scholarly journals Genome integrity and neurogenesis of postnatal hippocampal neural stem/progenitor cells require a unique regulator Filia

2020 ◽  
Vol 6 (44) ◽  
pp. eaba0682 ◽  
Author(s):  
Jingzheng Li ◽  
Yafang Shang ◽  
Lin Wang ◽  
Bo Zhao ◽  
Chunli Sun ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Neurodevelopmental Disorders ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Replication Forks ◽  
Proof Of Concept ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Neural Stem Progenitor Cells

Endogenous DNA double-strand breaks (DSBs) formation and repair in neural stem/progenitor cells (NSPCs) play fundamental roles in neurogenesis and neurodevelopmental disorders. NSPCs exhibit heterogeneity in terms of lineage fates and neurogenesis activity. Whether NSPCs also have heterogeneous regulations on DSB formation and repair to accommodate region-specific neurogenesis has not been explored. Here, we identified a regional regulator Filia, which is predominantly expressed in mouse hippocampal NSPCs after birth and regulates DNA DSB formation and repair. On one hand, Filia protects stalling replication forks and prevents the replication stress-associated DNA DSB formation. On the other hand, Filia facilitates the homologous recombination–mediated DNA DSB repair. Consequently, Filia−/− mice had impaired hippocampal NSPC proliferation and neurogenesis and were deficient in learning, memory, and mood regulations. Thus, our study provided the first proof of concept demonstrating the region-specific regulations of DSB formation and repair in subtypes of NSPCs.

scholarly journals RSC Mobilizes Nucleosomes To Improve Accessibility of Repair Machinery to the Damaged Chromatin

2006 ◽  
Vol 27 (5) ◽  
pp. 1602-1613 ◽  
Author(s):  
Eun Yong Shim ◽  
Soo Jin Hong ◽  
Ji-Hyun Oum ◽  
Yvonne Yanez ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Base Pairs ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Free Dna ◽  
Key Questions

ABSTRACT Repair of DNA double-strand breaks (DSBs) protects cells and organisms, as well as their genome integrity. Since DSB repair occurs in the context of chromatin, chromatin must be modified to prevent it from inhibiting DSB repair. Evidence supports the role of histone modifications and ATP-dependent chromatin remodeling in repair and signaling of chromosome DSBs. The key questions are, then, what the nature of chromatin altered by DSBs is and how remodeling of chromatin facilitates DSB repair. Here we report a chromatin alteration caused by a single HO endonuclease-generated DSB at the Saccharomyces cerevisiae MAT locus. The break induces rapid nucleosome migration to form histone-free DNA of a few hundred base pairs immediately adjacent to the break. The DSB-induced nucleosome repositioning appears independent of end processing, since it still occurs when the 5′-to-3′ degradation of the DNA end is markedly reduced. The tetracycline-controlled depletion of Sth1, the ATPase of RSC, or deletion of RSC2 severely reduces chromatin remodeling and loading of Mre11 and Yku proteins at the DSB. Depletion of Sth1 also reduces phosphorylation of H2A, processing, and joining of DSBs. We propose that RSC-mediated chromatin remodeling at the DSB prepares chromatin to allow repair machinery to access the break and is vital for efficient DSB repair.

scholarly journals Human RNF169 is a negative regulator of the ubiquitin-dependent response to DNA double-strand breaks

2012 ◽  
Vol 197 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Maria Poulsen ◽  
Claudia Lukas ◽  
Jiri Lukas ◽  
Simon Bekker-Jensen ◽  
Niels Mailand
Keyword(s):  
Deoxyribonucleic Acid ◽  
Double Strand Breaks ◽  
Negative Regulator ◽  
Nonhomologous End Joining ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Protein Recruitment

Nonproteolytic ubiquitylation of chromatin surrounding deoxyribonucleic acid double-strand breaks (DSBs), mediated by the RNF8/RNF168 ubiquitin ligases, plays a key role in recruiting repair factors, including 53BP1 and BRCA1, to reestablish genome integrity. In this paper, we show that human RNF169, an uncharacterized E3 ubiquitin ligase paralogous to RNF168, accumulated in DSB repair foci through recognition of RNF168-catalyzed ubiquitylation products by its motif interacting with ubiquitin domain. Unexpectedly, RNF169 was dispensable for chromatin ubiquitylation and ubiquitin-dependent accumulation of repair factors at DSB sites. Instead, RNF169 functionally competed with 53BP1 and RAP80–BRCA1 for association with RNF168-modified chromatin independent of its catalytic activity, limiting the magnitude of their recruitment to DSB sites. By delaying accumulation of 53BP1 and RAP80 at damaged chromatin, RNF169 stimulated homologous recombination and restrained nonhomologous end joining, affecting cell survival after DSB infliction. Our results show that RNF169 functions in a noncanonical fashion to harness RNF168-mediated protein recruitment to DSB-containing chromatin, thereby contributing to regulation of DSB repair pathway utilization.

