Regulation of non-homologous end joining via post-translational modifications of components of the ligation step

2016 ◽  
Vol 63 (4) ◽  
pp. 591-605 ◽  
Author(s):  
Kristína Durdíková ◽  
Miroslav Chovanec
Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1699 ◽  
Author(s):  
Lanni Aquila ◽  
Boyko S. Atanassov

Eukaryotic cells are constantly exposed to both endogenous and exogenous stressors that promote the induction of DNA damage. Of this damage, double strand breaks (DSBs) are the most lethal and must be efficiently repaired in order to maintain genomic integrity. Repair of DSBs occurs primarily through one of two major pathways: non-homologous end joining (NHEJ) or homologous recombination (HR). The choice between these pathways is in part regulated by histone post-translational modifications (PTMs) including ubiquitination. Ubiquitinated histones not only influence transcription and chromatin architecture at sites neighboring DSBs but serve as critical recruitment platforms for repair machinery as well. The reversal of these modifications by deubiquitinating enzymes (DUBs) is increasingly being recognized in a number of cellular processes including DSB repair. In this context, DUBs ensure proper levels of ubiquitin, regulate recruitment of downstream effectors, dictate repair pathway choice, and facilitate appropriate termination of the repair response. This review outlines the current understanding of histone ubiquitination in response to DSBs, followed by a comprehensive overview of the DUBs that catalyze the removal of these marks.


DNA Repair ◽  
2007 ◽  
Vol 6 (12) ◽  
pp. 1890-1893 ◽  
Author(s):  
Miroslav Chovanec ◽  
Thomas E. Wilson

2021 ◽  
Author(s):  
Gianluca Sigismondo ◽  
Lavinia Arseni ◽  
Thomas G Hofmann ◽  
Martina Seiffert ◽  
Jeroen Krijgsveld

The DNA damage response (DDR) is essential to maintain genome stability, and its deregulation predisposes to carcinogenesis while encompassing attractive targets for cancer therapy. Chromatin governs the DDR via interplay among all chromatin layers including DNA, histones post-translational modifications (hPTMs), and chromatin-associated proteins. Here we employ multi-layered proteomics to characterize chromatin-mediated interactions of repair proteins, signatures of hPTMs, and the DNA-bound proteome during DNA double-strand break repair at high temporal resolution. We functionally attribute novel chromatin-associated proteins to repair by non-homologous end-joining or homologous recombination (HR) revealing histone reader ATAD2, microtubule organizer TPX2 and histone methyltransferase G9A as regulators of HR and PARP inhibitor sensitivity. Furthermore, we dynamically profile numerous hPTMs at γH2AX-mononucleosomes during the DDR. Integration of these complementary data implicated G9A-mediated monomethylation of H3K56 in HR. Collectively, we provide a dynamic chromatin-centered view of DDR, while representing a valuable resource for the use of PARP inhibitors in cancer.


2020 ◽  
Vol 9 ◽  
Author(s):  
Jerome Lacombe ◽  
Titouan Cretignier ◽  
Laetitia Meli ◽  
E. M. Kithsiri Wijeratne ◽  
Jean-Luc Veuthey ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1506
Author(s):  
Angelos Papaspyropoulos ◽  
Nefeli Lagopati ◽  
Ioanna Mourkioti ◽  
Andriani Angelopoulou ◽  
Spyridon Kyriazis ◽  
...  

Protection of genome integrity is vital for all living organisms, particularly when DNA double-strand breaks (DSBs) occur. Eukaryotes have developed two main pathways, namely Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR), to repair DSBs. While most of the current research is focused on the role of key protein players in the functional regulation of DSB repair pathways, accumulating evidence has uncovered a novel class of regulating factors termed non-coding RNAs. Non-coding RNAs have been found to hold a pivotal role in the activation of DSB repair mechanisms, thereby safeguarding genomic stability. In particular, long non-coding RNAs (lncRNAs) have begun to emerge as new players with vast therapeutic potential. This review summarizes important advances in the field of lncRNAs, including characterization of recently identified lncRNAs, and their implication in DSB repair pathways in the context of tumorigenesis.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joonas A. Jamsen ◽  
Akira Sassa ◽  
Lalith Perera ◽  
David D. Shock ◽  
William A. Beard ◽  
...  

AbstractReactive oxygen species (ROS) oxidize cellular nucleotide pools and cause double strand breaks (DSBs). Non-homologous end-joining (NHEJ) attaches broken chromosomal ends together in mammalian cells. Ribonucleotide insertion by DNA polymerase (pol) μ prepares breaks for end-joining and this is required for successful NHEJ in vivo. We previously showed that pol μ lacks discrimination against oxidized dGTP (8-oxo-dGTP), that can lead to mutagenesis, cancer, aging and human disease. Here we reveal the structural basis for proficient oxidized ribonucleotide (8-oxo-rGTP) incorporation during DSB repair by pol μ. Time-lapse crystallography snapshots of structural intermediates during nucleotide insertion along with computational simulations reveal substrate, metal and side chain dynamics, that allow oxidized ribonucleotides to escape polymerase discrimination checkpoints. Abundant nucleotide pools, combined with inefficient sanitization and repair, implicate pol μ mediated oxidized ribonucleotide insertion as an emerging source of widespread persistent mutagenesis and genomic instability.


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