SUPT4H1 Antibody

What is SUPT4H1 and why is it important in cellular processes?

SUPT4H1 (Suppressor of Ty 4 Homolog 1) is the small subunit of the DRB sensitivity-inducing factor (DSIF) complex, which plays a crucial role in regulating mRNA processing and transcription elongation by RNA polymerase II. The protein is localized to the nucleus and interacts with the large subunit (SUPT5H) to form the functional DSIF complex . The DSIF complex positively regulates mRNA capping by stimulating the mRNA guanylyltransferase activity of RNGTT/CAP1A. Additionally, it cooperates with the negative elongation factor complex (NELF) to enhance transcriptional pausing at promoter-proximal sites, which facilitates the assembly of elongation-competent RNA polymerase II complexes .

SUPT4H1 is particularly important because it can both positively and negatively regulate transcriptional elongation, depending on the context. For example, it is required for efficient activation of transcriptional elongation by the HIV-1 nuclear transcriptional activator Tat, where it suppresses transcriptional pausing in transcripts derived from the HIV-1 LTR . This dual regulatory role makes SUPT4H1 a significant target for studying fundamental transcription mechanisms.

What types of SUPT4H1 antibodies are available for research?

Multiple types of SUPT4H1 antibodies are currently available for research applications, varying in host species, clonality, and target epitopes:

Researchers should select antibodies based on their specific experimental requirements, considering factors such as the epitope location, application compatibility, and species cross-reactivity .

What are the common applications for SUPT4H1 antibodies?

SUPT4H1 antibodies are employed in multiple research applications, each with specific protocols and considerations:

• Western Blotting (WB): Most commonly used to detect SUPT4H1 protein expression levels. The observed molecular weight is approximately 14 kDa, which aligns with the calculated molecular weight of 13 kDa . Recommended dilutions typically range from 1:500 to 1:2000 depending on the antibody specificity and sample type .

• Enzyme-Linked Immunosorbent Assay (ELISA): Useful for quantitative detection of SUPT4H1 in protein lysates. This method provides higher sensitivity compared to Western blotting for specific applications .

• Immunohistochemistry (IHC): Applied to detect SUPT4H1 in tissue sections, allowing researchers to analyze its localization and expression patterns in different cellular compartments, particularly within the nucleus where SUPT4H1 primarily functions .

• Immunofluorescence (IF): Provides spatial resolution of SUPT4H1 localization within cells, often used to visualize co-localization with other transcription-related proteins like SUPT5H .

• Chromatin Immunoprecipitation (ChIP): Though not explicitly mentioned in the search results, ChIP assays using SUPT4H1 antibodies are important for studying its association with chromatin and specific DNA regions during transcriptional regulation.

Each application requires specific optimization of antibody concentration, incubation conditions, and detection methods to achieve reliable results .

How can SUPT4H1 antibodies be optimized for detection in complex samples?

Optimizing SUPT4H1 antibody protocols for complex samples requires systematic approach to ensure specific detection while minimizing background:

For Western blot applications, researchers should first determine the optimal antibody concentration through titration experiments (typically starting with dilutions between 1:500 and 1:2000) . Blocking conditions are critical - using 3% nonfat dry milk in TBST has shown effectiveness in reducing non-specific binding . When detecting SUPT4H1 in tissue lysates or complex cellular extracts, loading approximately 25μg protein per lane provides adequate signal while maintaining specificity .

For immunoprecipitation of SUPT4H1-associated complexes, consider crosslinking experiments to capture transient interactions with other transcription factors. This is particularly important when studying SUPT4H1's role within the DSIF complex alongside SUPT5H. When working with chromatin fractions, additional optimization steps such as sonication parameters and chromatin shearing efficiency should be carefully controlled.

For immunofluorescence applications, antigen retrieval methods may significantly impact detection sensitivity. Permeabilization conditions should be optimized as SUPT4H1 is primarily a nuclear protein that interacts with chromatin-associated factors. A comparison of different fixation methods (paraformaldehyde versus methanol-acetone) is advisable to determine optimal epitope accessibility .

What are the considerations when using SUPT4H1 antibodies in studying Huntington's disease mechanisms?

