gse1 Antibody

What is GSE1 and why is it important in molecular biology research?

GSE1 (Genetic Suppressor Element 1, also known as KIAA0182) is a proline-rich protein with coiled-coil domains that functions as a subunit of the BRAF35-HDAC (BHC) histone deacetylase complex. In humans, the canonical GSE1 protein comprises 1217 amino acid residues with a molecular mass of 136.2 kDa . Recent research has revealed that GSE1 forms a complex with the HDAC1/CoREST deacetylase/demethylase co-repressor complex and plays a crucial role in the DNA damage response (DDR) .

GSE1 has gained significant research interest due to its emerging role in cancer biology. It functions as an oncogene in several cancer types, including breast, gastric, and prostate cancers, where its overexpression correlates with poor prognosis, increased metastasis, therapy resistance, and disease recurrence .

For researchers, GSE1 represents an important target for studying chromatin regulation, DNA damage response pathways, and cancer progression mechanisms.

How should researchers select the appropriate GSE1 antibody for their specific experimental needs?

Selection of the appropriate GSE1 antibody depends on several experimental factors:

Application considerations:

• For Western blotting: Both polyclonal and monoclonal antibodies work well, with monoclonal antibodies (like Santa Cruz G-6) offering high specificity .

• For immunoprecipitation: Monoclonal antibodies conjugated to agarose beads are recommended (e.g., GSE1 Antibody G-6 AC) .

• For immunofluorescence: Fluorochrome-conjugated antibodies or unconjugated primary antibodies with fluorescent secondary antibodies work effectively .

• For immunohistochemistry: Rabbit polyclonal antibodies (such as those from Atlas Antibodies) are often preferred due to their high sensitivity in tissue sections .

Species reactivity: Ensure the antibody recognizes GSE1 in your species of interest. Many commercially available antibodies react with human, mouse, and rat GSE1, while some also recognize other species like zebrafish . For cross-species studies, select antibodies with confirmed reactivity across your target species.

Isoform detection: GSE1 has up to three different reported isoforms. Confirm which isoforms your selected antibody can detect, especially if your research focuses on isoform-specific functions .

Validation evidence: Request validation data including Western blots showing the expected 136.2 kDa band and IHC/IF images demonstrating appropriate cellular localization. Published literature citing the specific antibody provides additional confidence in its performance .

What are the optimal conditions for using GSE1 antibodies in Western blotting applications?

Optimizing Western blotting conditions for GSE1 detection requires attention to several key parameters:

Sample preparation:

• Use RIPA buffer supplemented with protease inhibitors for efficient extraction of GSE1

• Sonicate lysates briefly (3 × 10s pulses) to ensure complete protein solubilization

• Include phosphatase inhibitors if studying GSE1 phosphorylation states

Gel electrophoresis and transfer:

• Use 6-8% polyacrylamide gels due to GSE1's large size (136.2 kDa)

• Extend transfer time to 2 hours at 80V or perform overnight transfer at 30V (4°C) to ensure complete transfer of large protein

Antibody incubation:

• Primary antibody dilutions typically range from 1:500 to 1:1000 for commercial GSE1 antibodies

• For GSE1 monoclonal antibody (G-6), the recommended dilution is 1:1000 in 5% non-fat dry milk

• For polyclonal antibodies, dilutions of 1:500 in 5% BSA often yield optimal results

• Incubate primary antibody overnight at 4°C for best signal-to-noise ratio

Detection optimization:

• ECL-based detection systems work well for GSE1

• For weaker signals, consider using high-sensitivity ECL substrates or signal amplification systems

• Membrane stripping for reprobing should be gentle to preserve epitope integrity

Based on published research, researchers have successfully used HDAC1 SAT 208 (polyclonal rabbit, 1:10,000) alongside GSE1 antibodies (Proteintech, 24947-1-AP, 1:1000) to study GSE1-HDAC1 interactions .

How can GSE1 antibodies be effectively used for immunohistochemistry in cancer tissue samples?

