RSPO1 Mouse mAb: Usage Guidelines & Technical Overview

RSPO1 Mouse mAb is a monoclonal antibody raised in mouse and directed against human RSPO1 (R-spondin 1), a secreted activator of the WNT/β-catenin signaling pathway, supplied in PBS buffer and suitable for a range of standard immunoassay applications.

Catalog SKU

Ab350698

Clone Type

Mouse Monoclonal Antibody (mAb)

Formulation

PBS only (no carrier protein or preservative indicated)

Target Protein

RSPO1 (R-spondin 1), a WNT/β-catenin signaling potentiator

Host Species

Mouse

Recommended Storage

−20 °C for long-term; 4 °C for short-term use (≤1 month); avoid repeated freeze-thaw cycles

Background: RSPO1 and Its Role in WNT Signaling

R-spondin 1 (RSPO1) is a member of the R-spondin family of secreted proteins (RSPO1–RSPO4) that function as potent activators of the canonical WNT/β-catenin signaling pathway. RSPO1 acts by binding to LGR4/5/6 receptors and neutralizing the RNF43/ZNRF3 E3 ubiquitin ligases that would otherwise target Frizzled receptors for degradation, thereby amplifying downstream WNT signals.

RSPO1 plays critical roles in stem cell maintenance, intestinal epithelial renewal, sex determination, and tissue homeostasis. Its overexpression has been linked to several cancers, making it a target of ongoing therapeutic and biomarker research. An antibody with high specificity for RSPO1 is therefore essential for researchers investigating WNT pathway dysregulation, organoid biology, and oncology.

Reagent Specifications and Storage Guidelines

Product: RSPO1 Mouse mAb (SKU: Ab350698, referenced as absea#KC-1817).
Format: Purified mouse monoclonal antibody supplied in PBS (phosphate-buffered saline) without additional stabilizers, carrier proteins, or sodium azide unless otherwise stated on the product datasheet.

Storage recommendations:

• Store at −20 °C for long-term preservation (up to 12 months from date of receipt).
• For working stocks used within one month, aliquots may be kept at 4 °C.
• Prepare single-use aliquots upon first thaw to avoid repeated freeze-thaw cycles, which can denature the antibody and reduce specific activity.
• Do not store in frost-free freezers that undergo automatic defrost cycles.

Note: Because the formulation is PBS only, consider adding a carrier protein (e.g., 0.1% BSA) if further dilution or long-term storage at 4 °C is required, to prevent adsorptive losses at low antibody concentrations.

Recommended Application Protocols

RSPO1 Mouse mAb is suitable for standard immunoassay applications. The following general protocols are provided as starting points; optimization may be required depending on sample type and instrument setup.

Western Blot (WB)

1. Separate 20–40 µg of total protein per lane by SDS-PAGE under reducing conditions.
2. Transfer to PVDF or nitrocellulose membrane.
3. Block with 5% non-fat milk or 5% BSA in TBST for 1 hour at room temperature.
4. Incubate with RSPO1 Mouse mAb at a recommended starting dilution of 1:500–1:2000 in blocking buffer, overnight at 4 °C.
5. Wash 3 × 10 min with TBST.
6. Incubate with HRP-conjugated anti-mouse secondary antibody (1:5000–1:10000) for 1 hour at RT.
7. Detect by ECL. Expected band: ~27–35 kDa (mature secreted form; may vary with glycosylation).

Immunohistochemistry (IHC)

1. Deparaffinize and rehydrate FFPE sections.
2. Perform antigen retrieval (citrate buffer pH 6.0, 95 °C, 20 min recommended as starting condition).
3. Block endogenous peroxidase and non-specific binding.
4. Incubate with primary antibody at 1:100–1:400 overnight at 4 °C.
5. Apply polymer-HRP anti-mouse secondary system and develop with DAB.
6. Counterstain with hematoxylin.