When investigating Huntington's disease (HD) mechanisms using SUPT4H1 antibodies, several important considerations emerge from recent research:

SUPT4H1 has been identified as a potential therapeutic target in HD as it selectively supports the transcription of genes containing long trinucleotide repeats, such as the expanded CAG repeats in the huntingtin (HTT) gene . When designing experiments to study this relationship, researchers should consider using SUPT4H1 antibodies alongside HTT antibodies that specifically recognize either wild-type or mutant forms to establish correlation between SUPT4H1 levels and HTT expression.

In gene editing experiments targeting SUPT4H1, antibody validation becomes particularly critical. Recent studies demonstrated that SUPT4H1 editing in HD-induced pluripotent stem cell-derived neural precursor cells (iPSC-NPCs) reduced mutant HTT expression without affecting wild-type HTT expression . When evaluating such selective effects, researchers must ensure their antibodies can reliably distinguish between subtle changes in protein levels and provide consistent results across different experimental conditions.

For transplantation studies using SUPT4H1-edited cells, immunohistochemical analysis with validated antibodies is essential for tracking mutant HTT expression, evaluating neuronal differentiation, and monitoring reactive astrocyte formation . This requires antibodies with high specificity and sensitivity in fixed tissue preparations from animal models.

Additionally, understanding the relationship between SUPT4H1 and different HTT isoforms requires antibodies capable of recognizing specific epitopes that might be differentially exposed in various protein conformations or aggregation states .

How to interpret contradictory results from different SUPT4H1 antibody-based experiments?

When faced with contradictory results from different SUPT4H1 antibody-based experiments, researchers should systematically evaluate several key factors:

First, examine the epitope specificity of each antibody. Different antibodies targeting distinct regions of SUPT4H1 (N-terminal, middle region, or C-terminal) may yield varying results depending on protein conformation, post-translational modifications, or protein-protein interactions that could mask certain epitopes . For instance, antibodies recognizing amino acids 18-117 versus those targeting amino acids 57-106 may produce different results if the protein undergoes conformational changes during specific cellular processes .

Second, consider the expression of alternatively spliced transcript variants of SUPT4H1, which have been reported . Different antibodies may have varying affinities for these isoforms, potentially explaining discrepancies in experimental outcomes. Researchers should determine which isoforms are relevant to their specific research question and select antibodies accordingly.

Third, evaluate the specificity of each antibody through appropriate validation experiments. This includes using positive and negative controls, such as SUPT4H1 knockout/knockdown samples, recombinant proteins, or competing peptides. Western blot analysis showing the expected molecular weight band (approximately 13-14 kDa) helps confirm antibody specificity .

Fourth, assess the technical variables across experiments, including protein extraction methods, buffer compositions, and detection systems. For instance, different lysis buffers may expose epitopes differently, while various detection methods (ECL versus fluorescence-based) offer different sensitivity levels .

What controls should be incorporated when validating SUPT4H1 antibodies for specific applications?

Comprehensive validation of SUPT4H1 antibodies requires multiple control experiments to ensure specificity, sensitivity, and reproducibility:

Positive Controls: Include recombinant SUPT4H1 protein or lysates from cells known to express SUPT4H1 at detectable levels. Recombinant fusion proteins containing specific amino acid sequences of SUPT4H1 (such as those used for immunization) serve as valuable positive controls, particularly for epitope mapping . For instance, using a recombinant fusion protein containing amino acids 1-117 of human SUPT4H1 (NP_003159.1) provides a defined standard for antibody reactivity .

Negative Controls: Implement SUPT4H1 knockout or knockdown samples through CRISPR-Cas9 editing or RNA interference. The absence or significant reduction of signal in these samples provides strong evidence for antibody specificity. Additionally, control immunoglobulins matched to the host species and antibody isotype should be used at equivalent concentrations to identify non-specific binding .

Cross-reactivity Controls: Test antibody performance across multiple species if cross-species reactivity is claimed. For example, if an antibody is reported to recognize human, mouse, and rat SUPT4H1, validation should include samples from each species to confirm consistent detection patterns .

Blocking Peptide Controls: For peptide-derived antibodies, pre-incubation with the immunizing peptide should abolish specific signals. This competitive approach confirms epitope-specific binding rather than non-specific interactions .

Application-specific Controls:

• For Western blotting: Include molecular weight markers to confirm the expected 13-14 kDa band size for SUPT4H1 .

• For immunoprecipitation: Perform reverse IP experiments and mass spectrometry validation of pulled-down proteins.

• For immunohistochemistry/immunofluorescence: Include absorption controls and evaluate staining patterns in tissues with known SUPT4H1 expression profiles.

