The Importance of ATM and ATR in Physcomitrella patens DNA Damage Repair, Development, and Gene Targeting

Coordinated by ataxia-telangiectasia-mutated (ATM) and ATM and Rad3-related (ATR), two highly conserved kinases, DNA damage repair ensures genome integrity and survival in all organisms. The Arabidopsis thaliana (A. thaliana) orthologues are well characterized and exhibit typical mammalian characteristics. We mutated the Physcomitrella patens (P. patens) PpATM and PpATR genes by deleting functionally important domains using gene targeting. Both mutants showed growth abnormalities, indicating that these genes, particularly PpATR, are important for normal vegetative development. ATR was also required for repair of both direct and replication-coupled double-strand breaks (DSBs) and dominated the transcriptional response to direct DSBs, whereas ATM was far less important, as shown by assays assessing resistance to DSB induction and SuperSAGE-based transcriptomics focused on DNA damage repair genes. These characteristics differed significantly from the A. thaliana genes but resembled those in yeast (Saccharomyces cerevisiae). PpATR was not important for gene targeting, pointing to differences in the regulation of gene targeting and direct DSB repair. Our analysis suggests that ATM and ATR functions can be substantially diverged between plants. The differences in ATM and ATR reflect the differences in DSB repair pathway choices between A. thaliana and P. patens, suggesting that they represent adaptations to different demands for the maintenance of genome stability.

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HP1β Chromo Shadow Domain facilitates H2A ubiquitination for BRCA1 recruitment at DNA double-strand breaks

10.1101/2022.01.11.475809 ◽

2022 ◽

Author(s):

Tej Pandita ◽

Vijay Kumari Charaka ◽

Sharmistha Chakraborty ◽

Chi-Lin Tsai ◽

Xiaoyan Wang ◽

...

Keyword(s):

Dna Damage ◽

Genome Stability ◽

Strand Break ◽

Dna Double Strand Breaks ◽

Dsb Repair ◽

Strand Breaks ◽

Damage Repair ◽

Dna Double Strand Break ◽

Assembly Factor ◽

Chromo Shadow Domain

Efficient DNA double strand break (DSB) repair by homologous recombination (HR), as orchestrated by histone and non-histone proteins, is critical to genome stability, replication, transcription, and cancer avoidance. Here we report that Heterochromatin Protein1 beta (HP1β) acts as a key component of the HR DNA resection step by regulating BRCA1 enrichment at DNA damage sites, a function largely dependent on the HP1β chromo shadow domain (CSD). HP1β itself is enriched at DSBs within gene-rich regions through a CSD interaction with Chromatin Assembly Factor 1 (CAF1) and HP1β depletion impairs subsequent BRCA1 enrichment. An added interaction of the HP1β CSD with the Polycomb Repressor Complex 1 ubiquitinase component RING1A facilitates BRCA1 recruitment by increasing H2A lysine 118-119 ubiquitination, a marker for BRCA1 recruitment. Our findings reveal that HP1β interactions, mediated through its CSD with RING1A, promote H2A ubiquitination and facilitate BRCA1 recruitment at DNA damage sites, a critical step in DSB repair by the HR pathway. These collective results unveil how HP1β is recruited to DSBs in gene-rich regions and how HP1β subsequently promotes BRCA1 recruitment to further HR DNA damage repair by stimulating CtIP-dependent resection.

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Relationships between chromatin remodeling and DNA damage repair induced by 8-methoxypsoralen and UVA in yeast Saccharomyces cerevisiae

Genetics and Molecular Biology ◽

10.1590/s1415-47572012000600021 ◽

2012 ◽

Vol 35 (4 suppl 1) ◽

pp. 1052-1059 ◽

Cited By ~ 3

Author(s):

Lavínia Almeida Cruz ◽

Temenouga Nikolova Guecheva ◽

Diego Bonato ◽

João Antônio Pêgas Henriques

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Damage ◽

Chromatin Remodeling ◽

Dna Damage Repair ◽

Yeast Saccharomyces Cerevisiae ◽

Damage Repair

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Differential Requirements for RAD51 in Physcomitrella patens and Arabidopsis thaliana Development and DNA Damage Repair

The Plant Cell ◽

10.1105/tpc.107.054049 ◽

2007 ◽

Vol 19 (10) ◽

pp. 3080-3089 ◽

Cited By ~ 31

Author(s):

Ulrich Markmann-Mulisch ◽

Edelgard Wendeler ◽

Oliver Zobell ◽

Gabriele Schween ◽

Hans-Henning Steinbiss ◽

...

Keyword(s):

Dna Damage ◽

Arabidopsis Thaliana ◽

Physcomitrella Patens ◽

Dna Damage Repair ◽

Damage Repair

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Regulation of Genome Stability by TEL1 and MEC1, Yeast Homologs of the Mammalian ATM and ATR Genes

Genetics ◽

10.1093/genetics/161.2.493 ◽

2002 ◽

Vol 161 (2) ◽

pp. 493-507

Author(s):

Rolf J Craven ◽

Patricia W Greenwell ◽

Margaret Dominska ◽

Thomas D Petes

Keyword(s):

Dna Damage ◽

Telomere Length ◽

Mammalian Cells ◽

Genome Stability ◽

Chromosome Loss ◽

Yeast Saccharomyces Cerevisiae ◽

Mutant Genotype ◽

Dna Damaging Agents ◽

Damage Repair ◽

Length Regulation

Abstract In eukaryotes, a family of related protein kinases (the ATM family) is involved in regulating cellular responses to DNA damage and telomere length. In the yeast Saccharomyces cerevisiae, two members of this family, TEL1 and MEC1, have functionally redundant roles in both DNA damage repair and telomere length regulation. Strains with mutations in both genes are very sensitive to DNA damaging agents, have very short telomeres, and undergo cellular senescence. We find that strains with the double mutant genotype also have ∼80-fold increased rates of mitotic recombination and chromosome loss. In addition, the tel1 mec1 strains have high rates of telomeric fusions, resulting in translocations, dicentrics, and circular chromosomes. Similar chromosome rearrangements have been detected in mammalian cells with mutations in ATM (related to TEL1) and ATR (related to MEC1) and in mammalian cells that approach cell crisis.

