PRRX1 Antibody

What is PRRX1 and what functions make it important in research applications?

PRRX1 is a transcription factor belonging to the paired homeobox family that contains both a homeobox DNA-binding domain and an OAR domain. It functions as a transcriptional co-activator that enhances the DNA-binding activity of serum response factor (SRF), thereby mediating the induction of SRF-dependent gene expression by growth and differentiation factors . PRRX1 exists in two alternatively spliced isoforms, designated Prrx1a (PMX-1a) and Prrx1b (PMX-1b), which differ in their C-terminal regions . The full-length protein is approximately 245 amino acids with a molecular weight of around 27 kDa .

PRRX1 has been implicated in diverse biological processes including:

• Regulation of mesenchymal cell fate determination

• Influencing adipogenesis and fat cell development

• Mediating injury response and wound healing in dermal tissues

• Contributing to cancer progression, particularly in promoting chemoresistance in bladder cancer and colorectal cancer stemness

These varied functions make PRRX1 antibodies valuable tools for investigating development, tissue regeneration, and cancer biology.

What applications are PRRX1 antibodies validated for in laboratory research?

PRRX1 antibodies have been validated for multiple research applications across various experimental systems. Based on the available data, these antibodies can be utilized in:

• Western Blotting (WB): Most commercial PRRX1 antibodies are validated for western blot applications with recommended dilutions ranging from 1:2000 to 1:10,000 . For example, Thermo Fisher's OTI1E10 antibody effectively detects PRRX1 in cell lysates at a recommended dilution of 1:2000 .

• Immunohistochemistry (IHC): PRRX1 antibodies work in both paraffin-embedded (IHC-p) and frozen tissue sections (IHC-f). Typical working dilutions range from 1:100 to 1:150 for monoclonal antibodies . The Affinity Biosciences PRRX1 antibody and multiple Thermo Fisher antibodies are validated for IHC applications .

• Immunocytochemistry/Immunofluorescence (ICC/IF): For cellular localization studies, antibodies like Thermo Fisher's OTI6A4 and OTI1E10 clones demonstrate specific nuclear staining of PRRX1 at approximately 1:100 dilution .

• ELISA: Several PRRX1 antibodies are validated for ELISA applications, particularly useful for quantitative analysis of PRRX1 in biological fluids or cell lysates .

The reactivity of commercially available PRRX1 antibodies typically includes human, mouse, and rat proteins, with some antibodies also predicted to work in other species such as pig, bovine, horse, rabbit, dog, and chicken .

How can researchers differentiate between PRRX1 isoforms in experimental systems?

PRRX1 exists in two main isoforms, which presents challenges for researchers needing to distinguish between their functions. Here's how to differentiate them:

• Isoform characteristics:

  • Prrx1a: The full-length isoform (245 amino acids), spanning -101 to +820 bp relative to the start codon

  • Prrx1b: A shorter isoform (approximately 217 amino acids) spanning -101 to +676 bp, lacking the C-terminal OAR domain

• Antibody-based differentiation approaches:

  • Isoform-specific antibodies: Select antibodies targeting unique regions in the C-terminus present only in Prrx1a but absent in Prrx1b

  • Epitope mapping: Review product information for epitope location - antibodies targeting shared N-terminal regions will detect both isoforms

  • Western blot analysis: The slight size difference (approximately 3-4 kDa) between isoforms may be resolved on high-percentage SDS-PAGE gels with extended running times

• RNA-based differentiation:

  • RT-PCR with isoform-specific primers: As described in search result , researchers can use primers that specifically amplify each isoform:

    • Prrx1a/Prrx1b sense: 5′-CCTCTTTCTTCCCCACTCG-3′

    • Prrx1a antisense: 5′-GGCGGATGAAGATATGACAGA-3′

    • Prrx1b antisense: 5′-ATGGCGCTTTTCAGTGTCTT-3′

  • qRT-PCR: Design primers spanning the junction regions unique to each isoform for quantitative analysis

• Recombinant expression systems:

  • Express individual isoforms as positive controls using constructs like pMSCVneo-Prrx1a and pMSCVneo-Prrx1b

  • Tag isoforms differentially (e.g., Flag-Prrx1a, HA-Prrx1b) for separate detection and functional studies

Understanding which isoform is being detected is crucial as they may have distinct functions in different biological contexts.