Reproducibility Controls: Test multiple antibody lots and validate across different experimental conditions and detection systems to ensure consistent results.

What are the optimal sample preparation methods for detecting SUPT4H1 in different cellular compartments?

Optimal detection of SUPT4H1 across cellular compartments requires specific sample preparation strategies that preserve protein integrity while maximizing epitope accessibility:

Nuclear Extraction: Since SUPT4H1 functions primarily in the nucleus as part of the DSIF complex , nuclear extraction protocols should be optimized for efficient isolation of nuclear proteins. A two-step fractionation approach separating cytoplasmic and nuclear fractions is recommended. Buffer compositions typically include 10-20 mM HEPES (pH 7.9), 1.5 mM MgCl₂, 0.2 mM EDTA, 0.5 mM DTT, 25% glycerol, and protease inhibitors for nuclear extraction .

Preservation of Protein-Protein Interactions: When studying SUPT4H1's interaction with SUPT5H in the DSIF complex, mild detergent conditions (0.1% NP-40 or 0.5% Triton X-100) should be used to preserve protein-protein interactions. Crosslinking with formaldehyde prior to extraction may stabilize transient interactions .

Chromatin-Associated Fraction: For analyzing SUPT4H1 bound to chromatin during transcription, sequential extraction protocols are recommended. After standard nuclear extraction, treatment with nucleases (DNase I or micrococcal nuclease) releases chromatin-bound proteins, allowing for specific analysis of the transcriptionally active SUPT4H1 fraction.

Fixation for Microscopy: For immunofluorescence applications, 4% paraformaldehyde fixation for 15-20 minutes at room temperature generally preserves SUPT4H1 epitopes while maintaining nuclear architecture. Permeabilization with 0.2-0.5% Triton X-100 provides antibody access to nuclear proteins .

Tissue Samples: For immunohistochemistry in formalin-fixed paraffin-embedded tissues, heat-induced epitope retrieval using citrate buffer (pH 6.0) or EDTA buffer (pH 9.0) improves detection of SUPT4H1. Testing both retrieval methods is recommended to determine optimal conditions for specific antibodies .

How can SUPT4H1 antibodies be used to investigate its role in transcriptional elongation?

SUPT4H1 antibodies can be strategically employed in multiple experimental approaches to elucidate its function in transcriptional elongation mechanisms:

Chromatin Immunoprecipitation followed by Sequencing (ChIP-seq): SUPT4H1 antibodies can be used to immunoprecipitate chromatin regions bound by the DSIF complex, followed by next-generation sequencing to identify genome-wide binding sites. This approach reveals where SUPT4H1 is actively engaged in transcriptional regulation, particularly at promoter-proximal pause sites where the DSIF complex enhances transcriptional pausing . Careful optimization of crosslinking conditions, sonication parameters, and antibody concentrations is essential for successful ChIP experiments.

Proximity Ligation Assays (PLA): Using SUPT4H1 antibodies in combination with antibodies against other transcription factors (such as SUPT5H, RNA Polymerase II, or components of the NELF complex) allows visualization of protein-protein interactions in situ. This technique is particularly valuable for studying dynamic changes in SUPT4H1 interactions during transcriptional regulation .

Immunoprecipitation coupled with Mass Spectrometry (IP-MS): SUPT4H1 antibodies can be used to pull down protein complexes for subsequent mass spectrometry analysis, revealing both known and novel interaction partners. This approach has identified SUPT4H1's association with the DSIF complex and other transcriptional regulators .

ChIP-qPCR at Model Gene Loci: Targeted ChIP experiments using SUPT4H1 antibodies at specific gene loci (such as heat shock genes or highly inducible genes) can reveal dynamic recruitment patterns during transcriptional activation or repression. This approach is particularly useful for studying the kinetics of SUPT4H1 recruitment during the transition from paused to productive elongation.

Global Run-On Sequencing (GRO-seq) combined with SUPT4H1 Depletion: While not directly using antibodies, this approach can be complemented with Western blot validation using SUPT4H1 antibodies to confirm knockdown efficiency. GRO-seq following SUPT4H1 depletion reveals genes specifically regulated by SUPT4H1-dependent transcriptional mechanisms .

Chromatin Fractionation Analysis: SUPT4H1 antibodies can be used in Western blot analysis of different chromatin fractions to determine how treatments, genetic manipulations, or cellular stresses affect SUPT4H1 recruitment to chromatin.

