What Is HOXD4? Gene, Protein, and Biological Context

HOXD4 (Homeobox D4) is a member of the HOX gene family, a highly conserved group of transcription factors that govern body plan specification along the anterior-posterior axis during embryonic development. The HOX genes are organized into four genomic clusters (HOXA, HOXB, HOXC, and HOXD) in mammals, and their expression is spatially and temporally regulated in a manner that directly corresponds to their chromosomal position — a phenomenon known as colinearity.

The HOXD4 gene is located within the HOXD cluster on human chromosome 2q31. The HOXD4 protein contains a characteristic 60-amino-acid homeodomain, a helix-turn-helix DNA-binding motif that enables sequence-specific recognition of target gene promoters and enhancers. Through this mechanism, HOXD4 acts as a master regulator of downstream gene networks controlling cell fate, tissue identity, and organogenesis.

In vertebrates, HOXD4 is particularly important for specifying the identity of cervical vertebrae and posterior hindbrain segmentation. Dysregulation of HOXD4 expression has been reported in several cancers, making it a subject of interest in oncology research in addition to developmental biology.

Recombinant Human HOXD4 Protein: Specification and Quality Attributes

Aladdin Scientific's Recombinant Human HOXD4 Protein (SKU: rp365857) is produced using recombinant expression technology to deliver a high-quality, research-grade protein suitable for a wide range of in vitro applications. Recombinant production ensures batch-to-batch consistency and the absence of native-source contaminants that may otherwise confound experimental results.

Key quality considerations for recombinant HOX-family proteins include:

• Purity: Recombinant proteins intended for biochemical assays are typically verified by SDS-PAGE and/or HPLC to confirm purity levels appropriate for research use. Researchers should consult the Certificate of Analysis (CoA) supplied with each lot for confirmed purity data.
• Biological Activity: Functional verification may include DNA-binding assays or transcriptional reporter assays to confirm the homeodomain retains its native fold and sequence-specific binding capacity.
• Formulation and Storage: Lyophilized or liquid formulations may be available; proper reconstitution and aliquoting are essential to maintain protein integrity. Storage at -80°C is generally recommended to prevent freeze-thaw-related degradation.
• Tag Configuration: Recombinant HOXD4 may be expressed with an affinity tag (e.g., His-tag or GST-tag) to facilitate purification and downstream pull-down experiments.

Researchers are advised to review the product datasheet for confirmed specification details, including molecular weight, host expression system, and recommended storage conditions specific to this lot.

Research Applications of Recombinant Human HOXD4 Protein

Recombinant Human HOXD4 Protein is a versatile reagent supporting multiple research disciplines. Primary application areas include:

Developmental Biology and Axial Patterning

HOXD4 is a key regulator of vertebrate anterior-posterior axis specification. Recombinant protein is used in cell-free transcription assays, microinjection experiments, and in vitro reconstitution studies to probe how HOXD4 coordinates with cofactors such as TALE-class proteins (PBX and MEIS family members) to modulate target gene expression.

Protein-DNA Interaction Studies

The homeodomain of HOXD4 confers sequence-specific DNA binding. Recombinant HOXD4 is suitable for electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP) input controls, fluorescence polarization binding assays, and surface plasmon resonance (SPR) experiments to characterize its interaction with cognate DNA sequences.

Cancer Biology Research

Altered HOX gene expression, including HOXD4, has been observed in hematological malignancies and solid tumors. Recombinant HOXD4 protein enables in vitro studies investigating its role in oncogenic transcriptional programs, providing a tool for drug screening assays targeting HOX-DNA or HOX-cofactor interactions.

Antibody and Assay Development

High-purity recombinant HOXD4 serves as a reliable antigen for antibody production, ELISA standard curve construction, and Western blot positive controls, ensuring experimental reproducibility across laboratories.

Handling, Reconstitution, and Storage Recommendations

Proper handling of Recombinant Human HOXD4 Protein is essential to preserve its structural integrity and biological activity. The following general guidelines apply; always refer to the product-specific datasheet for authoritative instructions.

• Reconstitution: If supplied in lyophilized form, reconstitute in the recommended buffer (typically sterile PBS or Tris-based buffer with a carrier protein such as 0.1% BSA) at the volume specified in the datasheet to achieve the target concentration. Allow the vial to equilibrate to room temperature before opening to prevent condensation.
• Aliquoting: Prepare single-use aliquots immediately after reconstitution to minimize repeated freeze-thaw cycles, which can lead to protein aggregation and loss of activity.
• Storage Temperature: Store lyophilized protein at -20°C or -80°C as directed. Reconstituted protein should be stored at -80°C and used within the timeframe specified by the manufacturer.
• Avoid Repeated Freeze-Thaw: Each freeze-thaw cycle risks denaturation of the homeodomain and reduction in DNA-binding activity. Use freshly thawed aliquots for each experiment.
• Working Concentration: Optimize protein concentration empirically for each assay type. Typical EMSA experiments use nanomolar to low micromolar concentrations of recombinant transcription factors.

If any unusual turbidity, precipitation, or color change is observed upon reconstitution, contact Aladdin Scientific technical support before use.