Immunofluorescence (IF)

1. Fix cells with 4% paraformaldehyde (10 min, RT); permeabilize with 0.1% Triton X-100 if intracellular staining is required.
2. Block with 5% normal goat serum in PBS for 30 min.
3. Incubate with RSPO1 Mouse mAb at 1:50–1:200 for 1 hour at RT or overnight at 4 °C.
4. Wash and apply fluorophore-conjugated anti-mouse secondary antibody.
5. Mount with DAPI-containing mounting medium.

All dilutions are starting recommendations. Titration experiments are strongly encouraged for each new lot and sample matrix.

Troubleshooting Common Issues

The table below summarizes frequent issues encountered with mouse monoclonal antibodies in immunoassays and recommended corrective actions applicable to RSPO1 Mouse mAb.

Problem	Likely Cause	Recommended Action
No signal (WB)	Antibody concentration too low; protein degradation; transfer failure	Increase antibody concentration; verify protein integrity by Coomassie stain; check transfer efficiency with Ponceau S
High background	Insufficient blocking; secondary antibody cross-reactivity; antibody concentration too high	Extend blocking time; titrate primary antibody down; use species-matched isotype control
Multiple non-specific bands	Non-reducing conditions; proteolytic degradation of sample	Confirm reducing SDS-PAGE; add protease inhibitors to lysis buffer
Weak IHC signal	Inadequate antigen retrieval; over-fixation of tissue	Optimize retrieval buffer (try EDTA pH 9.0 as alternative); reduce fixation time
Loss of antibody activity after freeze-thaw	PBS-only formulation sensitive to repeated cycling	Aliquot upon first thaw; add 0.1% BSA as stabilizer if further dilution is needed

Frequently asked questions

What is the recommended dilution range for RSPO1 Mouse mAb in Western blot?

A starting dilution of 1:500 to 1:2000 is recommended for Western blot. Because optimal dilution depends on sample type, protein abundance, and detection system, titration experiments should be performed for each new application and lot.

Why is the formulation PBS only, and does this affect storage stability?

A PBS-only formulation avoids azide or carrier protein that could interfere with certain assays; however, it also means the antibody is more susceptible to adsorptive loss and denaturation when stored at dilute concentrations or at 4 °C for extended periods. To maintain stability, aliquot the antibody upon first thaw and store at −20 °C. For working dilutions stored at 4 °C, adding 0.1% BSA as a carrier is advisable.

Which tissues or cell lines are suitable positive controls for RSPO1 detection?

RSPO1 is predominantly expressed in intestinal epithelium, ovary, and liver tissues, making these suitable positive control sources. Cell lines reported to endogenously express RSPO1 include certain colorectal cancer lines; however, researchers should verify expression in their specific model system, as expression levels vary by cell line and passage.

Is RSPO1 Mouse mAb suitable for immunoprecipitation (IP)?

The product description does not specify validated applications beyond standard immunoassays. Whether this antibody is suitable for IP should be confirmed by the user through pilot experiments. Monoclonal antibodies with epitopes that remain accessible under native conditions are generally compatible with IP, but this must be empirically validated.

How should I confirm antibody specificity using a negative control?

Use an isotype-matched mouse IgG control at the same concentration as the primary antibody in parallel experiments. Additionally, RSPO1-knockout or RSPO1-knockdown cell lysates or tissues, where available, provide the most rigorous negative controls. Omitting the primary antibody while retaining the secondary antibody is the minimum recommended control.

References

1. Aladdin Scientific product datasheet: RSPO1 Mouse mAb, SKU Ab350698 (absea#KC-1817), PBS formulation.
2. de Lau W, et al. Lgr5 homologues associate with Wnt receptors and mediate R-spondin signalling. Nature. 2011;476(7360):293–297. doi:10.1038/nature10337
3. Hao HX, et al. ZNRF3 promotes Wnt receptor turnover in an R-spondin-sensitive manner. Nature. 2012;485(7397):195–200. doi:10.1038/nature11019
4. Kazanskaya O, et al. R-Spondin2 is a secreted activator of Wnt/beta-catenin signaling and is required for Xenopus myogenesis. Dev Cell. 2004;7(4):525–534. doi:10.1016/j.devcel.2004.07.019

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.