What are the key considerations when using SUPT4H1 antibodies for neurodegenerative disease research?

When applying SUPT4H1 antibodies in neurodegenerative disease research, particularly Huntington's disease (HD), researchers should address several critical considerations:

Selective HTT Regulation: SUPT4H1 selectively supports the transcription of genes containing long trinucleotide repeats, including the expanded CAG repeats in mutant huntingtin (HTT). Researchers should design experiments that can distinguish between SUPT4H1's effects on mutant versus wild-type HTT expression. This requires antibodies capable of detecting subtle changes in protein levels with high specificity .

Cellular Context Specificity: The effects of SUPT4H1 modulation may vary across different neural cell types. When studying SUPT4H1 in neurodegenerative contexts, researchers should evaluate its expression and function in neurons, astrocytes, and other relevant cell types using appropriate antibodies validated for neural tissues . Recent studies have shown that SUPT4H1 editing affects neuronal and reactive astrocyte differentiation differently in HD iPSC-NPCs .

Model System Considerations: When transitioning between in vitro and in vivo models (such as from HD iPSC-derived neural cells to YAC128 HD transgenic mice), antibody performance may vary. Validation in each model system is essential to ensure consistent detection of SUPT4H1 and related proteins .

Monitoring Therapeutic Interventions: For studies evaluating SUPT4H1 as a therapeutic target, antibodies must be sensitive enough to detect changes resulting from gene editing or pharmacological interventions. This is particularly important for transplantation studies using SUPT4H1-edited cells, where immunohistochemical analysis with reliable antibodies is crucial for tracking intervention outcomes .

Post-Translational Modifications: In neurodegenerative conditions, proteins often undergo altered post-translational modifications. Researchers should consider whether their SUPT4H1 antibodies recognize specific modified forms of the protein that might be particularly relevant in disease states.

Cross-Species Applications: For translational research spanning multiple model organisms, antibodies with confirmed cross-reactivity across species (human, mouse, rat) are valuable for maintaining consistent detection methodologies throughout the research pipeline .

How to effectively use SUPT4H1 antibodies in co-immunoprecipitation experiments?

Effective co-immunoprecipitation (co-IP) experiments using SUPT4H1 antibodies require careful optimization to preserve protein complexes while ensuring specific pulldown:

Buffer Optimization: For capturing SUPT4H1 interactions, particularly with its partner SUPT5H in the DSIF complex, use gentle lysis buffers containing 20-50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 1-2 mM EDTA, and mild detergents (0.1-0.5% NP-40 or Triton X-100). Avoid harsh detergents like SDS that disrupt protein-protein interactions. Include protease inhibitors to prevent degradation and phosphatase inhibitors if studying phosphorylation-dependent interactions .

Antibody Selection: Choose antibodies raised against epitopes that are unlikely to be involved in protein-protein interactions. For SUPT4H1, antibodies targeting amino acids 18-117 or 1-117 may be suitable, but researchers should verify that the epitope region doesn't overlap with known interaction domains . Consider using multiple antibodies recognizing different epitopes to confirm results.

Pre-clearing Strategy: Pre-clear lysates with appropriate control beads and non-immune IgG matching the host species of the SUPT4H1 antibody to reduce non-specific binding. This step is particularly important when working with nuclear extracts, which tend to have higher background .

Cross-linking Considerations: For capturing transient or weak interactions, consider using membrane-permeable crosslinkers like DSP (dithiobis[succinimidyl propionate]) or formaldehyde before lysis. This approach can stabilize the DSIF complex and other SUPT4H1-containing complexes that might dissociate during standard co-IP procedures.

Reciprocal Co-IP Validation: Confirm interactions by performing reciprocal co-IPs using antibodies against predicted interaction partners (such as SUPT5H or components of the RNA polymerase II complex) and detecting SUPT4H1 in the immunoprecipitates .

Elution Strategies: For subsequent functional studies or mass spectrometry analysis, consider using peptide competition elution with the immunizing peptide (if available) rather than boiling in SDS sample buffer, as this can provide cleaner samples with less antibody contamination.

Controls: Include appropriate negative controls (IgG matching the SUPT4H1 antibody's host species) and positive controls (lysates from cells known to express both SUPT4H1 and its interaction partners) . For studies of the DSIF complex, co-IP of SUPT5H serves as an important positive control .

