Histone H2A.XS139ph antibody (pAb)

RRID: AB_2793161
Aliases: gammaH2AX, gH2AX, gH2A.X
Catalog No: 39117 Format: 100 µg $480 Buy
Catalog No: 39118 Format: 10 µg $120 Buy

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Antibody Type:
Protein A Chromatography
Molecular Weight:
15 kDa
Human, Wide Range Predicted


ChIP Validated ChIP-Seq Validated Western Blot Validated Immunofluorescence Validated Immunocytochemistry Validated

Application Notes

Applications Validated by Active Motif:
ICC/IF: 1:500 dilution
WB*: 1:1,000 - 1:5,000 dilution

*Note: many chromatin-bound proteins are not soluble in a low salt nuclear extract and fractionate to the pellet. Therefore, we recommend a High Salt / Sonication Protocol when preparing nuclear extracts for Western Blot.

Published Applications

The following applications have been published using this antibody. Unless noted above, Active Motif may not have validated the antibody for use in these applications:


View publications that use Active Motif products & services here. Enter the product number(s) to see publications & applications that use this antibody.


This Histone H2AX phospho Ser139 antibody was raised against a peptide including phospho-serine 139 of histone H2AX.


10 mM sodium phosphate pH 7.5, 150 mM NaCl, 30% glycerol, 0.035% sodium azide.

View our Guide to Histone Modifications and Biological Function.


Histone H2A.XS139ph antibody (pAb) - 100 µg (Cat. No. 39117)



Histone H2AX phospho Ser139 antibody tested by immunofluorescence.
HeLa cells stained with Histone H2AX phospho Ser139 antibody (1:500 dilution) using MAX Stain™ Immunofluorescence Tools. The HeLa cells were blocked with MAXblock™ Blocking Medium and stained with Histone H2AX phospho Ser139 antibody.
Panel A: Untreated HeLa cells.
Panel B: Cells fixed and stained 90 minutes after 3 Gy ionizing radiation treatment.
Top images: Cells were stained with DAPI.
Middle images: Same cells stained with Histone H2AX phospho Ser139 antibody.
Bottom images: Merge of both images above.
Images were made using Zeiss Axiovision with equivalent acquisition settings for direct comparison. Note Panel B-middle image, which shows intense nuclear clustering of ionizing radiation-induced phosphorylation of Ser139 of H2AX. In contrast, Panel A-middle image shows no detectable phosphorylated H2AX.

Histone H2AX phospho Ser139 antibody tested by immunofluorescence.
ETO-treated HeLa cells stained with Cat. No. 39117 (1:500 dilution, red) and counterstained with DAPI (blue).

Histone H2AX phospho Ser139 antibody tested by Western blot.
Western blot: Nuclear extract of U2OS cells (20 µg per lane) probed with Histone H2AX phospho Ser139 polyclonal antibody (1:500 dilution).

Lane 1: untreated cells
Lane 2: cells treated with camptothecin


Histone H2AX phospho Ser139 (H2AX, H2A histone family member X) replaces conventional H2A in a subset of nucleosomes. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries that require DNA as a template. Histones thereby play a central role in transcriptional regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called the histone code, and nucleosome remodeling. Histone H2AX is required for checkpoint-mediated arrest of cell cycle progression in response to low doses of ionizing radiation, and for efficient repair of DNA double-strand breaks (DSBs), specifically when modified by C-terminal phosphorylation.

Positive Control

Active Motif's HeLa nuclear extract (Catalog No. 36010) can be used as a positive control for Histone H2AX phospho Ser139 antibody.

Chromatin IP Assays

This antibody has been validated for use in ChIP and/or ChIP-Seq, and can be used with Active Motif's ChIP-IT® High Sensitivity Kit or our magnetic bead-based ChIP-IT® Express Kits. For an overview of all of our ChIP products, please visit our Chromatin IP Page to learn about ChIP products designed for use with Histone H2A.XS139ph antibody (pAb).


Some products may be shipped at room temperature. This will not affect their stability or performance. Avoid repeated freeze/thaw cycles by aliquoting items into single-use fractions for storage at -20°C for up to 2 years. Keep all reagents on ice when not in storage.


This product is guaranteed for 12 months from date of receipt.

This product is for research use only and is not for use in diagnostic procedures.

Application Key

  • ChIP = Chromatin Immunoprecipitation;
  • ChIP = ChIP Sequencing;
  • CUT&RUN = Cleavage Under Targets and Release Using Nuclease;
  • CUT&Tag = Cleavage Under Targets and Tagmentation;
  • DB = Dot Blot;
  • ELISA = Enzyme-linked Immunosorbent Assay;
  • EMSA = Electrophoretic Mobility Shift Assay
  • FC = Flow Cytometry;
  • ICC = Immunocytochemistry;
  • IF = Immunofluorescence;
  • IHC = Immunohistochemistry;
  • IP = Immunoprecipitation;
  • MeDIP = Methyl-DNA Immunoprecipitation;
  • NEU = Neutralizing;
  • WB = Western Blotting