What methodological approaches improve detection specificity when using PRRX1 antibodies?

Ensuring specific detection of PRRX1 requires rigorous methodological approaches to minimize artifacts and non-specific signals:

• Proper antibody validation:

  • Use multiple antibodies targeting different PRRX1 epitopes to confirm staining patterns

  • Include positive controls like C6 cells, which have been validated for PRRX1 expression

  • Incorporate PRRX1 knockdown or knockout samples as negative controls

  • Verify antibody specificity through peptide competition assays

• Optimization of sample preparation:

  • Fixation: Test multiple fixation methods (paraformaldehyde, methanol/acetone) and durations

  • Antigen retrieval: Compare heat-induced epitope retrieval methods using citrate (pH 6.0) or EDTA-based buffers (pH 9.0)

  • Permeabilization: Adjust detergent concentration (Triton X-100, Tween-20) to enhance nuclear epitope accessibility while maintaining tissue integrity

• Western blot refinements:

  • Molecular weight verification: PRRX1 should appear at approximately 27 kDa

  • Include positive control lysates from cells with known PRRX1 expression

  • Use gradient gels (4-20%) to better resolve potential isoforms

  • Optimize transfer conditions for efficient transfer of proteins in the 20-30 kDa range

• Immunohistochemistry/immunofluorescence enhancements:

  • Employ indirect detection systems with species-specific secondary antibodies

  • Include autofluorescence quenching steps when performing IF on tissues

  • Use nuclear counterstains (DAPI, Hoechst) to verify nuclear localization

  • Consider tyramide signal amplification for low-abundance detection

• Controls for cross-reactivity:

  • Test antibodies on tissues from PRRX1 knockout models when available

  • Include isotype control antibodies at matching concentrations

  • Verify specificity in tissues with known differential expression patterns

These methodological refinements will significantly improve the reliability and specificity of PRRX1 detection across experimental platforms.

Which tissues and cell types express PRRX1 at levels suitable for antibody-based detection?

Understanding PRRX1 expression patterns is essential for experimental design and selecting appropriate controls. Based on the available research, PRRX1 is detectable in:

• Mesenchymal tissues and progenitors:

  • PRRX1 regulates mesenchymal cell fate determination

  • The Prrx1 enhancer marks mesenchymal limb progenitors during development

  • Mesenchymal stem cells show detectable PRRX1 expression

• Dermal fibroblasts and wound healing contexts:

  • Adult dermal fibroblasts maintain an active Prrx1 enhancer, particularly in limb skin

  • PRRX1+ cells increase by approximately 16.5-fold in wounded dermis compared to unwounded contralateral dermis

  • PRRX1+ cells show differential distribution between papillary dermis and association with blood vessels

• Cancer cells with elevated expression:

  • Bladder cancer cell lines (T24, RT4, J82, SW780, 5637) show higher PRRX1 expression than normal bladder epithelial cells (HCV-29)

  • Colorectal cancer tissues and cell lines (SW480, HCT116) exhibit upregulated PRRX1 compared to normal epithelial tissues

  • Expression correlates with poor prognosis in these cancer types

• Other tissues with detectable expression:

  • Connective tissues including fascia and adipose tissue

  • Subcutaneous connective tissue surrounding muscle under wounded skin

  • Human testis tissue sections show positive staining with PRRX1 antibodies

• Tissues with minimal expression:

  • Back skin shows minimal PRRX1 enhancer activity with "no more than one or two Prrx1 enh+ cells in multiple sections of at least 4 mm"

This expression profile helps researchers select appropriate positive control tissues and cell types for antibody validation and experimental design.