For effective immunohistochemical detection of GSE1 in cancer tissues, follow these research-validated protocols:

Tissue preparation:

• Fix tissues in 10% neutral-buffered formalin for 24-48 hours

• Process and embed in paraffin following standard histology protocols

• Cut sections at 4-5 μm thickness for optimal antibody penetration

Antigen retrieval optimization:

• Heat-induced epitope retrieval (HIER) using citrate buffer (pH 6.0) for 20 minutes provides optimal results for most GSE1 antibodies

• Allow slides to cool in retrieval solution for 20 minutes before proceeding

Antibody incubation parameters:

• Block endogenous peroxidase activity with 3% H₂O₂ for 10 minutes

• Apply protein block (e.g., 5% normal goat serum) for 30 minutes

• Use GSE1 antibodies at dilutions of 1:100 to 1:200

• Incubate primary antibody overnight at 4°C in a humidified chamber

Signal detection and scoring:

• Use polymer-based detection systems for enhanced sensitivity

• Counterstain with hematoxylin for nuclear visualization

• For scoring, assess both staining intensity and percentage of positive cells

In published research on GSE1 in gastric cancer, investigators classified tissues as "GSE1 high" when ≥10% of cells showed positive staining and "GSE1 low" when <10% showed positive staining . This scoring system correlated with clinical features including lymph node metastasis and clinical stage.

In prostate cancer studies, researchers quantified immunoreactivity by analyzing:

• Total stained area

• Stained cell count

• Average size of stained area

• Percentage stained area

• Perimeter measurements

These parameters were quantified using NIH ImageJ software, providing a comprehensive assessment of GSE1 expression patterns .

What are common issues when using GSE1 antibodies and how can researchers address them?

Issue: High background in Western blots

• Solution: Increase blocking time to 2 hours at room temperature using 5% non-fat dry milk

• Solution: Reduce primary antibody concentration (try 1:1500 instead of 1:1000)

• Solution: Add 0.1% Tween-20 to washing buffer and increase wash times (5 × 5 minutes)

Issue: Weak or absent GSE1 signal

• Solution: Verify protein extraction efficiency; GSE1 may require stronger lysis conditions

• Solution: Increase protein loading to 50-80 μg per lane for detection of endogenous GSE1

• Solution: For overexpressed GSE1, 10-20 μg protein per lane is typically sufficient

• Solution: Extend primary antibody incubation to overnight at 4°C

• Solution: Try different GSE1 antibodies that recognize different epitopes

Issue: Multiple bands in Western blot

• Solution: Verify if bands correspond to known GSE1 isoforms (up to 3 reported)

• Solution: Increase gel percentage to improve resolution of large proteins

• Solution: Include phosphatase inhibitors if bands represent phosphorylated forms

• Solution: Validate specificity using GSE1 knockdown controls

Issue: Weak immunohistochemical staining

• Solution: Optimize antigen retrieval methods (try EDTA buffer pH 9.0 as alternative)

• Solution: Extend primary antibody incubation time to overnight at 4°C

• Solution: Use amplification steps such as avidin-biotin complex method

• Solution: Ensure tissue fixation is not excessive (over-fixation can mask epitopes)

Issue: Non-specific binding in immunofluorescence

• Solution: Use stronger blocking (5% BSA + 5% normal serum from secondary antibody species)

• Solution: Include 0.3% Triton X-100 in blocking buffer for better penetration

• Solution: Pre-adsorb secondary antibody with tissue powder

• Solution: Include additional washing steps with PBS + 0.1% Tween-20

How can researchers validate GSE1 antibody specificity for their experimental systems?

Rigorous validation of GSE1 antibody specificity is essential for generating reliable research data. Implement these validation strategies:

Genetic knockdown/knockout validation:

• Perform siRNA or shRNA-mediated knockdown of GSE1

• Use established protocols like those published for gastric cancer cells: "shGSE1, 5′-GCCUACAUCUAUGAUGAGUTT-3′ was used for GSE1 depletion"

• Compare antibody signal between wild-type and GSE1-depleted samples

• Successful knockdown should significantly reduce or eliminate specific signal

Overexpression validation:

• Transfect cells with GSE1 expression vectors

• Compare antibody signal between untransfected and GSE1-overexpressing cells

• Signal intensity should increase proportionally to GSE1 expression levels

Peptide competition assay:

