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SOX1 · Western blot design guide
Design a Western Blot for SOX1
Real validated SOX1 Western blot protocols, expected-band and isoform facts, troubleshooting for weak or shifted signal, and recommended anti-SOX1 WB antibodies. Everything you need to plan the experiment before you commit precious samples.
Last reviewed: May 2026 · Scientific review: Boster Bio technical team
SOX1 Western Blot Experimental Design Guide
Expected bands, validated protocols, controls and antibodies — the at-a-glance facts below, then the full design guide.
Must know before running
| Expected band | ~39 kDa | |
| Observed band | 39 kDa | |
| Gel | 10–12% | |
| Negative control | siRNA / KO lysate |
Important caveats
Reasons your observed band may differ from the expected size.
| PTM | — | |
| Caveat | — | |
| Regulation | LPS-induced | |
| Isoform | 1 isoform(s) |
Section 1
Real Curated SOX1 Western Blot Protocols
Literature-validated Western blot parameters for SOX1 — gel percentage, transfer, blocking, antibody incubation and detection, extracted from published methods.
| Sample / lysate | T-ALL cell lines (Jurkat, CCRF-CEM, T-ALL-104), H9, HEK-293T cells; xenograft mouse tumor tissues |
| Gel % | 10–12% |
| Membrane | PVDF membranes (Thermo Fisher Scientific) |
| Blocking | 5% skimmed milk for 1 h |
| Primary antibody | 1:1000 |
| Primary incubation | 4°C overnight |
| Secondary antibody | 1:5000 |
| Secondary incubation | 1 h at room temperature |
| Detection | enhanced chemiluminescent (ECL) kit |
Section 2
What Is the Expected SOX1 Western Blot Band Size?
SOX1 has a 39 kDa predicted mass and runs true to size at an observed 39 kDa band, since it lacks glycosylation, disulfide bonds, cleavage sites, or splice isoforms.
| single sharp band at ~39 kDa | predicted mass has no glycosylation, disulfide, or cleavage modifiers, so SOX1 runs true to its calculated size |
| no additional bands or doublets | only one annotated isoform exists, so no alternative-splicing bands are expected |
| band position unchanged with or without reducing agent | no disulfide bonds or oligomerization are annotated, so there is no dimer band to collapse upon reduction |
| band size unchanged after glycosidase treatment | no glycosylation sites are annotated, so deglycosylation has no effect on migration |
| signal weak or absent unless nuclear lysis is thorough | SOX1 is a nuclear protein, so incomplete nuclear extraction can undercapture it in whole-cell lysate |
💡Expected SOX1 appearanceExpect a single sharp band at 39 kDa in nuclear-inclusive lysates, matching both the predicted mass and the empirically observed 39 kDa band, since SOX1 has no glycosylation, disulfide bonds, cleavage, or splice isoforms to shift its size.
| predicted molecular weight (39 kDa, 391 aa) | sets the baseline band position, and the empirically observed 39 kDa band matches this closely |
| absence of glycosylation sites | prevents any upward smear or shift above the calculated mass |
| absence of disulfide bonds / no oligomerization | keeps the band as a stable monomer with no ~78 kDa dimer band under non-reducing conditions |
| single annotated isoform | limits the blot to one expected band rather than multiple isoform-driven bands |
| nuclear subcellular localization | requires efficient nuclear lysis to release full signal; weak nuclear extraction lowers apparent band intensity |
| Situation | Likely cause | Next action |
|---|---|---|
| No band in lysate | nuclear membrane not adequately disrupted, leaving SOX1 in an insoluble nuclear pellet | use a nuclear extraction or RIPA buffer with sonication and confirm nuclear fraction is loaded |
| Weak or no signal | SOX1 expression is tissue-restricted (neural progenitor and lens tissue), so unrelated cell lines show little endogenous protein | load a known-positive tissue such as fetal brain lysate and increase total protein loaded |
| Multiple bands | antibody cross-reactivity with other SOXB1-family members sharing a similar HMG DNA-binding domain | confirm specificity with a SOX1 knockdown or knockout lysate control |
| Band higher than expected | residual chromatin or DNA bound to the nuclear protein was not fully sheared before loading | treat lysate with benzonase or sonicate thoroughly before boiling in sample buffer |
| Band lower than expected | proteolytic degradation of the protein during nuclear lysate preparation | include protease inhibitors and keep samples cold throughout extraction |
Experiment evidence
Western blot images showing SOX1 band
PB9403 · SOX1
← swipe / scroll for more images →
Real WB data behind the band-size expectations in this section.
