Recombinant Human FOXJ3 Protein: Handling & Usage Protocol

Recombinant Human FOXJ3 Protein is a forkhead box family transcription factor expressed as a recombinant human protein for use in biochemical and cell-biological research applications requiring defined, high-purity protein reagents.

Product Name

Recombinant Human FOXJ3 Protein

SKU

rp367806

Protein Family

Forkhead Box (FOX) Transcription Factor Family

Species Origin

Human (Homo sapiens)

Recommended Storage

-80°C for long-term storage; avoid repeated freeze-thaw cycles

Application

Biochemical assays, protein interaction studies, transcription factor research

Background: FOXJ3 and the Forkhead Transcription Factor Family

FOXJ3 (Forkhead Box J3) is a member of the evolutionarily conserved forkhead box (FOX) family of transcription factors, characterized by a highly conserved winged-helix DNA-binding domain known as the forkhead domain. FOX family proteins regulate a wide range of biological processes including cell cycle progression, differentiation, development, and metabolism. FOXJ3 has been implicated in the regulation of gene expression in various tissue contexts, and recombinant forms are used as defined tools for studying DNA-binding activity, protein–protein interactions, and downstream signaling pathways in vitro.

Recombinant Human FOXJ3 Protein (rp367806) produced by Aladdin Scientific enables researchers to conduct controlled biochemical experiments without reliance on cell lysates, providing reproducible results in transcription factor research.

Reconstitution Protocol

Follow these steps to reconstitute Recombinant Human FOXJ3 Protein prior to use:

1. Equilibrate to room temperature: Allow the vial to equilibrate at room temperature for approximately 10–15 minutes before opening to minimize condensation-related contamination.
2. Centrifuge the vial: Briefly centrifuge (e.g., 1,000 × g for 30 seconds) to pellet any protein that may have adhered to the lid or sides of the vial during shipping.
3. Add reconstitution buffer: Reconstitute the lyophilized protein in sterile, ultrapure water or the supplier-recommended buffer (typically PBS, pH 7.4, with a carrier protein such as 0.1% BSA if required). Add the buffer gently along the wall of the vial.
4. Mix gently: Do not vortex. Gently pipette or swirl to dissolve the protein completely. Allow 5–10 minutes for full dissolution if necessary.
5. Prepare aliquots: Divide the reconstituted protein into single-use aliquots to avoid repeated freeze-thaw cycles, which can degrade protein activity.

Note: Specific reconstitution volume and buffer conditions should be confirmed against the product-specific Certificate of Analysis (CoA) provided with the lot.

Storage, Stability, and Handling Recommendations

Long-term storage: Store lyophilized protein at -20°C or -80°C in a frost-free freezer. Lyophilized protein is generally stable for 12 months from date of receipt when stored properly.

Reconstituted protein: Once reconstituted, aliquot and store at -80°C. Reconstituted protein is typically stable for up to 3 months at -80°C. Avoid repeated freeze-thaw cycles; each cycle may reduce activity.

Working stocks: For short-term use (up to 1 week), reconstituted protein may be stored at 4°C. Add a carrier protein such as 0.1% BSA to stabilize the protein during refrigerated storage if recommended by the CoA.

Handling precautions: Always work on ice when handling reconstituted protein. Use low-binding microcentrifuge tubes to minimize adsorption losses. Wear appropriate personal protective equipment (PPE) in accordance with your institution's biosafety guidelines.

Experimental Applications

Recombinant Human FOXJ3 Protein is suitable for a range of in vitro research applications, including but not limited to:

• Electrophoretic Mobility Shift Assays (EMSA): To study DNA-binding activity of FOXJ3 with target forkhead response elements (FHREs).
• Protein–Protein Interaction Studies: Co-immunoprecipitation (Co-IP) or pull-down assays to identify interacting partners of FOXJ3.
• Enzyme-Linked Immunosorbent Assay (ELISA) Standard: As a positive control or calibration standard in FOXJ3-specific immunoassays.
• Antibody Validation: As an antigen to validate anti-FOXJ3 antibody specificity by Western blot or dot blot.
• Functional Biochemical Assays: In vitro transcription assays or reporter assays utilizing recombinant protein as an activating or repressing factor.