How should researchers troubleshoot inconsistent subcellular localization patterns when using PRRX1 antibodies?

Inconsistent subcellular localization of PRRX1 between nuclear and cytoplasmic compartments requires systematic troubleshooting:

• Technical variables influencing localization detection:

  a) Fixation optimization:

  • Cross-linking fixatives (paraformaldehyde) may preserve nuclear architecture better than precipitating fixatives (methanol/acetone)

  • Overfixation can mask nuclear epitopes - test multiple fixation durations (10 minutes to 24 hours)

  • For cultured cells, compare immediate fixation versus PBS washes prior to fixation

  b) Permeabilization parameters:

  • Insufficient permeabilization may prevent antibody access to nuclear PRRX1

  • Compare different detergents: Triton X-100 (0.1-0.5%), Tween-20 (0.2-0.5%), or saponin (0.1-0.5%)

  • Increase permeabilization time for dense tissues or highly compact nuclei

  c) Antigen retrieval comparison:

  • Compare citrate buffer (pH 6.0) versus EDTA buffer (pH 9.0)

  • Optimize retrieval duration and temperature (microwave, pressure cooker, water bath)

  • For some nuclear antigens, combined heat and enzymatic retrieval may be necessary

• Biological variables affecting localization:

  a) Cell state considerations:

  • PRRX1 may shuttle between nucleus and cytoplasm depending on cell cycle phase

  • Compare serum-starved, confluent cells versus actively dividing cells

  • Assess localization in the context of specific signaling pathway activation (e.g., JAK2/STAT3 pathway implicated in search result )

  b) Isoform-specific localization:

  • The two PRRX1 isoforms (Prrx1a and Prrx1b) may exhibit different localization patterns

  • Use isoform-specific detection methods to determine if localization differences correlate with isoform expression

• Validation approaches:

  a) Multiple antibody comparison:

  • Test different antibody clones targeting distinct epitopes (e.g., OTI1E10, OTI6A4, OTI2B2)

  • Compare monoclonal antibodies with polyclonal antibodies

  • Verify that inconsistent localization is not antibody-specific

  b) Fractionation confirmation:

  • Perform subcellular fractionation followed by Western blotting

  • Compare nuclear, cytoplasmic, and membrane fractions

  • Use proper fraction markers (e.g., Lamin B for nuclear fraction, GAPDH for cytoplasmic fraction)

  c) Tagged protein visualization:

  • Express fluorescent protein-tagged PRRX1 constructs (GFP-PRRX1, mCherry-PRRX1)

  • Perform live-cell imaging to monitor localization without fixation artifacts

  • Compare localization of tagged proteins with antibody-based detection

These systematic approaches will help determine whether observed localization patterns reflect actual biology or technical artifacts in PRRX1 detection.

What experimental controls are critical when studying PRRX1's role in cancer stemness and chemoresistance?

When investigating PRRX1's involvement in cancer stemness and chemoresistance, as highlighted in search results and , the following controls are essential:

• Expression validation controls:

  a) Multiple detection methods:

  • Compare mRNA (RT-qPCR) and protein (Western blot, IHC) levels of PRRX1

  • Search result noted discrepancies between TCGA mRNA data and protein expression in bladder cancer

  • Quantify expression in matched patient samples (tumor vs. normal tissue)

  b) Cell line panels:

  • Include cell lines with varying endogenous PRRX1 levels

  • Search result showed differential expression across bladder cancer cell lines (T24, RT4, J82, SW780, 5637)

  • Verify expression in cancer stem cell-enriched populations (e.g., sphere cultures, CD44+/CD133+ sorted cells)

• Functional manipulation controls:

  a) Gene expression modulation:

  • Include both overexpression and knockdown/knockout models

  • Use inducible systems to control timing of PRRX1 modulation

  • Search result demonstrated effects of both "PRRX1 up-regulation" and "PRRX1 suppression"

  b) Rescue experiments:

  • After PRRX1 knockdown, reintroduce wild-type or mutant PRRX1

  • Test isoform-specific rescue with Prrx1a or Prrx1b separately

  • Search result showed "FOXM1 reversed the effects of PRRX1" - similar rescue approaches are valuable

• Chemoresistance-specific controls:

  a) Dose-response assessments:

  • Generate complete dose-response curves for chemotherapeutic agents

  • Calculate IC50 values as in search result : "IC50 assays showed that overexpressing PRRX1 remarkably reduced the sensitivity of SW480 cells to both 5-FU and L-OHP"

  • Compare multiple chemotherapeutic agents (e.g., 5-FU, L-OHP, gemcitabine)

  b) Cell death pathway controls:

  • Include apoptosis markers (cleaved PARP, cleaved caspases)

  • Assess alternative death mechanisms (necrosis, autophagy)

  • Search result showed PRRX1 "reduced gemcitabine-induced cytotoxicity by regulating the expression of the autophagy proteins LC3 and Beclin-1"

• Pathway analysis controls:

  a) Signaling pathway verification:

  • Include readouts of implicated pathways

  • Search result identified "JAK2/STAT3 signaling by targeting IL6" as a mechanism

  • Monitor phosphorylation status of pathway components (p-JAK2, p-STAT3)

  b) Inhibitor controls:

  • Use pathway-specific inhibitors as positive controls

  • Test whether pathway inhibition phenocopies PRRX1 modulation

  • Include concentration-matched vehicle controls

• In vivo validation controls:

  a) Tumor model selection:

  • Compare orthotopic models (as in search result ) with subcutaneous models

  • Include patient-derived xenografts when possible

  • Search result used "orthotopic xenograft CRC mouse model" to evaluate chemosensitivity

  b) Treatment regimen controls:

  • Include untreated, vehicle-treated, and standard-of-care groups

  • Monitor body weight and general health (search result noted "no significant difference of mice body weight was found between the 2 groups")

  • Document treatment schedule and dosing

What methodological approaches should be employed to investigate PRRX1's interaction with other transcription factors?

Based on search result , which demonstrated PRRX1 cooperates with FOXM1 to regulate downstream targets, the following methodological approaches are recommended for studying PRRX1's interactions with other transcription factors:

• Protein-protein interaction detection methods:

  a) Co-immunoprecipitation (Co-IP):

  • Immunoprecipitate PRRX1 using validated antibodies (such as those in search results )

  • Probe for interacting transcription factors in the precipitated material

  • Perform reciprocal IP (e.g., IP FOXM1 and probe for PRRX1)

  • Include appropriate negative controls (IgG, irrelevant antibody)

  b) Proximity ligation assay (PLA):

  • Enables visualization of protein interactions in situ with single-molecule sensitivity

  • Requires primary antibodies from different species against each interacting protein

  • Quantify interaction signals in different cellular compartments or tissue regions

  • Include negative controls (omitting one primary antibody)

  c) FRET/BRET approaches:

  • Express PRRX1 and potential interaction partners as fluorescent protein fusions

  • Measure energy transfer as indicator of protein proximity

  • Compare wild-type proteins with interaction-deficient mutants

• Transcriptional cooperation analysis:

  a) Chromatin immunoprecipitation (ChIP):

  • Perform ChIP-seq with PRRX1 antibodies to map genome-wide binding sites

  • Compare with binding profiles of potential interaction partners (e.g., FOXM1)

  • Search result showed PRRX1 and FOXM1 cooperatively regulate LC3 and Beclin-1

  • Perform sequential ChIP (re-ChIP) to confirm co-occupancy at specific loci

  b) Reporter gene assays:

  • Design luciferase reporters containing binding sites for both factors

  • Search result used "dual-luciferase reporter assays" to confirm PRRX1 binding to IL-6 promoter

  • Test synergistic activation by co-expressing PRRX1 with potential partners

  • Include binding site mutants as specificity controls

• Functional validation approaches:

  a) Gene expression analysis:

  • Compare transcriptional effects of individual versus combined knockdown/overexpression

  • Perform RNA-seq to identify synergistically regulated genes

  • Search result demonstrated that "FOXM1 reversed the effects of PRRX1" on gene expression

  • Validate key targets by RT-qPCR and protein analysis

  b) Phenotypic assays:

  • Assess biological outcomes relevant to the cellular context

  • For cancer studies, measure proliferation, migration, stemness, or chemoresistance

  • For developmental contexts, assess differentiation markers

  • Compare effects of individual versus combined factor manipulation

• Structural domain mapping:

  a) Deletion/mutation analysis:

  • Generate truncated versions of PRRX1 lacking specific domains

  • Test which regions are necessary for protein-protein interaction

  • Search result provides coding sequences for PRRX1 isoforms that could be modified

  • Create point mutations in predicted interaction interfaces

  b) Peptide array analysis:

  • Synthesize overlapping peptides covering PRRX1 sequence

  • Identify regions that directly interact with partner proteins

  • Validate identified motifs through targeted mutations

These methodological approaches provide a comprehensive toolkit for dissecting PRRX1's interactions with other transcription factors at molecular, genomic, and functional levels.

How should researchers approach the study of PRRX1 in wound healing and tissue regeneration?

Based primarily on search result , which characterizes PRRX1's role in injury response and wound healing, researchers should implement the following methodological approaches:

• Lineage tracing and genetic labeling strategies:

  a) Enhancer-driven reporter systems:

  • Search result utilized "Prrx1-creER-EGFP mice" to track PRRX1 enhancer activity

  • Tamoxifen-inducible systems allow temporal control of labeling

  • Label cells before injury to track existing PRRX1+ populations or during healing to identify newly activated cells

  b) Quantitative assessment:

  • Measure percentage of labeled cells in different tissue regions

  • Search result demonstrated "increase of Prrx1 enh+ from 0.37%±0.2 s.d. to 5.76%±3.8 s.d. of the total PRRX1+ cells" after injury

  • Track labeled cell distribution across healing phases (inflammatory, proliferative, remodeling)

• Tissue-specific injury models:

  a) Model selection rationale:

  • Search result revealed important differences between back skin and limb skin

  • "Prrx1 enhancer was shown to be active during wound healing and spike formation in Xenopus laevis, but absent in wound healing of mouse back skin"

  • Compare regenerative (limb) versus non-regenerative (back) contexts

  b) Standardized wounding procedures:

  • Full-thickness skin wounds of defined size (e.g., 2mm as used in search result )

  • Compare acute versus chronic wound models

  • Document healing kinetics through standardized photography and histology

• Cellular dynamics analysis:

  a) Cell migration tracking:

  • Monitor movement of labeled cells into wound bed

  • Search result showed Prrx1+ cells "migrate into the wound bed and proliferate"

  • Assess relationship with vasculature ("re-acquire an association with blood vessels")

  b) Cell fate determination:

  • Assess differentiation potential through co-staining with lineage markers

  • Search result demonstrated contribution to adipose tissue through "co-staining Prrx1 enh+ with a PERILIPIN antibody"

  • Track contribution to multiple wound healing cell types (fibroblasts, myofibroblasts, adipocytes)

• Molecular characterization:

  a) Temporal gene expression profiling:

  • Analyze PRRX1 target genes during different healing phases

  • Compare expression profiles between PRRX1+ and PRRX1- cells

  • Use sorted cells from reporter mice for population-specific analysis

  b) Signaling pathway assessment:

  • Evaluate potential crosstalk with known wound healing pathways (Wnt, TGF-β)

