ELF5 Antibody

What is ELF5 and what cellular processes does it regulate?

ELF5 (E74-like factor 5) is a transcription factor belonging to the Ets family with a highly conserved carboxy-terminal domain that facilitates DNA binding, which is essential for its transcriptional regulatory functions . ELF5 plays crucial roles in:

• Regulation of gene expression during development and differentiation

• Keratinocyte proliferation and differentiation processes

• Trophoblast stem cell maintenance and differentiation

• Mammary gland development and alveologenesis

• Inhibition of epithelial-mesenchymal transition (EMT)

• Principal cell lineage determination

ELF5 demonstrates remarkable context-dependent functions, acting as both a tumor suppressor in some cancer types and as a carcinogenic factor in others, particularly in different breast cancer subtypes .

What types of ELF5 antibodies are available for research applications?

Researchers can select from several ELF5 antibody types depending on their experimental needs:

When selecting an antibody, researchers should consider the specific application requirements, target species, and whether post-translational modifications of ELF5 are relevant to their research question .

What tissues or cell types serve as effective positive controls for ELF5 antibody validation?

Based on published literature, reliable positive controls include:

• T47D breast cancer cells: Express high endogenous ELF5 levels

• HEK293T cells: Show significant ELF5 expression

• Trophoblast stem cells: Where ELF5 plays critical regulatory roles

• CD34+ hair follicle stem cells: Show elevated Elf5 expression compared to CD34- populations

• Mammary epithelial cells: Particularly during pregnancy and lactation phases

• Keratinocytes: Where ELF5 regulates terminal differentiation

Conversely, Hela cells have been reported to show no detectable ELF5 expression and can serve as negative controls . For tissue sections, colorectal and cervical cancer samples have been verified for immunohistochemical detection .

What are optimized protocols for detecting ELF5 by Western blotting?

For reliable Western blot detection of ELF5:

Sample preparation:

• Use nuclear extraction protocols as ELF5 is predominantly nuclear

• Include protease inhibitors and phosphatase inhibitors to preserve post-translational modifications

• T47D cells serve as excellent positive controls

Electrophoresis and transfer parameters:

• Load 20-50 μg of nuclear protein extract

• Use 10-12% SDS-PAGE gels for optimal resolution around the 30-31 kDa range

• Transfer to PVDF membranes at 100V for 60-90 minutes or overnight at 30V

Antibody conditions:

• Recommended dilutions typically range from 1:500-1:1000 for primary antibody

• Incubate overnight at 4°C for optimal binding

• For monoclonal antibodies like ELF5 (C-1), appropriate secondary antibodies include HRP-conjugated anti-mouse IgG

Expected results:

• The calculated molecular weight of human ELF5 is approximately 30-31 kDa

• Observed molecular weight may vary slightly depending on post-translational modifications, particularly acetylation

How should researchers optimize immunofluorescence protocols for ELF5 detection?

For successful immunofluorescence detection of nuclear ELF5:

Fixation and permeabilization:

• 4% paraformaldehyde fixation for 15-20 minutes provides good epitope preservation

• 0.1% Triton X-100 permeabilization is essential for nuclear antigen access

Blocking and antibody incubation:

• Block with 5-10% serum matching the secondary antibody host species

• Dilute primary antibodies in the range of 1:50-1:200 , or use at 4 μg/ml concentration

• Incubate overnight at 4°C in a humidified chamber

Visualization and controls:

• Use high-quality fluorophore-conjugated secondary antibodies

• Include DAPI nuclear counterstain to confirm nuclear localization

• Acquire z-stack images to properly visualize nuclear signals

• Include antibody omission controls and ideally knockdown/knockout validation samples

What approaches effectively demonstrate ELF5's protein-protein interactions?