• Pre-incubate antibody with excess immunizing peptide

• Apply mixture to duplicate samples in parallel with untreated antibody

• Specific signals should be abolished or significantly reduced by peptide competition

Orthogonal technique validation:

• Verify protein expression using alternative methods (e.g., mass spectrometry)

• Compare protein levels with mRNA expression data

• Concordance between different measurement approaches supports antibody specificity

Epitope mapping:

• If working with multiple antibodies, use those recognizing different GSE1 epitopes

• Similar staining patterns with different antibodies increase confidence in specificity

• Document epitope location and potential post-translational modifications that might affect binding

How can GSE1 antibodies be used to investigate protein-protein interactions within chromatin-modifying complexes?

GSE1 antibodies are valuable tools for exploring protein-protein interactions within chromatin-modifying complexes, particularly the HDAC1/CoREST complex. The following methodological approaches have proven effective:

Co-immunoprecipitation (Co-IP):

• Lyse cells in buffer containing 50 mM Tris-HCl pH 7.5, 150 mM NaCl, 1% NP-40, 0.5% sodium deoxycholate, and protease inhibitors

• Perform immunoprecipitation using 2-5 μg of GSE1 antibody conjugated to protein A/G beads

• Incubate overnight at 4°C with gentle rotation

• Analyze precipitated complexes by SDS-PAGE and immunoblotting for suspected interaction partners (HDAC1, CoREST, LSD1, USP22)

Proximity ligation assay (PLA):

• Fix cells with 4% paraformaldehyde for 15 minutes

• Permeabilize with 0.1% Triton X-100 for 10 minutes

• Incubate with GSE1 antibody and antibody against suspected interaction partner

• Perform PLA following manufacturer's protocol

• Analyze fluorescent signals representing protein-protein interactions within 40 nm proximity

Chromatin immunoprecipitation (ChIP):

• Cross-link protein-DNA complexes with 1% formaldehyde for 10 minutes

• Sonicate chromatin to 200-500 bp fragments

• Immunoprecipitate with GSE1 antibody

• Analyze precipitated DNA by qPCR or sequencing

• Compare GSE1 binding sites with those of HDAC1/CoREST complex components

Sequential ChIP (Re-ChIP):

• Perform first ChIP with GSE1 antibody

• Elute complexes under non-denaturing conditions

• Perform second ChIP with antibody against suspected interaction partner

• This approach identifies genomic loci where both proteins co-localize

Recent research has demonstrated that "GSE1 forms a complex with the HDAC1/CoREST deacetylase/demethylase co-repressor complex" and "GSE1 appears to be essential for binding of the deubiquitinase USP22 to CoREST" . These findings highlight the importance of GSE1 in recruiting specific proteins to chromatin-modifying complexes.

What are the emerging approaches for studying GSE1's role in the DNA damage response using specific antibodies?

Recent publications have revealed GSE1's significant role in the DNA damage response (DDR). Researchers can employ these advanced techniques using GSE1 antibodies:

Laser microirradiation and real-time imaging:

• Grow cells on glass-bottom dishes

• Sensitize with Hoechst 33342 (10 μg/ml, 10 minutes)

• Perform laser microirradiation to induce localized DNA damage

• Track recruitment of fluorescently-tagged GSE1 or use immunofluorescence with GSE1 antibodies

• Quantify recruitment kinetics relative to known DDR factors

Proximity-dependent biotin identification (BioID):

• Generate GSE1-BioID fusion constructs

• Express in cells and provide biotin supplement

• Extract biotinylated proteins using streptavidin pull-down

• Identify GSE1-proximal proteins during normal conditions and after DNA damage

• Compare protein interaction networks under different DNA-damaging conditions

Phosphoproteome analysis after GSE1 manipulation:

• Research has shown that "loss of GSE1 results in impaired DDR, ATR signalling and γH2AX formation upon DNA damage induction"

• Compare phosphorylation of DDR proteins between wild-type and GSE1-depleted cells

• Focus on "ATR target serine-glutamine motifs (SQ) on DDR-related hallmark proteins"

• Analyze samples by mass spectrometry for comprehensive phosphoproteome analysis