  • Apply knowledge from other contexts (e.g., search result linked PRRX1 to IL-6/JAK2/STAT3 signaling)

  • Test whether these pathways are active in wound healing PRRX1+ cells

• Functional perturbation approaches:

  a) Genetic manipulation strategies:

  • Conditional knockout of PRRX1 in specific cell populations

  • Inducible overexpression to boost PRRX1 activity during healing

  • Time-controlled manipulation to target specific healing phases

  b) Transplantation studies:

  • Isolate PRRX1+ cells and transplant into wounds

  • Compare healing outcomes with PRRX1- cell transplants

  • Assess integration and contribution to wound resolution

These approaches will enable comprehensive characterization of PRRX1's dynamics and functions during wound healing and tissue regeneration, building on the foundation established in search result .

What are the key considerations when selecting and validating PRRX1 antibodies for cancer research?

When selecting and validating PRRX1 antibodies for cancer research, particularly in studies of chemoresistance and stemness as described in search results and , researchers should consider:

• Context-specific expression validation:

  a) Cancer-type specific verification:

  • Validate antibodies in the specific cancer type under investigation

  • Search result demonstrated upregulation in bladder cancer

  • Search result showed increased expression in colorectal cancer

  • Verify detection in both cell lines and patient-derived tissues

  b) Expression level considerations:

  • Select antibodies with appropriate sensitivity for expected expression levels

  • High-affinity monoclonal antibodies for low expression contexts

  • Search result noted "PRRX1 was highly expressed in BC tissues and cells"

• Correlation with functional markers:

  a) Co-detection with stemness markers:

  • Validate antibodies for compatibility with stem cell marker co-staining

  • Search result linked PRRX1 to "stemness acquirement" in colorectal cancer

  • Select antibodies that work in multiplexed IHC/IF protocols

  b) Pathway component detection:

  • Validate compatibility with antibodies against pathway components

  • Search result showed PRRX1 cooperates with FOXM1

  • Search result demonstrated PRRX1 activates "JAK2/STAT3 signaling by targeting IL-6"

  • Choose antibodies raised in different species to facilitate co-staining

• Technical validation parameters:

  a) Application-specific validation:

  • For patient prognosis studies: Validate for IHC on FFPE tissues

  • For mechanism studies: Validate for IF/ICC and WB

  • For chromatin studies: Validate for ChIP applications

  • Search result used multiple techniques including Western blot, immunofluorescence, and dual-luciferase assays

  b) Reproducibility assessment:

  • Test lot-to-lot consistency with standardized positive controls

  • Use xenograft tumors with manipulated PRRX1 levels as controls

  • Compare staining patterns across technical and biological replicates

• Functional validation approaches:

  a) Expression-manipulation controls:

  • Validate antibody signal in PRRX1 overexpression models

  • Confirm signal reduction in knockdown/knockout models

  • Search results used both overexpression and knockdown approaches

  b) Isoform-specific considerations:

  • Determine whether cancer-specific functions are isoform-dependent

  • Select antibodies that can distinguish Prrx1a and Prrx1b if relevant

  • Search result provides information on the distinct isoforms

• Clinical correlation validation:

  a) Prognostic significance verification:

  • Validate antibodies in tissues with known outcome data

  • Search result found "high expression of PRRX1 was tightly associated with the metastasis, chemoresistance, and poor prognosis of CRC patients"

  • Confirm correlation between antibody staining intensity and patient outcomes

  b) Treatment response prediction:

  • Validate in pre- and post-treatment samples when available

  • Search result demonstrated PRRX1 "weakened gemcitabine-induced cytotoxicity"

  • Search result showed PRRX1 "enhanced the resistance of CRC cells to 5-FU and L-OHP"

These considerations will ensure selection of appropriate antibodies for cancer research applications and strengthen the reliability of findings regarding PRRX1's role in cancer biology.