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DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells [ChIP-Seq]

ABSTRACT: DNA double-strand break (DSB) repair by homologous recombination is confined to the S and G2 phases of the cell cycle partly due to 53BP1 antagonizing DNA end resection in G1 phase and non-cycling quiescent (G0) cells where DSBs must be repaired by non-homologous end joining (NHEJ). Unexpectedly, we uncovered extensive MRE11- and CtIP-dependent DNA end resection at DSBs in G0 mammalian cells. A whole genome CRISPR/Cas9 screen revealed the DNA-dependent kinase (DNA-PK) complex as a key factor in promoting DNA end resection in G0 cells. In agreement, depletion of FBXL12, which promotes ubiquitylation and removal of the KU70/KU80 subunits of DNA-PK from DSBs, promotes even more extensive resection in G0 cells. In contrast, a requirement for DNA-PK in promoting DNA end resection in cycling cells at the G1 or G2 phase cells was not observed. Our findings establish that DNA-PK uniquely promotes DNA end resection in G0, but not in G1 or G2 phase cells, and has important implications for DNA DSB repair in quiescent cells.

ORGANISM(S): Mus musculus

PROVIDER: GSE186086 | GEO | 2022/05/16

REPOSITORIES: GEO

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DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells [END-seq]

Project description:DNA double-strand break (DSB) repair by homologous recombination is confined to the S and G2 phases of the cell cycle partly due to 53BP1 antagonizing DNA end resection in G1 phase and non-cycling quiescent (G0) cells where DSBs must be repaired by non-homologous end joining (NHEJ). Unexpectedly, we uncovered extensive MRE11- and CtIP-dependent DNA end resection at DSBs in G0 mammalian cells. A whole genome CRISPR/Cas9 screen revealed the DNA-dependent kinase (DNA-PK) complex as a key factor in promoting DNA end resection in G0 cells. In agreement, depletion of FBXL12, which promotes ubiquitylation and removal of the KU70/KU80 subunits of DNA-PK from DSBs, promotes even more extensive resection in G0 cells. In contrast, a requirement for DNA-PK in promoting DNA end resection in cycling cells at the G1 or G2 phase cells was not observed. Our findings establish that DNA-PK uniquely promotes DNA end resection in G0, but not in G1 or G2 phase cells, and has important implications for DNA DSB repair in quiescent cells.

2022-05-16 | GSE186085 | GEO

Cell cycle-dependent resolution of DNA double-strand breaks repair

Project description:Damage to genomic DNA, especially as DNA double strand breaks (DSB), elicits prompt activation of DNA damage response (DDR) which arrest cell-cycle either G1/S or G2/M to avoid entering S and M phase with DNA damage. In mammalian organs cells are in both proliferating and quiescent states. Quiescent cells are already arrested in G0, therefore there may be fundamental difference in DDR between proliferating and quiescent cells. To address these differences we studied recruitment of DSB repair factors and resolution of DNA lesions induced at site-specific DSBs occurring at different cell cycle phases, i.e. in asynchronously proliferating, G0, and G1 arrested cells. Strikingly, DSBs occurring in G0 quiescent cells are irreparable with a sustained activation of p53-pathway. Conversely, reentry of G0-damaged cells into cell cycle progression, show a delayed clearance of recruited DNA repair factors bound at DSBs, indicating an inefficient repair when compared to DSBs induced in asynchronously proliferating or G1 cells. Moreover, we found that initial recognition of DSBs and assembly of DSB factors is largely similar at different cell cycle phases. Our study thereby demonstrates the crucial role of cell cycle phases in repair and resolution of DSBs.

2015-12-30 | GSE71447 | GEO

Ubiquitin ligase WWP2 targets RNA polymerase II in a DNA-PK-dependent transcription shutoff circuitry for DNA repair

Project description:DNA double-strand breaks (DSBs) at RNA polymerase II (RNAPII)-transcribed genes lead to inhibition of transcription. DNA protein kinase (DNA-PK) complex plays a pivotal role in transcription inhibition at DSBs by stimulating proteasome-dependent eviction of RNAPII at these lesions. How DNA-PK triggers RNAPII eviction to inhibit transcription at DSBs remained unclear. Here we show that the HECT E3 ubiquitin ligase WWP2 associates with components of the DNA-PK and RNAPII complexes and is recruited to DSBs at RNAPII-transcribed genes. In response to DSBs, WWP2 targets the RNAPII subunit RPB1 for K48-linked ubiquitylation, thereby driving DNA-PK- and proteasome-dependent eviction of RNAPII. The lack of WWP2 or expression of non-ubiquitylatable RPB1 abrogates the loading of Non-Homologous End-Joining (NHEJ) factors, including DNA-PK and XRCC4/DNA ligase IV, and impairs DSB repair. These findings suggest that WWP2 operates in a DNA-PK-dependent shut-off circuitry for RNAPII clearance that promotes DSB repair by protecting the NHEJ machinery from collision with the transcription machinery.