scholarly journals DNA Double-Strand Break Repair: All Roads Lead to HeterochROMAtin Marks

2021 ◽  
Vol 12 ◽  
Author(s):  
Pierre Caron ◽  
Enrico Pobega ◽  
Sophie E. Polo
Keyword(s):  
De Novo ◽  
Current Knowledge ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Dna Double Strand Break ◽  
The Impact

In response to DNA double-strand breaks (DSBs), chromatin modifications orchestrate DNA repair pathways thus safeguarding genome integrity. Recent studies have uncovered a key role for heterochromatin marks and associated factors in shaping DSB repair within the nucleus. In this review, we present our current knowledge of the interplay between heterochromatin marks and DSB repair. We discuss the impact of heterochromatin features, either pre-existing in heterochromatin domains or de novo established in euchromatin, on DSB repair pathway choice. We emphasize how heterochromatin decompaction and mobility further support DSB repair, focusing on recent mechanistic insights into these processes. Finally, we speculate about potential molecular players involved in the maintenance or the erasure of heterochromatin marks following DSB repair, and their implications for restoring epigenome function and integrity.

scholarly journals Transcription-associated processes cause DNA double-strand breaks and translocations in neural stem/progenitor cells

2016 ◽  
Vol 113 (8) ◽  
pp. 2258-2263 ◽  
Author(s):  
Bjoern Schwer ◽  
Pei-Chi Wei ◽  
Amelia N. Chang ◽  
Jennifer Kao ◽  
Zhou Du ◽  
...  
Keyword(s):  
B Cells ◽  
Progenitor Cells ◽  
Great Majority ◽  
Cell Types ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Transcription Profiles ◽  
Neural Stem Progenitor Cells

High-throughput, genome-wide translocation sequencing (HTGTS) studies of activated B cells have revealed that DNA double-strand breaks (DSBs) capable of translocating to defined bait DSBs are enriched around the transcription start sites (TSSs) of active genes. We used the HTGTS approach to investigate whether a similar phenomenon occurs in primary neural stem/progenitor cells (NSPCs). We report that breakpoint junctions indeed are enriched around TSSs that were determined to be active by global run-on sequencing analyses of NSPCs. Comparative analyses of transcription profiles in NSPCs and B cells revealed that the great majority of TSS-proximal junctions occurred in genes commonly expressed in both cell types, possibly because this common set has higher transcription levels on average than genes transcribed in only one or the other cell type. In the latter context, among all actively transcribed genes containing translocation junctions in NSPCs, those with junctions located within 2 kb of the TSS show a significantly higher transcription rate on average than genes with junctions in the gene body located at distances greater than 2 kb from the TSS. Finally, analysis of repair junction signatures of TSS-associated translocations in wild-type versus classical nonhomologous end-joining (C-NHEJ)–deficient NSPCs reveals that both C-NHEJ and alternative end-joining pathways can generate translocations by joining TSS-proximal DSBs to DSBs on other chromosomes. Our studies show that the generation of transcription-associated DSBs is conserved across divergent cell types.

scholarly journals Autophosphorylation of DNA-PKCS regulates its dynamics at DNA double-strand breaks

2007 ◽  
Vol 177 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Naoya Uematsu ◽  
Eric Weterings ◽  
Ken-ichi Yano ◽  
Keiko Morotomi-Yano ◽  
Burkhard Jakob ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Laser System ◽  
Double Strand Breaks ◽  
Dependent Manner ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Dna Ends

The DNA-dependent protein kinase catalytic subunit (DNA-PKCS) plays an important role during the repair of DNA double-strand breaks (DSBs). It is recruited to DNA ends in the early stages of the nonhomologous end-joining (NHEJ) process, which mediates DSB repair. To study DNA-PKCS recruitment in vivo, we used a laser system to introduce DSBs in a specified region of the cell nucleus. We show that DNA-PKCS accumulates at DSB sites in a Ku80-dependent manner, and that neither the kinase activity nor the phosphorylation status of DNA-PKCS influences its initial accumulation. However, impairment of both of these functions results in deficient DSB repair and the maintained presence of DNA-PKCS at unrepaired DSBs. The use of photobleaching techniques allowed us to determine that the kinase activity and phosphorylation status of DNA-PKCS influence the stability of its binding to DNA ends. We suggest a model in which DNA-PKCS phosphorylation/autophosphorylation facilitates NHEJ by destabilizing the interaction of DNA-PKCS with the DNA ends.

