow the A06471-1 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.
How should STAG1 be quantified?
Quantitation · Standard workflow guidance: quantify only a validated target band within the linear exposure range. Use consistent sample preparation and loading, retain biological replicates, and avoid interpreting saturation or loading differences as regulation.
Why might STAG1 appear near 155 kDa instead of 144.4 kDa?
Interpretation · The supplied blot observation is approximately 155 kDa, while the predicted mass is 144.4 kDa. Use both as guides when identifying the band. The listed phosphorylation sites do not, by themselves, establish the cause of the difference.
STAG1 associates with chromatin. The supplied location note says most cohesin complexes leave chromosome arms during prophase, while centromeric complexes remain. When quantifying STAG1, compare samples with similar cell cycle composition and use the same extraction method, especially for chromatin fractions.
Compare them with the approximately 155 kDa observed band and the two annotated isoforms. Isoform 2 lacks canonical residues 1150–1186; phosphorylation is also annotated, but its presence alone does not establish a shifted band. Check antibody specificity before assigning any additional band to STAG1.
STAG1 is annotated in the nucleus and on chromosomes, with chromatin association that changes during prophase. Keep fractionation and extraction conditions consistent across samples, and interpret changes in a chromatin fraction alongside its corresponding total or soluble fraction when available.
STAG1 associates with chromatin. The supplied location note says most cohesin complexes leave chromosome arms during prophase, while centromeric complexes remain. When quantifying STAG1, compare samples with similar cell cycle composition and use the same extraction method, especially for chromatin fractions.
Compare them with the approximately 155 kDa observed band and the two annotated isoforms. Isoform 2 lacks canonical residues 1150–1186; phosphorylation is also annotated, but its presence alone does not establish a shifted band. Check antibody specificity before assigning any additional band to STAG1.
STAG1 is annotated in the nucleus and on chromosomes, with chromatin association that changes during prophase. Keep fractionation and extraction conditions consistent across samples, and interpret changes in a chromatin fraction alongside its corresponding total or soluble fraction when available.
Boster reagents
STAG1 Western Blot Antibodies
Catalog antibodies with Western blot application and product-specific WB images. Evaluate suitability with the reported sample, controls and experimental conditions.
Real WB data
Anti-SA1/STAG1 Antibody Picoband®
Cat # A06471-1
The catalog reports one anti-STAG1 Western blot antibody, A06471-1, with stated human reactivity. Its blot image uses human HEL and HeLa whole-cell lysates and shows a band near 155 kDa, versus an expected 144 kDa. Evidence is limited to this reported blot.
Which to pick: A06471-1 is the only listed option. Its reported Western blot uses human HEL and HeLa whole-cell lysates with the primary antibody at 0.5 μg/mL. Performance in other samples or species is not established by the supplied evidence.
Source: BosterBio STAG1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry Q8WVM7.
- Human Protein Atlas. STAG1 tissue expression.
- PMC12593008 — target-verified WB comparison
- PMC9616885 — target-verified WB comparison
- PMC5514935 — target-verified WB comparison