Sample controls for SOX1 Western blot
🧪For positive controls for SOX1 in Western blot, you can use lysate from cells transiently transfected to overexpress SOX1, since no HPA tissue or cell-line expression data is available for this transcription factor.
Positive control: SOX1-overexpression lysate
Negative control: no HPA expression data available; use siRNA knockdown or KO line
Loading controls: Run GAPDH and β-actin alongside a total-protein stain (e.g., stain-free gel, Ponceau S, or REVERT) as loading controls.
⚠️Feasibility: As a nuclear transcription factor lacking HPA expression data, no validated positive tissue exists, so antibody specificity should be confirmed with an overexpression system paired with siRNA knockdown or a KO line.
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.
Positive expression · recommended positive controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Undetected expression · recommended negative controls
| Tissue | Cell type | Level | Evidence | Source |
|---|
Section 3
Advanced SOX1 Western Blot Tips
Deeper troubleshooting and optimisation questions for SOX1, answered from its protein features.
Why does SOX1 migrate close to its predicted 39 kDa mass?
SOX1 has no annotated glycosylation, disulfide bonds, or other modifications, so its apparent mass matches the calculated 39 kDa. Empirical blots consistently report the band at 39 kDa, confirming minimal post-translational mass addition. Treat small deviations (1-3 kDa) as normal gel migration variation, not evidence of a processed or modified form.
Could SOX1 isoforms produce multiple bands?
UniProt annotates only a single SOX1 isoform, so a clean single band near 39 kDa is expected. Extra bands are not isoform variants; they more likely reflect antibody cross-reactivity with other SOXB1 family members (SOX2, SOX3), which share a highly conserved HMG-box domain, or nonspecific binding and degradation.
Is SOX1 expression induced during neural differentiation?
SOX1 has no annotated PTMs, so induction is transcriptional rather than a modification-driven mass shift. As a neuroectodermal transcription factor, SOX1 protein levels rise sharply during neural induction protocols (e.g., dual SMAD inhibition, retinoic acid treatment), so expect low or absent signal in undifferentiated cells and a strong 39 kDa band after differentiation.
How should blocking be optimized for SOX1 detection?
Because SOX1 is a low-abundance, chromatin-bound nuclear transcription factor, use 5% non-fat milk or BSA blocking and extend primary antibody incubation overnight at 4C to maximize sensitivity. Ensure nuclear lysates are fully solubilized (sonication or benzonase treatment) before blocking, since incomplete chromatin release under-represents true SOX1 levels on the blot.
What transfer method to use for SOX1 Western blot?
Standard wet or semi-dry transfer onto PVDF membrane works well for the 39 kDa SOX1 protein; no extended transfer time is needed as for larger proteins. Since SOX1 is nuclear and DNA-binding, ensure lysates are fully denatured and chromatin-released before loading so transfer efficiency reflects true protein levels rather than incomplete extraction.
How should SOX1 band intensity be quantified?
Quantify the single ~39 kDa band by densitometry, normalizing to a nuclear-specific loading control such as Histone H3 or Lamin B1 rather than cytoplasmic controls like GAPDH or actin, since SOX1 is restricted to the nucleus. This avoids compartment mismatch that can distort relative expression comparisons across differentiation time points.
What explains unexpected bands on a SOX1 blot?
Bands near 34-37 kDa likely reflect antibody cross-reactivity with the closely related SOXB1 proteins SOX2 or SOX3, which share a conserved HMG-box. Bands below 39 kDa may indicate degradation from incomplete nuclear lysis handling. Confirm specificity with a SOX1 knockdown or knockout control lysate alongside positive neural progenitor samples.
Boster reagents
Best SOX1 Western Blot Antibodies
BosterBio's SOX1 antibodies are among the best-performing WB antibodies on the market — well cited, thoroughly validated, and orthogonally cross-validated against negative tissues and complementary methods.
Real WB data
Anti-SOX1 Antibody Picoband®
Cat # PB9403
Our recommended anti-SOX1 Western blot antibody is best-performing, extensively cited, and thoroughly validated, with cross-validation across multiple tissue and cell lysates confirming specific, reproducible detection of the ~39 kDa SOX1 band.
Which to pick: Only one anti-SOX1 antibody, PB9403, is currently listed; it includes an actual WB validation image detecting SOX1 at the predicted ~39 kDa size in rat brain tissue and NIH3T3 cell lysates, making it the clear default choice.
Source: BosterBio SOX1 gene-info card — filtered to Western-blot-capable antibodies; each card shows that product's actual WB validation figure.
References
- UniProt Consortium. UniProt entry O00570.
- Human Protein Atlas. SOX1 tissue expression.