scholarly journals RAP80 suppresses the vulnerability of R-loops during DNA double-strand break repair

2021 ◽  
Author(s):  
Takaaki Yasuhara ◽  
Reona Kato ◽  
Motohiro Yamauchi ◽  
Yuki Uchihara ◽  
Lee Zou ◽  
...  
Keyword(s):  
Active Regions ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Critical Component ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Chromosome Translocations ◽  
Dna Double Strand Break

AbstractR-loops, consisting of ssDNA and DNA-RNA hybrids, are potentially vulnerable unless they are appropriately processed. Recent evidence suggests that R-loops can form in the proximity of DNA double-strand breaks (DSBs) within transcriptionally active regions. Yet, how the vulnerability of R-loops is overcome during DSB repair remains unclear. Here, we identify RAP80 as a factor suppressing the vulnerability of ssDNA in R-loops and chromosome translocations and deletions during DSB repair. Mechanistically, RAP80 prevents unscheduled nucleolytic processing of ssDNA in R-loops by CtIP. This mechanism promotes efficient DSB repair via transcription-associated end-joining dependent on BRCA1, Polθ, and LIG1/3. Thus, RAP80 suppresses the vulnerability of R-loops during DSB repair, thereby precluding genomic abnormalities in a critical component of the genome caused by deleterious R-loop processing.

scholarly journals Genome-wide mapping implicates R-loops in lineage-specific processes and formation of DNA break hotspots in neural stem/progenitor cells

2021 ◽  
Author(s):  
Supawat Thongthip ◽  
Annika Carlson ◽  
Madzia P. Crossley ◽  
Bjoern Schwer
Keyword(s):  
Progenitor Cells ◽  
Cluster Formation ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Neural Genes ◽  
Genome Wide ◽  
Gc Skew ◽  
Neural Stem Progenitor Cells ◽  
Dna Break

ABSTRACTRecent work has revealed classes of recurrent DNA double-strand breaks (DSBs) in neural stem/progenitor cells, including transcription-associated, promoter-proximal breaks and recurrent DSB clusters in late-replicating, long neural genes. However, the mechanistic factors promoting these different classes of DSBs in neural stem/progenitor cells are not understood. Here, we elucidated the genome-wide landscape of DNA:RNA hybrid structures called “R-loops” in primary neural stem/progenitor cells in order to assess their contribution to the different classes of DNA break “hotspots”. We report that R-loops in neural stem/progenitor cells are associated primarily with transcribed regions that replicate early and genes that show GC skew in their promoter region. Surprisingly, the majority of genes with recurrent DSB clusters in long, neural genes does not show substantial R-loop accumulation. We implicate R-loops in promoter-proximal DNA break formation in highly transcribed, early replicating regions and conclude that R-loops are not a driver of recurrent double-strand break cluster formation in most long, neural genes. Together, our study provides an understanding of how R-loops may contribute to DNA break hotspots and affect lineage-specific processes in neural stem/progenitor cells.

scholarly journals ATM’s Role in the Repair of DNA Double-Strand Breaks

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1370
Author(s):  
Atsushi Shibata ◽  
Penny A. Jeggo
Keyword(s):  
Stress Responses ◽  
Ataxia Telangiectasia ◽  
Cell Cycle Checkpoint ◽  
Double Strand Breaks ◽  
Multiple Roles ◽  
Dna Double Strand Breaks ◽  
Ataxia Telangiectasia Mutated ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Cycle Checkpoint

Ataxia telangiectasia mutated (ATM) is a central kinase that activates an extensive network of responses to cellular stress via a signaling role. ATM is activated by DNA double strand breaks (DSBs) and by oxidative stress, subsequently phosphorylating a plethora of target proteins. In the last several decades, newly developed molecular biological techniques have uncovered multiple roles of ATM in response to DNA damage—e.g., DSB repair, cell cycle checkpoint arrest, apoptosis, and transcription arrest. Combinational dysfunction of these stress responses impairs the accuracy of repair, consequently leading to dramatic sensitivity to ionizing radiation (IR) in ataxia telangiectasia (A-T) cells. In this review, we summarize the roles of ATM that focus on DSB repair.

Sign in / Sign up

Export Citation Format

Share Document