• Use phospho-specific antibodies against key DDR factors for targeted analysis

Chromatin fractionation and histone modification analysis:

• Separate chromatin fractions from nuclear soluble proteins

• Analyze histone modifications (particularly H2B K120 ubiquitination) in GSE1-depleted cells

• Research has established that "GSE1 is essential for binding of the deubiquitinase USP22 to CoREST and for the deubiquitination of H2B K120 in response to DNA damage"

• Compare modification patterns before and after DNA damage induction

• Correlate changes with γH2AX formation and downstream repair processes

How can researchers use GSE1 antibodies to investigate its role in cancer progression and therapy resistance?

GSE1 has emerged as an important factor in cancer progression and therapy resistance. Researchers can employ these methodological approaches using GSE1 antibodies:

Tissue microarray (TMA) analysis:

• Construct TMAs containing multiple patient samples

• Perform immunohistochemistry using optimized GSE1 antibody protocols

• Score GSE1 expression levels (high vs. low) based on established thresholds

• Correlate with clinicopathological features and patient outcomes

In gastric cancer research, "GSE1 was associated with a high risk of tumor lymph node metastasis and higher clinical stage in HER2-positive gastric cancer patients" . Similarly, in prostate cancer studies, "Patients with GSE1high TACSTD2low expression are more prone to recurrence and disease-specific death than their GSE1lowTACSTD2high counterparts" .

Therapy resistance models:

• Generate therapy-resistant cancer cell lines (e.g., trastuzumab-resistant gastric cancer cells, castration-resistant prostate cancer cells)

• Compare GSE1 expression between parental and resistant cells using Western blot

• Research has shown that "trastuzumab-resistant gastric cancer cells overexpressed GSE1" and that targeting GSE1 "is a workable therapeutic strategy for inhibiting androgen-driven oncogenic signals, re-sensitizing CRPC to treatment"

Patient-derived xenograft (PDX) models:

• Establish PDX models from therapy-resistant tumors

• Analyze GSE1 expression by immunohistochemistry and Western blot

• Correlate expression with drug response profiles

• Test GSE1 depletion strategies in PDX models to assess re-sensitization to therapy

Functional studies with GSE1 manipulation:

• Use validated shRNA sequences for GSE1 knockdown: "5′-GCCUACAUCUAUGAUGAGUTT-3′"

• Assess therapy response before and after GSE1 knockdown

• Measure cell viability, 3D growth, migration, and invasion

• Analyze downstream pathways affected by GSE1 manipulation

Research has demonstrated that "depletion of GSE1 decreased the trastuzumab resistance of trastuzumab-resistant gastric cancer cells" and that "the shRNA-mediated targeting of GSE1 (shGSE1) significantly inhibits cell proliferation and attenuates cell migration and tumorsphere formation in metastatic PC3 and DU145 cell lines" .

What methodological considerations should researchers take when analyzing GSE1 expression in clinical samples?

When analyzing GSE1 expression in clinical samples, researchers should implement these methodological approaches to ensure reliable and clinically relevant results:

Sample collection and preservation:

• Collect fresh tissue when possible for optimal protein preservation

• Fix samples consistently (10% neutral-buffered formalin for 24-48 hours)

• Include normal adjacent tissue as controls

• Document clinical information including treatment history, response, and outcomes

Staining protocol standardization:

• Use consistent antibody dilutions across all samples (typically 1:100-1:200)

• Include positive and negative controls in each staining batch

• Use automated staining platforms when possible to reduce variability

• Document lot numbers of antibodies and reagents

Scoring and quantification:

• Implement standardized scoring systems for consistency

• In published studies on HER2-positive gastric cancer, "positive-stained cells 10% or more than 10% were designated to be GSE1 high, and positive-stained cells less than 10% were designated to be GSE1 low"

• In prostate cancer research, multiple parameters were assessed: "total stained area, stained cell count, average size of the stained area, percentage stained area, and perimeter"

• Use digital pathology and image analysis software (e.g., NIH ImageJ) for objective quantification

Correlation with clinical and molecular features:

• Associate GSE1 expression patterns with:

  • Patient demographics

  • Tumor stage and grade

  • Metastatic status

  • Treatment response

  • Survival outcomes

• Conduct multivariate analyses to assess GSE1 as an independent prognostic factor

Integrated multi-omics analyses:

• Combine protein expression data with:

  • Genomic alterations

  • Transcriptomic profiles

  • Epigenetic modifications

• Assess GSE1 in the context of related pathways (e.g., HDAC1/CoREST complex, DNA damage response)

In published research, these methodologies have revealed important clinical correlations: "high levels of GSE1 were statistically correlated with a high risk of tumor lymph node metastasis" and "The GSE1–TACSTD2 expression profile is associated with the therapy responses and clinical outcomes in patients with PCa, especially those with metastatic/recurrent disease" .

How can GSE1 antibodies be utilized to study its role in the USP22-GSE1-CoREST multi-enzymatic complex?

Recent research has identified GSE1 as a critical component of the USP22-GSE1-CoREST multi-enzymatic complex, which combines "deacetylase, demethylase, and deubiquitinase activity" . Researchers can leverage these methodological approaches:

Co-localization studies:

• Perform triple immunofluorescence staining using antibodies against:

  • GSE1 (e.g., Proteintech, 24947-1-AP, 1:1000)

  • USP22 (e.g., Novus Biologicals, NBP1-49644, 1:1000)

  • CoREST components (e.g., Millipore, 07-455, 1:1000)

• Analyze co-localization particularly after DNA damage induction

• Quantify Pearson's correlation coefficients for spatial association

Enzymatic activity assays:

• Immunoprecipitate complexes using GSE1 antibodies

• Measure deacetylase activity using fluorogenic HDAC substrates

• Assess demethylase activity using specific methylated peptide substrates

• Quantify deubiquitinase activity using ubiquitin-AMC or Ub-CHOP reporter assays

• Compare enzyme activities between wild-type and GSE1-depleted samples

Histone modification analysis:

• Research has established that "loss of GSE1 inhibits deubiquitination of histone H2B at lysine 120"

• Extract histones using acid extraction protocols

• Analyze specific histone modifications by Western blotting or mass spectrometry

• Focus particularly on H2B K120 ubiquitination states

• Compare modification patterns before and after DNA damage

Structure-function analysis:

• Generate GSE1 domain deletion constructs

• Assess which domains are required for:

  • USP22 recruitment

  • CoREST complex association

  • Functional deubiquitination of H2B K120

• Use co-immunoprecipitation and functional assays to map interaction domains

What are the cutting-edge techniques for studying GSE1's potential as a therapeutic target in cancer?

As GSE1 emerges as a potential therapeutic target in multiple cancer types, researchers can employ these advanced techniques:

CRISPR-Cas9 genome editing:

• Generate GSE1 knockout cancer cell lines

• Compare drug sensitivity profiles between wild-type and knockout cells

• Perform rescue experiments with wild-type or mutant GSE1

• Analyze downstream signaling pathways affected by GSE1 deletion

Patient-derived organoids (PDOs):

• Establish 3D organoid cultures from patient tumors

• Compare GSE1 expression between organoids and parent tumors

• Test GSE1 targeting strategies in organoids

• Assess therapy response before and after GSE1 manipulation

Small molecule inhibitor screening:

• Develop high-throughput screening assays targeting:

  • GSE1 protein-protein interactions

  • GSE1-dependent enzymatic activities

  • GSE1 expression regulation

• Validate hits using biochemical and cellular assays

• Assess synergy with established cancer therapeutics

Combination therapy approaches:

• Research has shown that "shGSE1 enhances sensitivity to the antiandrogens abiraterone and enzalutamide in vitro and in vivo"

• Test combinations of GSE1 inhibition with:

  • Targeted therapies (e.g., trastuzumab, antiandrogens)

  • DNA-damaging agents

  • Epigenetic modulators

• Determine optimal sequencing and dosing strategies

Biomarker development:

• Develop robust IHC protocols for GSE1 detection in FFPE samples

• Create companion diagnostic assays for potential GSE1-targeting therapies

• Evaluate GSE1 expression patterns as predictive biomarkers for existing therapies

• Establish cutoff values that correlate with clinical outcomes