FunctionCore component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling.
Sequence similaritiesBelongs to the histone H4 family.
Post-translational modificationsAcetylation at Lys-6 (H4K5ac), Lys-9 (H4K8ac), Lys-13 (H4K12ac) and Lys-17 (H4K16ac) occurs in coding regions of the genome but not in heterochromatin. Citrullination at Arg-4 (H4R3ci) by PADI4 impairs methylation. Monomethylation and asymmetric dimethylation at Arg-4 (H4R3me1 and H4R3me2a, respectively) by PRMT1 favors acetylation at Lys-9 (H4K8ac) and Lys-13 (H4K12ac). Demethylation is performed by JMJD6. Symmetric dimethylation on Arg-4 (H4R3me2s) by the PRDM1/PRMT5 complex may play a crucial role in the germ-cell lineage. Monomethylated, dimethylated or trimethylated at Lys-21 (H4K20me1, H4K20me2, H4K20me3). Monomethylation is performed by SET8. Trimethylation is performed by SUV420H1 and SUV420H2 and induces gene silencing. Ubiquitinated by the CUL4-DDB-RBX1 complex in response to ultraviolet irradiation. This may weaken the interaction between histones and DNA and facilitate DNA accessibility to repair proteins. Monoubiquitinated at Lys-92 of histone H4 (H4K91ub1) in response to DNA damage. The exact role of H4K91ub1 in DNA damage response is still unclear but it may function as a licensing signal for additional histone H4 post-translational modifications such as H4 Lys-21 methylation (H4K20me). Sumoylated, which is associated with transcriptional repression.
Immunocytochemistry/ Immunofluorescence - Anti-Histone H4 (acetyl K91) antibody - ChIP Grade (ab4627)This image is courtesy of an anonymous Abreview
ab4627 staining Histone H4 (acetyl K91) in mouse C2C12 muscle fibroblast cultured cells by ICC/IF (Immunocytochemistry/immunofluorescence). Cells were fixed with paraformaldehyde, permeabilized with 0.1% Triton X-100 and blocked with 5% serum for 20 minutes at 23°C. Samples were incubated with primary antibody (1/1000 in 3% BSA + 0.1% Triton X-100 in PBS) for 12 hours at 4°C. ab150077, an Alexa Fluor® 488-conjugated goat anti-rabbit IgG polyclonal (1/2000) was used as the secondary antibody.
IHC image of ab4627 staining Histone H2A.X in human colon formalin fixed paraffin embedded tissue sections, performed on a Leica Bond. The section was pre-treated using heat mediated antigen retrieval with sodium citrate buffer (pH6, epitope retrieval solution 1) for 20 mins. The section was then incubated with ab4627, 1µg/ml, for 15 mins at room temperature and detected using an HRP conjugated compact polymer system. DAB was used as the chromogen. The section was then counterstained with haematoxylin and mounted with DPX. No primary antibody was used in the negative control (shown on the inset).
For other IHC staining systems (automated and non-automated) customers should optimize variable parameters such as antigen retrieval conditions, primary antibody concentration and antibody incubation times.
Chromatin was prepared from U2OS cells according to the Abcam X-ChIP protocol. Cells were fixed with formaldehyde for 10 min. The ChIP was performed with 25 µg of chromatin, 2 µg of ab4627 (blue), and 20 µl of Protein A/G sepharose beads. No antibody was added to the beads control (yellow). The immunoprecipitated DNA was quantified by real time PCR (Taqman approach for active and inactive loci, Sybr green approach for heterochromatic loci). Primers and probes are located in the first kb of the transcribed region.
Western blot - Anti-Histone H4 (acetyl K91) antibody - ChIP Grade (ab4627)
Predicted band size : 12 kDa
Rabbit polyclonal to Histone H4 acetyl K91 (ab4627). All lanes contain 1ug of calf thymus Histone prep.
Lane 1: ab4627 at 1/500 Lane 2: ab4627 at 1/1000 Lane 3: ab4627 at 1/500 + 2ug acetyl K91 blocking peptide (ab10112) Lane 4: ab4627 at 1/1000 + 2ug acetyl K91 blocking peptide (ab10112)
Secondary antibody: Goat anti-rabbit (HRP) - ab6721 at 1/2000