H3K9me3 and H4K20me3 represent the epigenetic landscape for 53BP1 binding to DNA lesions

Abstract

Methylation of histones H4 at lysine 20 position (H4K20me), which is functional in DNA repair, represents a binding site for the 53BP1 protein. Here, we show a radiation-induced increase in the level of H4K20me3 while the levels of H4K20me1 and H4K20me2 remained intact. H4K20me3 was significantly pronounced at DNA lesions in only the G1 phase of the cycle, while this histone mark was reduced in very late S and G2 phases when PCNA was recruited to locally micro-irradiated chromatin. H4K20me3 was diminished in locally irradiated Suv39h1/h2 double knockout (dn) fibroblasts, and the same phenomenon was observed for H3K9me3 and its binding partner, the HP1β protein. Immunoprecipitation showed the existence of an interaction between H3K9me3-53BP1 and H4K20me3-53BP1; however, HP1β did not interact with 53BP1. Together, H3K9me3 and H4K20me3 represent epigenetic markers that are important for the function of the 53BP1 protein in non-homologous end joining (NHEJ) repair. The very late S phase represents the cell cycle breakpoint when a DDR function of the H4K20me3-53BP1 complex is abrogated due to recruitment of the PCNA protein and other DNA repair factors of homologous recombination to DNA lesions.

N6-Adenosine Methylation in RNA and a Reduced m3G/TMG Level in Non-Coding RNAs Appear at Microirradiation-Induced DNA Lesions

“…Immunofluorescence was performed following [47]. The cells were fixed in 4% paraformaldehyde (PFA) for 10 min at room temperature (RT), permeabilized with 0.2% Triton X-100 (Merck) for 15 min (Merck), and washed twice in phosphate-buffered saline (PBS) for 10 min.…”

“…Western blotting was performed using the methods reported by [47]. We used the following primary antibodies: anti-phosphorylated histone H2AX (γH2AX; phospho S139; #ab2893, Abcam), anti-FTO (#ab92821, Abcam), anti-α-tubulin (#ab80779 Abcam), anti-DNMT1 (#ab188453 Abcam), anti-H3 (#ab7091, Abcam), anti-H3K9me3 (#ab8898, Abcam), anti-METTL3 (#A8370, Abclonal), anti-METTL14 (#A8530, Abclonal), and anti-METTL16 (#HPA020352, Atlas Antibodies).…”

“…Microirradiation was performed by both lasers (355-nm and 405-nm of the wavelength). The lasers were connected to a Leica SP5 X confocal microscope (see description in [47]). In the case of the SP8 confocal system, we used a 405-nm laser line.…”

Histone Tail Analysis Reveals H3K36me2 And H4K16ac As Epigenetic Signatures of Diffuse Intrinsic Pontine Glioma

“…Since monomethylation of H3K27, H3K79, and H4K20 are all linked to gene activation, whereas tri-methylation of H3K27 and H3K79 are linked to repression [54], these ndings may provide additional insight into the mechanism by which BRDi alters tumorigenic gene expression in DIPG. H4K20me, which is functional in DNA repair, represents a binding site for the 53BP1 protein; H3K9me3 and H4K20me3 represent epigenetic markers important to the function of 53BP1 in non-homologous end joining (NHEJ) repair [55]. As such, additional studies of how JQ1 may augment response to RT are necessary.…”

Histone tail analysis reveals H3K36me2 and H4K16ac as epigenetic signatures of diffuse intrinsic pontine glioma

“…Since monomethylation of H3K27, H3K79, and H4K20 are all linked to gene activation, whereas tri-methylation of H3K27 and H3K79 are linked to repression [54], these ndings may provide additional insight into the mechanism by which BRDi alters tumorigenic gene expression in DIPG. H4K20me, which is functional in DNA repair, represents a binding site for the 53BP1 protein; H3K9me3 and H4K20me3 represent epigenetic markers important to the function of 53BP1 in non-homologous end joining (NHEJ) repair [55].…”