Acetyl-Histone H3 (Lys79) Antibody

What is Histone H3 Lysine 79 (H3K79) acetylation and what is its biological significance?

Histone H3 Lysine 79 (H3K79) acetylation is a post-translational modification that occurs at the lysine 79 residue within the globular domain of histone H3. Unlike many other histone modifications that occur on the N-terminal tail, H3K79 is positioned within the core domain, suggesting specialized functions in chromatin regulation. This modification plays important roles in transcriptional regulation, chromatin structure modulation, and various cellular processes including stress response pathways .

The acetylation status of H3K79 can be significantly altered by histone deacetylase (HDAC) inhibitors like sodium butyrate, indicating its dynamic nature and potential role in gene expression regulation .

How does H3K79 acetylation differ from other histone H3 modifications?

H3K79 acetylation differs from other histone modifications in several key aspects:

• Genomic location: Unlike common modifications such as H3K4, H3K9, H3K14, H3K27, and H3K36 that occur on the histone tail, H3K79 is located within the globular domain of histone H3, potentially affecting nucleosome structure differently .

• Specificity: The RM156 antibody shows no cross-reactivity with other acetylated lysines in Histone H3, including K4ac, K9ac, K14ac, K18ac, K23ac, K27ac, K36ac, K56ac, or K122ac, demonstrating the distinct nature of this modification .

• Regulatory mechanisms: While tail modifications often directly affect DNA-histone interactions, H3K79 modifications may influence histone-histone interactions within nucleosomes, potentially affecting higher-order chromatin structure in unique ways .

What are the optimal conditions for using Anti-Acetyl-Histone H3 (Lys79) Antibody in Western Blot experiments?

Based on validated protocols, the optimal conditions for Western Blot detection of H3K79 acetylation are:

• Antibody concentration: 1 μg/mL of the RM156 clone has been validated for Western blotting applications .

• Sample preparation: Acid extraction of histones from cells provides the most reliable results, typically using HeLa acid extracts as demonstrated in validation studies .

• Treatment conditions: Sodium butyrate treatment of cells enhances H3K79 acetylation signals, making it useful as a positive control. Western blot analysis shows clear detection of acetyl-Histone H3 (Lys79) in sodium butyrate-treated HeLa acid extracts but minimal signal in untreated samples .

• Expected results: A single band at approximately 17 kDa corresponding to acetylated histone H3 should be detected in the treated samples .

How should samples be prepared for detecting H3K79 acetylation using ChIP?

For optimal Chromatin Immunoprecipitation (ChIP) results when studying H3K79 acetylation:

• Antibody amount: Use 5 μg of the RM156 antibody per immunoprecipitation reaction .

• Treatment conditions: Sodium butyrate treatment provides an effective positive control for increased H3K79 acetylation levels. ChIP experiments have been successfully performed using this antibody on both untreated and sodium butyrate-treated HeLa cells .

• Analysis method: Real-time PCR with primers specific to regions of interest can quantify enrichment. Validation studies have demonstrated successful ChIP with the RM156 antibody followed by qPCR analysis targeting specific gene regions .

• Controls: Include input samples (non-immunoprecipitated chromatin) and IgG controls (non-specific antibody) to establish baseline and non-specific binding levels .

What techniques are validated for Anti-Acetyl-Histone H3 (Lys79) Antibody applications?

The Anti-Acetyl-Histone H3 (Lys79) Antibody (clone RM156) has been validated for multiple techniques:

• Western Blotting: Effective at 1 μg/mL concentration for detecting H3K79ac in acid-extracted histones .

• Chromatin Immunoprecipitation (ChIP): Successfully used at 5 μg per reaction with subsequent qPCR analysis .

• Immunocytochemistry (ICC): Demonstrated effectiveness in detecting nuclear H3K79ac in sodium butyrate-treated HeLa cells, with actin filaments counterstained using fluorescein phalloidin .

• Multiplex Analysis: Suitable at concentrations of 0.05-0.2 μg/mL, allowing simultaneous detection with other targets .