Optimize protein concentrations empirically for each application. Refer to current literature for guidance on expected activity ranges for FOXJ3 in specific assay formats.

Quality Control and Regulatory Considerations

Purity and identity: Each lot of Recombinant Human FOXJ3 Protein is subject to quality control testing. Verify purity by SDS-PAGE and identity by Western blot prior to use. A Certificate of Analysis (CoA) is available for each lot and should be reviewed before experimental use.

Endotoxin testing: For cell-based assays, ensure the endotoxin level is within acceptable limits (typically <1.0 EU/μg) as specified on the CoA, since endotoxin contamination can confound biological results.

Research use only (RUO): Recombinant Human FOXJ3 Protein (rp367806) is intended for research use only and is not approved for diagnostic or therapeutic applications in humans or animals.

Biosafety classification: Handle according to institutional biosafety guidelines. This recombinant protein is not classified as a select agent; however, standard laboratory safety precautions apply.

Frequently asked questions

How should I reconstitute Recombinant Human FOXJ3 Protein (rp367806)?

Allow the vial to reach room temperature, briefly centrifuge to pellet any dried protein, then add sterile ultrapure water or the recommended buffer (e.g., PBS pH 7.4 ± 0.1% BSA) gently along the vial wall. Mix by gentle pipetting — do not vortex — and aliquot immediately for storage at -80°C. Always confirm specific volume and buffer requirements on the product CoA.

How many freeze-thaw cycles can Recombinant Human FOXJ3 Protein tolerate?

Repeated freeze-thaw cycles are known to degrade recombinant protein activity and should be minimized. It is best practice to prepare single-use aliquots upon reconstitution and store them at -80°C, thereby limiting each aliquot to a single thaw. The exact tolerance for freeze-thaw cycles is product-lot-specific and should be verified with the CoA or by contacting Aladdin Scientific technical support.

Is Recombinant Human FOXJ3 Protein (rp367806) suitable for use as a Western blot positive control?

Yes, recombinant proteins are widely used as positive controls in Western blot experiments to confirm antibody specificity and assay performance. When using rp367806 as a Western blot standard, load an appropriate quantity alongside experimental samples and ensure the expected molecular weight band is consistent with the recombinant construct size as stated on the CoA. Consult the CoA for molecular weight and tag information before use.

What is the biological function of FOXJ3?

FOXJ3 is a member of the forkhead box (FOX) transcription factor family, which regulates gene expression through binding to forkhead response elements (FHREs) in target gene promoters. FOX family members are involved in diverse processes including development, differentiation, and metabolic regulation. The specific biological roles of FOXJ3 in human physiology are an active area of research; consult current peer-reviewed literature for the most up-to-date functional data.

Can rp367806 be used in cell-based functional assays?

Recombinant Human FOXJ3 Protein may be used in cell-free in vitro transcription or reporter assays. For intracellular applications requiring delivery of recombinant protein into live cells, a suitable protein transduction strategy (e.g., fusion to a cell-penetrating peptide or electroporation) would be required. Endotoxin levels should be confirmed to be within acceptable limits before use in any cell-based system. Always verify suitability for the specific assay format by consulting current literature and the product CoA.

References

1. Kaestner KH, Knochel W, Martinez DE. Unified nomenclature for the winged helix/forkhead transcription factors. Genes Dev. 2000;14(2):142-146. doi:10.1101/gad.14.2.142
2. Hannenhalli S, Kaestner KH. The evolution of Fox genes and their role in development and disease. Nat Rev Genet. 2009;10(4):233-240. doi:10.1038/nrg2523
3. Aladdin Scientific. Recombinant Human FOXJ3 Protein, SKU rp367806. Product datasheet. Aladdin Scientific.

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