How to address common issues with SUPT4H1 antibody specificity and sensitivity?

Addressing specificity and sensitivity challenges with SUPT4H1 antibodies requires systematic troubleshooting approaches:

Multiple Band Detection: If Western blots show multiple bands beyond the expected 13-14 kDa size of SUPT4H1 , consider several potential causes and solutions:

• Verify sample preparation methods, ensuring complete protein denaturation with sufficient SDS and reducing agents.

• Implement gradient gels (10-20%) to improve separation of low molecular weight proteins.

• Test different antibody concentrations, as excessive antibody can increase non-specific binding. Start with dilutions between 1:500-1:2000 and optimize from there .

• Consider the presence of alternatively spliced SUPT4H1 variants, which have been reported . Compare observed band patterns with predicted molecular weights of known splice variants.

• Perform peptide competition assays using the immunizing peptide to identify which bands represent specific binding.

Low Signal Intensity: When signal detection is challenging despite confirmed SUPT4H1 expression:

• Increase protein loading (25-50 μg per lane) while maintaining clean sample preparation .

• Optimize antibody incubation conditions, including extended incubation times (overnight at 4°C) and buffer composition.

• Enhance detection sensitivity by using amplification systems such as biotin-streptavidin or tyramide signal amplification for immunohistochemistry applications.

• For low-abundance samples, consider enrichment strategies such as immunoprecipitation before Western blotting.

Cross-Reactivity Issues: When evaluating antibodies across multiple species:

• Align SUPT4H1 protein sequences across target species to identify conserved regions and epitope preservation.

• Validate each antibody individually in samples from each species using appropriate positive and negative controls.

• For antibodies with claimed multi-species reactivity , empirical validation in each species is essential rather than relying solely on manufacturer claims.

Batch-to-Batch Variability: To address inconsistency between antibody lots:

• Maintain reference samples from successful experiments to benchmark new antibody batches.

• Request detailed quality control data from manufacturers, including Western blot images showing antibody performance.

• Consider creating a pooled antibody stock from multiple aliquots to minimize the impact of single-batch variations.

What methods can be used to quantify SUPT4H1 expression levels with high precision?

Accurate quantification of SUPT4H1 expression levels requires rigorous methodological approaches that maximize precision and reliability:

Quantitative Western Blot Analysis: For precise protein-level quantification, implement standardized protocols including:

• Internal loading controls appropriate for nuclear proteins (such as Lamin B1 or TATA-binding protein) rather than traditional housekeeping proteins like GAPDH or β-actin.

• Standard curves using recombinant SUPT4H1 protein at known concentrations to establish a quantitative relationship between signal intensity and protein amount.

• Digital image acquisition with unsaturated signals and analysis using software that provides linear quantification across the dynamic range.

• Technical replicates (minimum 3) and biological replicates (minimum 3) to account for both technical and biological variation .

Enzyme-Linked Immunosorbent Assay (ELISA):

• Sandwich ELISA using a capture antibody recognizing one SUPT4H1 epitope and a detection antibody recognizing a different epitope provides higher specificity than direct ELISA methods.

• For absolute quantification, generate standard curves using recombinant SUPT4H1 protein with verified concentration.

• Optimize antibody concentrations, incubation times, and blocking conditions to maximize signal-to-noise ratio .

Mass Spectrometry-Based Quantification:

• Selected Reaction Monitoring (SRM) or Parallel Reaction Monitoring (PRM) targeting specific SUPT4H1 peptides enables absolute quantification when coupled with isotope-labeled internal standards.

• This approach provides high specificity and can distinguish between different SUPT4H1 isoforms based on unique peptide sequences.

Quantitative Immunofluorescence:

• For single-cell quantification, implement automated image analysis workflows measuring nuclear SUPT4H1 intensity across multiple cells.

• Include fluorescence intensity calibration standards in each experiment to normalize between imaging sessions.

• Co-staining with markers of specific cell types or subcellular compartments enables context-specific quantification .

Digital PCR:

• While measuring mRNA rather than protein, digital PCR provides absolute quantification of SUPT4H1 transcript levels that can complement protein-level measurements.

• Design assays targeting different exon junctions to quantify specific splice variants.

Technical Considerations for All Methods:

• Implement rigorous statistical analysis, including tests for normality, appropriate statistical tests, and correction for multiple comparisons.