2019-03-29 | PXD012606 | Pride

Dbf4-dependent kinase promotes cell-cycle controlled resection of DNA double strand breaks and repair by homologous recombination

Project description:DNA double-strand breaks (DSBs) can be repaired by several pathways. In eukaryotes, repair pathway choice – the cellular decision making underlying DSB repair – occurs at the level of DSB resection and is controlled by the cell cycle. Upon cell cycle-dependent activation, cyclin-dependent kinases (CDKs) phosphorylate resection proteins and thereby stimulate DSB resection and repair by homologous recombination (HR). Here, we identify Dbf4-dependent kinase (DDK) as a second major cell cycle regulator of DNA end resection. Using inducible genetic and chemical inhibition of DDK in budding yeast and human cells, we show that DNA resection and HR require activation by DDK. Mechanistically, DDK catalyzes phosphorylation of at least two resection nucleases. Via phosphorylation of the Mre11 activator Sae2 it promotes activation of resection initiation, via phosphorylation of the Dna2 nuclease it promotes long-range resection. Notably, synthetic activiation of DDK allows limited resection and HR in G1 cells, suggesting that DDK is a key component of DSB repair decision making.

2024-02-22 | GSE233549 | GEO

Role of 53BP1 in End Protection and DNA synthesis at DNA breaks [ChIP-seq]

Project description:Double-strand break (DSB) repair choice is greatly influenced by the initial processing of DNA ends. 53BP1 limits the formation of recombinogenic single strand DNA (ssDNA) in BRCA1-deficient cells leading to defects in homologous recombination (HR). However, the exact mechanisms by which 53BP1 inhibits DSB resection remain unclear. Previous studies have identified two potential pathways: protection against exonucleases presumably through the Shieldin (SHLD) complex binding to ssDNA, and localized DNA synthesis through the (CTC1-STN1-TEN1) CST and DNA polymerase alpha (Polα) to counteract resection. We present evidence here that 53BP1-mediated exonuclease protection plays a more significant role than CST/Polα synthesis in countering hyper-resection at DSBs in G1 phase. Using a combinatorial approach of END-seq, SAR-seq, and RPA ChIP-seq, we directly assessed the extent of resection, DNA synthesis, and ssDNA, respectively, at AsiSI-induced DSBs. We show that in the presence of 53BP1, Polα-dependent DNA synthesis reduces the fraction of resected DSBs and the resection lengths. However, in the absence of 53BP1, Polα activity is sustained on ssDNA yet does not substantially counter resection. In contrast, Exo1 nuclease activity is essential for hyperresection in the absence of 53BP1. Thus, 53BP1 inhibits resection mainly through end-protection rather than by promoting fill-in.

2021-09-10 | GSE181668 | GEO

Role of 53BP1 in End Protection and DNA synthesis at DNA breaks [SAR-seq]

2021-09-10 | GSE181667 | GEO

Role of 53BP1 in End Protection and DNA synthesis at DNA breaks [END-seq]

2021-09-10 | GSE181669 | GEO

A Rad50-null mutation in mouse germ cells causes reduced DSB formation, abnormal DSB end resection and complete loss of germ cells

Project description:Programed DNA double-strand breaks (DSBs) catalyzed by the topoisomerase II-like enzymes, SPO11 and TOPVIBL, initiate meiotic recombination. Following DSB formation, the MRE11-RAD50-NBS1/Xrs2 (MRN/X) complex, along with EXO1 and DNA2, cleave the SPO11-DNA to generate 3′ single-stranded DNA (ssDNA) ends, which are prerequisite for meiotic DSB repair. In both yeast and mammals, MRE11 exhibits endonucleolytic cleavage of the 5′ terminated DNA strand in the vicinity of the DSBs and exonucleolytic resection from 3′ to 5′ towards the DSB ends. RAD50 is a structure maintenance of chromosome (SMC) related protein that contains one ATPase domain at its N- and C- terminal ends, respectively, Zn hook, and anti-parallel coiled coils. RAD50 plays a crucial role in facilitating the MRE11 nuclease activity on DSBs by ATP binding and hydrolysis. However, the in vivo function of Rad50 in mammalian germ cells, particularly its in vivo role in the resection of meiotic DSB ends at the molecular level remains elusive. Here, we performed END-seq with synchronized zygotene spermatocytes from control and germ cell specific Rad50 mutant (Rad50-sKO) mice. We find that the number of formed DSB in the mutant spermatocytes was reduced compared to control spermatocytes (6 636 DSBs in Rad50-sKO spermatocytes vs 8 168 in control spermatocytes) and abnormal DSB end resection occurred in mutant spermatocytes (DSB end resection length: 1 279 nts in Rad50-sKO spermatocytes vs 1 923 nts in control spermatocytes). Thus, RAD50 is essential for DSB formation and end resection during mammalian meiosis.

2024-04-02 | GSE262706 | GEO

DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells [END-seq]

Project description:DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells [END-seq]

| PRJNA772573 | ENA

Phosphoproteomic dataset comparing wild type, bob1-1 and bob1-1dbf4∆ cells in M-phase arrested S.cerevisiae.

2024-02-15 | PXD042607 | Pride