For investigating ELF5's interactions with other proteins:

Co-immunoprecipitation strategies:

• Use mild lysis buffers (150-300 mM NaCl) to preserve nuclear protein interactions

• Pre-clear lysates to reduce non-specific binding

• For each immunoprecipitation, use 2-5 μg of antibody per 500-1000 μg of protein lysate

Validated interaction partners to investigate:

• p300 acetyltransferase: Demonstrated to interact with and acetylate ELF5

• Eomes and Tfap2c: Form stage-specific complexes with ELF5 in trophoblast stem cells

• Androgen receptor (AR): ELF5 has been shown to bind to AR in prostate cancer cells

Verification approaches:

• Confirm interactions through reciprocal co-IPs

• Endogenous protein interactions have been successfully demonstrated between ELF5 and p300 in T47D cells

• When performing co-IP with overexpressed proteins, GFP-tagged ELF5 and HA-tagged interaction partners have been successfully used

How can researchers investigate ELF5's role in epithelial-mesenchymal transition (EMT)?

For studying ELF5's function in EMT inhibition:

Experimental models:

• TGFβ-induced EMT in mammary epithelial cell lines (e.g., NMuMG cells)

• ELF5 overexpression models using HA-tagged ELF5 constructs

• Breast cancer cell lines with varying ELF5 expression levels

Key analytical approaches:

• Immunofluorescence co-staining of ELF5 with epithelial markers (E-cadherin) and mesenchymal markers (Vimentin)

• Western blot analysis of EMT markers following ELF5 modulation

• ChIP assays to confirm direct binding of ELF5 to the Snail2 (Slug) promoter

• Migration and invasion assays in cells with altered ELF5 expression

Critical findings to validate:

• ELF5 overexpression prevents TGFβ-induced loss of E-cadherin expression

• ELF5 directly represses transcription of Snail2/Slug, a master regulator of EMT

• Correlation between ELF5 levels and epithelial morphology in 3D culture systems

What methods are effective for studying ELF5 acetylation and its functional consequences?

To investigate the critical role of ELF5 acetylation:

Detection methods:

• Immunoprecipitation with ELF5 antibodies followed by Western blot with anti-acetyl-lysine antibodies

• Reciprocal approach: IP with anti-acetyl-lysine antibodies followed by ELF5 detection

Functional analysis approaches:

• Acetylation promotes ELF5 ubiquitination and degradation while also being essential for its antiproliferative effects in breast cancer

• Compare wildtype versus acetylation-deficient ELF5 in:

  • Luciferase reporter assays (particularly for CCND1 promoter activity)

  • Protein stability assessment following cycloheximide treatment

  • Ubiquitination analysis

Context-dependent considerations:

• Acetylation status affects ELF5's role in different breast cancer subtypes

• p300 interaction should be assessed as it has been identified as an ELF5 binding partner

How can ELF5 antibodies help distinguish its context-dependent roles in stem cell maintenance versus differentiation?

For analyzing ELF5's dual roles in stemness and differentiation:

Stem cell systems to investigate:

• Trophoblast stem cells: ELF5 acts as a molecular switch governing the balance between proliferation and differentiation

• Hair follicle stem cells: CD34+ cells show higher ELF5 expression compared to CD34- cells

• Epidermal stem cells: Both loss and gain of ELF5 function affect colony formation

Analytical approaches:

• Colony forming assays following ELF5 knockdown or overexpression

• ChIP-seq analysis to identify differential binding patterns in stem vs. differentiating cells

• Analyze stoichiometry-sensitive interactions with other transcription factors:

  • In trophoblast stem cells, ELF5 preferentially binds Eomes

  • During differentiation, ELF5's interaction shifts toward Tfap2c

Key experimental observations:

• In trophoblast cells, increasing ELF5 levels trigger differentiation through stoichiometry-dependent interactions

• In epidermal stem cells, both loss and gain of ELF5 function reduce colony formation

• In hair follicle stem cells, both ELF5 knockdown and overexpression increase colony formation

Why might ELF5 detection be inconsistent across different tissue types?