• Evaluate assay precision by calculating coefficients of variation (CV) across technical replicates (target CV < 10%).

• Establish limits of detection and quantification for each method through systematic dilution series.

How might SUPT4H1 antibodies contribute to understanding emerging roles of this protein in disease mechanisms?

SUPT4H1 antibodies will be instrumental in exploring several emerging areas of research that connect this transcription elongation factor to disease mechanisms:

Expanded Trinucleotide Repeat Disorders: Building on the established role of SUPT4H1 in Huntington's disease , researchers can use validated antibodies to investigate similar mechanisms in other trinucleotide repeat disorders such as myotonic dystrophy, fragile X syndrome, and various spinocerebellar ataxias. By comparing SUPT4H1 binding patterns across these disorders, common mechanisms of pathogenic repeat expansion transcription might be identified. Immunoprecipitation followed by RNA sequencing could reveal how SUPT4H1 differentially regulates the expression of various repeat-containing transcripts.

Cancer Biology: SUPT4H1 antibodies will be valuable for investigating dysregulated transcription elongation in cancer. Immunohistochemical analysis of tumor tissue microarrays using specific SUPT4H1 antibodies could identify expression patterns correlating with tumor progression, metastasis, or therapeutic response. Combining SUPT4H1 ChIP-seq with RNA-seq in matched normal-tumor samples could identify cancer-specific transcriptional programs regulated by this factor.

Viral Pathogenesis: Given SUPT4H1's known role in HIV-1 transcription , antibodies targeting this protein will help elucidate similar mechanisms in other viral infections. Researchers can use SUPT4H1 antibodies to study how various viruses manipulate transcriptional elongation machinery to optimize viral gene expression. Immunofluorescence co-localization studies could reveal dynamic redistribution of SUPT4H1 during viral infection cycles.

Stress Response Mechanisms: SUPT4H1 antibodies can be applied to investigate its potential role in cellular stress responses, particularly those involving rapid transcriptional reprogramming. ChIP-seq experiments using SUPT4H1 antibodies before and after various stressors (oxidative stress, heat shock, DNA damage) could reveal stress-specific recruitment patterns and transcriptional control mechanisms.

Therapeutic Target Validation: As SUPT4H1 editing has shown promise in reducing mutant HTT expression , antibodies will be essential for validating and optimizing such therapeutic approaches. Researchers can use SUPT4H1 antibodies to monitor protein levels following various intervention strategies, correlating SUPT4H1 reduction with therapeutic outcomes in preclinical models.

What experimental design considerations are crucial when using SUPT4H1 antibodies in gene editing studies?

When incorporating SUPT4H1 antibodies into gene editing research, several critical experimental design considerations must be addressed:

Validation of Editing Efficiency: SUPT4H1 antibodies are essential for confirming protein-level changes following gene editing. Western blot analysis should be performed to quantify the degree of protein reduction, using standardized loading amounts (typically 25-50 μg total protein) and optimized antibody dilutions (1:500-1:2000) . Complete knockout versus partial knockdown should be clearly distinguished through careful quantification.

Establishing Temporal Dynamics: After gene editing, researchers should use SUPT4H1 antibodies to track protein levels over time, establishing the kinetics of protein depletion and potential compensation by related factors. This longitudinal analysis is particularly important for therapeutic applications, as seen in studies of SUPT4H1-edited HD iPSC-NPCs .

Spatial Resolution of Effects: Immunofluorescence using validated SUPT4H1 antibodies provides critical information about cell-type specific effects of gene editing, especially in heterogeneous cultures or tissues. This approach revealed differential effects on neuronal versus astrocytic differentiation in HD models following SUPT4H1 editing .

Monitoring Off-Target Effects: When targeting SUPT4H1, researchers should use antibodies against potential off-target proteins identified through computational prediction. Additionally, antibodies against SUPT5H should be used to monitor potential compensatory changes in the partner protein of the DSIF complex .

Clonal Variation Analysis: For studies using CRISPR-edited cell lines, researchers should analyze multiple independent clones using SUPT4H1 antibodies to confirm consistent protein reduction across clones, distinguishing gene-specific effects from clonal artifacts.

Dosage-Dependent Effects: Creating and analyzing partial knockdown versus complete knockout models helps establish dose-dependent relationships between SUPT4H1 levels and phenotypic outcomes. This requires antibodies capable of reliable quantification across a wide dynamic range of protein expression.