• ELISA: Effective as a capture antibody at 5 μg/mL in sandwich ELISA formats, with clear differentiation between treated and untreated samples .

How does sodium butyrate treatment affect H3K79 acetylation patterns?

Sodium butyrate, a histone deacetylase (HDAC) inhibitor, has significant effects on H3K79 acetylation patterns:

• Global increases: Western blotting data shows marked increase in H3K79ac signals in sodium butyrate-treated HeLa cells compared to untreated controls, indicating that this modification is regulated by HDAC activity .

• Gene-specific enrichment: ChIP-qPCR data indicates that sodium butyrate treatment leads to differential enrichment of H3K79ac across specific genomic loci. Some genes show stronger enrichment than others, suggesting gene-specific regulation mechanisms .

• Functional significance: The differential response to HDAC inhibition suggests that H3K79 acetylation may play important roles in transcriptional activation of specific genes, particularly in response to cellular stress conditions .

What is the specificity profile of the Anti-Acetyl-Histone H3 (Lys79) Antibody?

The RM156 monoclonal antibody demonstrates exceptional specificity for H3K79 acetylation:

• Cross-reactivity testing: Validation studies have confirmed that RM156 specifically reacts to Histone H3 acetylated at Lysine 79 (K79ac) with no cross-reactivity to other acetylated lysines in Histone H3 .

• Comprehensively tested: The antibody shows no cross-reactivity with acetylated Lysine 4 (K4ac), Lysine 9 (K9ac), Lysine 14 (K14ac), Lysine 18 (K18ac), Lysine 23 (K23ac), Lysine 27 (K27ac), Lysine 36 (K36ac), Lysine 56 (K56ac), or Lysine 122 (K122) in Histone H3 .

• Target validation: The antibody was raised against a linear peptide corresponding to human Histone H3 acetylated at Lys79, ensuring targeted specificity .

This comprehensive specificity profile makes RM156 an excellent tool for studying H3K79 acetylation without interference from other histone modifications.

How do H3K79 acetylation patterns correlate with gene expression?

While direct correlations between H3K79 acetylation and gene expression are still being fully characterized, several important observations can be made:

• Sodium butyrate response: Genes showing increased H3K79ac after sodium butyrate treatment often correlate with increased transcriptional activity, though this relationship is complex and context-dependent .

• Locus-specific effects: ChIP experiments demonstrate that H3K79ac enrichment varies across different genomic loci, suggesting gene-specific regulatory roles .

• Regulatory dynamics: The response of H3K79ac to HDAC inhibitors like sodium butyrate suggests that the dynamic regulation of this modification contributes to transcriptional flexibility in response to cellular stress or environmental changes .

What are common causes of inconsistent results when using Anti-Acetyl-Histone H3 (Lys79) Antibody?

Several factors can contribute to variability in H3K79ac detection:

• Sample preparation issues:

  • Inadequate histone extraction

  • Variable fixation conditions

  • Inconsistent treatment with HDAC inhibitors like sodium butyrate

• Technical variations:

  • Using antibody concentrations different from validated protocols (1 μg/mL for WB, 5 μg for ChIP)

  • Inadequate blocking or washing steps

  • Suboptimal incubation conditions

• Biological factors:

  • Cell type-specific differences in H3K79 acetylation levels

  • Cell cycle phase variations affecting histone modification patterns

  • Stress conditions affecting global acetylation levels

To minimize these issues, researchers should carefully follow validated protocols, include appropriate controls, and maintain consistent experimental conditions across studies .

How can detection sensitivity of H3K79 acetylation be improved in samples with low abundance?