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Nuclear localization of Beclin 1 promotes radiation-induced DNA damage repair independent of autophagy

Scientific Reports ◽

10.1038/srep45385 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 13

Author(s):

Fei Xu ◽

Yixuan Fang ◽

Lili Yan ◽

Lan Xu ◽

Suping Zhang ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Repair ◽

Strand Break ◽

Beclin 1 ◽

Dsb Repair ◽

Dna Topoisomerase ◽

Damage Repair ◽

Dna Double Strand Break ◽

Radiation Induced

Abstract Beclin 1 is a well-established core mammalian autophagy protein that is embryonically indispensable and has been presumed to suppress oncogenesis via an autophagy-mediated mechanism. Here, we show that Beclin 1 is a prenatal primary cytoplasmic protein but rapidly relocated into the nucleus during postnatal development in mice. Surprisingly, deletion of beclin1 in in vitro human cells did not block an autophagy response, but attenuated the expression of several DNA double-strand break (DSB) repair proteins and formation of repair complexes, and reduced an ability to repair DNA in the cells exposed to ionizing radiation (IR). Overexpressing Beclin 1 improved the repair of IR-induced DSB, but did not restore an autophagy response in cells lacking autophagy gene Atg7, suggesting that Beclin 1 may regulate DSB repair independent of autophagy in the cells exposed to IR. Indeed, we found that Beclin 1 could directly interact with DNA topoisomerase IIβ and was recruited to the DSB sites by the interaction. These findings reveal a novel function of Beclin 1 in regulation of DNA damage repair independent of its role in autophagy particularly when the cells are under radiation insult.

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Redox regulation of genome stability by effects on gene expression, epigenetic pathways and DNA damage/repair

Redox Biology ◽

10.1016/j.redox.2015.05.008 ◽

2015 ◽

Vol 5 ◽

pp. 275-289 ◽

Cited By ~ 80

Author(s):

Yuliya Mikhed ◽

Agnes Görlach ◽

Ulla G. Knaus ◽

Andreas Daiber

Keyword(s):

Gene Expression ◽

Dna Damage ◽

Genome Stability ◽

Redox Regulation ◽

Dna Damage Repair ◽

Damage Repair

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Thrombopoietin-Increased DNA-PK-Dependent DNA Repair Limits Hematopoietic STEM and Progenitor CELL Mutagenesis in Response to Irradiation

Blood ◽

10.1182/blood.v120.21.3447.3447 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3447-3447

Author(s):

Bérengère de Laval ◽

Patrycja Pawlikowska ◽

Benoit Roch ◽

Laurence Petit-Cocault ◽

Chrystele Bilhou-Nabera ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Dna Damage Response ◽

Dna Damage Repair ◽

Dsb Repair ◽

Hematopoietic Stem ◽

Damage Repair ◽

Damage Response ◽

Radiation Induced

Abstract Abstract 3447 Radiation-induced double-strand breaks (DSBs) represent a serious threat to the preservation of genetic information when it reaches hematopoietic stem cells (HSCs). Residual loss of HSC functions and increased risk of developing hematopoietic malignancies are two concerning complications of anti-cancer radiotherapy. Management of acute myelosuppression following radio- or chemotherapy has been significantly improved in recent years by the use of growth factors. However, how cytokine/environmental signals integrate the DNA damage responses in HSCs and regulate the long-term residual HSC defects following radio-or chemotherapy is unknown. Notably, the contribution of cytokines regulating HSC functions to HSC intrinsic DNA damage repair processes remains to be delineated. Thrombopoietin (TPO) and its receptor, Mpl, are critical factors supporting HSC self-renewal, survival and expansion posttransplantation. In this study, we uncover an unknown and unique function for TPO/Mpl in the regulation the DNA damage response. We show that DSB repair, measured by both γH2Ax foci resolution and neutral comet assays, following γ-irradiation (IR) or topoisomerase II inhibitor treatments, is defective in Mpl−/− and Mpl+/− HS and progenitor cells (HSPCs). Similar defects were found in wild-type cells treated in the absence of TPO. This indicates that the impaired DNA repair of Mpl−/− and Mpl+/− cells results from a specific loss of TPO-mediated DNA damage response signaling at the time of IR rather than from intrinsic constitutive differences. TPO stimulates DNA repair by increasing IR-induced DNA-PK phosphorylation at Ser2056 and Thr2609 and non-homologous end joining (NHEJ) efficiency in both HSPCs and the human UT7-Mpl cell line. This is to our knowledge the first demonstration that a cytokine involved in the homeostatic maintenance of HSCs may also regulate their response to external DNA damaging insults by controlling the DSB repair machinery. Short TPO treatment in vitro or single TPO injection to TPO/Mpl proficient mice prior to sublethal total body IR reduced IR-induced HSC genomic instability and loss of long-term reconstitution ability. This may open new avenues for administration of TPO agonists before radiotherapy to minimize radiation-induced HSC injury and mutagenesis. In addition, since Mpl is haploinsufficient in the regulation of DNA damage repair, these data suggest that Mpl might also act as a tumor suppressor in response to radiotherapy. Disclosures: No relevant conflicts of interest to declare.

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