Several factors can contribute to variable ELF5 detection:

Technical factors:

• Fixation effects: Overfixation can mask epitopes; optimize fixation time (12-24h)

• Antigen retrieval requirements: Different tissues may require citrate buffer (pH 6.0) or EDTA buffer (pH 8.0-9.0)

• Antibody penetration: Dense tissues may require extended incubation times

Biological considerations:

• ELF5 expression varies dramatically across tissues and developmental stages

• Alternative splicing produces different isoforms that may not be recognized by all antibodies

• Post-translational modifications (particularly acetylation) may mask epitopes

Protocol adjustments:

• For IHC applications, dilution ranges of 1:50-1:200 have been validated

• For dense tissues, consider signal amplification systems

• Test multiple antibodies targeting different ELF5 epitopes

How can researchers reconcile conflicting results from different ELF5 antibodies?

When facing discrepancies between antibodies:

Epitope analysis:

• Map the epitopes recognized by different antibodies

• Determine if epitopes might be masked by protein interactions or modifications

• The C-terminal DNA-binding domain is highly conserved among Ets family members , potentially leading to cross-reactivity

Validation steps:

• Use genetic models (knockdown/knockout) to confirm specificity

• Test antibodies in overexpression systems with tagged ELF5

• Consider isoform-specific detection - several alternatively spliced transcript variants encoding different isoforms have been described

Integration approach:

• Use multiple antibodies targeting different regions when possible

• Correlate with mRNA expression data

• Present results with clear indication of which antibody was used and its target epitope

What strategies overcome weak signal issues when detecting ELF5 in certain cell types?

For enhancing ELF5 detection sensitivity:

Sample optimization:

• For Western blot, nuclear extraction is essential as ELF5 is a nuclear transcription factor

• For tissue sections, freshly prepared samples often provide better results than archived materials

• Consider using cell lines with known high ELF5 expression (T47D, HEK293T) as positive controls

Protocol enhancements:

• Extended primary antibody incubation (overnight at 4°C)

• Optimized antigen retrieval methods specific to tissue type

• Signal amplification systems for low-expressing samples

Alternative approaches:

• If protein detection is challenging, correlate with mRNA expression

• For breast tissue, ELF5 has been characterized as a "biological clock" indicating tissue age and cancer risk

• Consider examining both acetylated and non-acetylated forms, as acetylation significantly affects ELF5 function

How can ELF5 antibodies contribute to understanding cancer subtype heterogeneity?

ELF5 shows remarkable context-dependent functions across cancer subtypes:

Breast cancer applications:

• In luminal A breast cancer subtypes, ELF5 inhibits proliferation

• In basal-like breast cancer, ELF5 promotes cell proliferation

• ELF5 can drive a basal-like signature in luminal cancer, leading to estrogen insensitivity

Prostate cancer research:

• ELF5 acts as an antioncogene in prostate cancer

• ELF5 interacts with androgen receptor (AR) as a physiological partner and negatively regulates its transcriptional activity

• ELF5 prevents epithelial-mesenchymal transition and metastasis in prostate cancer

Methodological approaches:

• Multiplex immunofluorescence to correlate ELF5 with subtype-specific markers

• ChIP-seq to compare genomic binding patterns between subtypes

• Co-IP to identify subtype-specific interaction partners

• Correlation with clinical outcomes in subtype-specific patient cohorts

What are the latest approaches for studying ELF5's role in therapeutic resistance?

For investigating ELF5's role in treatment response:

Endocrine resistance in breast cancer:

• Tamoxifen-resistant luminal cancer cell lines show increased ELF5 expression

• ELF5 can rewire FOXA1 and ER transcriptional networks to drive estrogen insensitivity

Experimental approaches:

• Compare ELF5 expression and acetylation status before and after resistance development

• ChIP-seq to identify altered binding patterns in resistant versus sensitive cells

• Immunoprecipitation to analyze changes in protein interaction networks

• Correlate ELF5 levels with treatment response in patient samples

Potential therapeutic implications:

• ELF5 could potentially serve as a biomarker for endocrine therapy resistance

• Targeting ELF5 or its acetylation might represent a strategy to overcome resistance

• Understanding ELF5's "biological clock" function may help refine prevention trial cohorts