Strategies to enhance detection of low-abundance H3K79 acetylation:

• Sample enrichment:

  • Increase starting material quantity

  • Use sodium butyrate treatment (demonstrated in validation studies) to boost acetylation levels

  • Optimize histone extraction protocols for preservation of acetylated histones

• Technical optimizations:

  • For Western blotting, use high-sensitivity detection substrates

  • For ChIP, increase antibody amount beyond the standard 5 μg with larger chromatin inputs

  • For ICC, extend primary antibody incubation (overnight at 4°C)

• Alternative approaches:

  • Consider ELISA-based detection, which has been validated using RM156 at 5 μg/mL as the capture antibody

  • Multiplex with other histone marks to provide context and increase data richness

How does H3K79 acetylation compare with other histone acetylation marks?

H3K79 acetylation has several unique characteristics compared to other histone acetylation marks:

• Structural context: Unlike common acetylation sites like H3K9 and H3K14 that occur on the histone tail, H3K79 is located within the globular domain, potentially affecting nucleosome structure differently .

• Modification dynamics: H3K79ac responds to HDAC inhibitors like sodium butyrate, similar to other acetylation marks, but may have unique kinetics and threshold responses .

• Specificity of detection: The RM156 antibody shows no cross-reactivity with other acetylated lysines including K4ac, K9ac, K14ac, K18ac, K23ac, K27ac, K36ac, K56ac, or K122ac, demonstrating the distinct nature of this modification .

• Combinatorial patterns: While H3K9/K14 acetylation often occurs as a combined mark (as targeted by some antibodies like #9677), H3K79ac appears to be regulated independently .

What methodological differences should be considered when comparing studies of H3K79 acetylation?

When comparing different studies examining H3K79 acetylation, several methodological considerations are critical:

• Antibody validation: Confirm that studies used properly validated antibodies with demonstrated specificity like RM156, which has been rigorously tested against multiple potential cross-reactive sites .

• Treatment conditions: Note whether studies used HDAC inhibitors like sodium butyrate and at what concentrations and durations, as these significantly affect H3K79ac levels .

• Technical approaches: Different techniques (Western blot, ChIP, ICC, ELISA) may yield different insights about H3K79ac distribution and abundance .

• Cell types and contexts: H3K79ac patterns may vary between cell types, developmental stages, or disease states, making direct comparisons challenging without accounting for these variables.

• Data normalization: Consider how H3K79ac signals were normalized (e.g., to total H3, to other histone marks, or to input in ChIP experiments) when comparing quantitative results across studies.

What are emerging applications for Anti-Acetyl-Histone H3 (Lys79) Antibody in epigenetic research?

Several promising research directions are emerging for the study of H3K79 acetylation:

• Single-cell epigenomics: Adapting H3K79ac detection for single-cell resolution to understand cell-to-cell variability in this epigenetic mark.

• Disease-specific patterns: Investigating how H3K79ac patterns change in various disease states, potentially identifying new biomarkers or therapeutic targets.

• Therapeutic response monitoring: Using H3K79ac as a readout for responses to HDAC inhibitors and other epigenetic drugs in research and clinical settings.

• Multi-omics integration: Combining H3K79ac ChIP-seq data with transcriptomics, proteomics, and other epigenomic datasets to build comprehensive regulatory models .

• Novel multiplexing approaches: Further developing the validated multiplexing capabilities of antibodies like RM156 to simultaneously detect H3K79ac alongside other epigenetic marks .

What technological advances might improve H3K79 acetylation research?

Several technological developments show promise for advancing H3K79 acetylation research:

• CUT&RUN and CUT&Tag adaptations: Modifying these advanced chromatin profiling techniques for H3K79ac detection could provide higher resolution with less starting material.

• Live-cell imaging approaches: Developing techniques to visualize H3K79ac dynamics in living cells would enable temporal studies of this modification's role in chromatin regulation.

• Mass spectrometry advancements: Improved sensitivity in mass spectrometry-based approaches could allow more comprehensive quantification of H3K79ac alongside other histone modifications.

• Automated ChIP platforms: Standardization of ChIP procedures using automated platforms could improve reproducibility of H3K79ac detection across laboratories.

• CRISPR-based epigenetic editing: Targeted modulation of H3K79 acetylation using CRISPR-based writers and erasers could help establish causative roles in gene regulation .