scholarly journals USP11 controls R-loops by regulating senataxin proteostasis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mateusz Jurga ◽  
Arwa A. Abugable ◽  
Alastair S. H. Goldman ◽  
Sherif F. El-Khamisy
Keyword(s):  
Ubiquitin Ligase ◽  
Protein Turnover ◽  
Neurological Disease ◽  
E3 Ubiquitin Ligase ◽  
Genomic Stability ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Steady State Levels ◽  
By Products ◽  
Dependent Mechanism

AbstractR-loops are by-products of transcription that must be tightly regulated to maintain genomic stability and gene expression. Here, we describe a mechanism for the regulation of the R-loop-specific helicase, senataxin (SETX), and identify the ubiquitin specific peptidase 11 (USP11) as an R-loop regulator. USP11 de-ubiquitinates SETX and its depletion increases SETX K48-ubiquitination and protein turnover. Loss of USP11 decreases SETX steady-state levels and reduces R-loop dissolution. Ageing of USP11 knockout cells restores SETX levels via compensatory transcriptional downregulation of the E3 ubiquitin ligase, KEAP1. Loss of USP11 reduces SETX enrichment at KEAP1 promoter, leading to R-loop accumulation, enrichment of the endonuclease XPF and formation of double-strand breaks. Overexpression of KEAP1 increases SETX K48-ubiquitination, promotes its degradation and R-loop accumulation. These data define a ubiquitination-dependent mechanism for SETX regulation, which is controlled by the opposing activities of USP11 and KEAP1 with broad applications for cancer and neurological disease.

scholarly journals βarrestin-1 regulates DNA repair by acting as an E3-ubiquitin ligase adaptor for 53BP1

2019 ◽  
Vol 27 (4) ◽  
pp. 1200-1213 ◽  
Author(s):  
Ainhoa Nieto ◽  
Makoto R. Hara ◽  
Victor Quereda ◽  
Wayne Grant ◽  
Vanessa Saunders ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ionizing Radiation ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Molecular Scaffold ◽  
Strand Breaks

Abstract Cellular DNA is constantly under threat from internal and external insults, consequently multiple pathways have evolved to maintain chromosomal fidelity. Our previous studies revealed that chronic stress, mediated by continuous stimulation of the β2-adrenergic-βarrestin-1 signaling axis suppresses activity of the tumor suppressor p53 and impairs genomic integrity. In this pathway, βarrestin-1 (βarr1) acts as a molecular scaffold to promote the binding and degradation of p53 by the E3-ubiquitin ligase, MDM2. We sought to determine whether βarr1 plays additional roles in the repair of DNA damage. Here we demonstrate that in mice βarr1 interacts with p53-binding protein 1 (53BP1) with major consequences for the repair of DNA double-strand breaks. 53BP1 is a principle component of the DNA damage response, and when recruited to the site of double-strand breaks in DNA, 53BP1 plays an important role coordinating repair of these toxic lesions. Here, we report that βarr1 directs 53BP1 degradation by acting as a scaffold for the E3-ubiquitin ligase Rad18. Consequently, knockdown of βarr1 stabilizes 53BP1 augmenting the number of 53BP1 DNA damage repair foci following exposure to ionizing radiation. Accordingly, βarr1 loss leads to a marked increase in irradiation resistance both in cells and in vivo. Thus, βarr1 is an important regulator of double strand break repair, and disruption of the βarr1/53BP1 interaction offers an attractive strategy to protect cells against high levels of exposure to ionizing radiation.

scholarly journals Tex19.1 Regulates Meiotic DNA Double Strand Break Frequency in Mouse Spermatocytes

2017 ◽  
Author(s):  
James H. Crichton ◽  
Christopher J. Playfoot ◽  
Marie MacLennan ◽  
David Read ◽  
Howard J. Cooke ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Meiotic Recombination ◽  
Homologous Chromosome ◽  
E3 Ubiquitin Ligase ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Genetic Pathway ◽  
Strand Breaks ◽  
Chromosome Synapsis ◽  
Meiotic Dsbs

AbstractMeiosis relies on the SPO11 endonuclease to generate the recombinogenic DNA double strand breaks (DSBs) required for homologous chromosome synapsis and segregation. The number of meiotic DSBs needs to be sufficient to allow chromosomes to search for and find their homologs, but not excessive to the point of causing genome instability. Here we report that meiotic DSB frequency in mouse spermatocytes is regulated by the mammal-specific gene Tex19.1. We show that the chromosome asynapsis previously reported in Tex19.1-/- spermatocytes is preceded by reduced numbers of recombination foci in leptotene and zygotene. Tex19.1 is required for the generation of normal levels of Spo11-dependent DNA damage during leptotene, but not for upstream events such as MEI4 foci formation or accumulation of H3K4me3 at recombination hotspots. Furthermore, we show that mice carrying mutations in the E3 ubiquitin ligase UBR2, a TEX19.1-interacting partner, phenocopy the Tex19.1-/- recombination defects. These data show that Tex19.1 and Ubr2 are required for mouse spermatocytes to generate sufficient meiotic DSBs to ensure that homology search is consistently successful, and reveal a hitherto unknown genetic pathway regulating meiotic DSB frequency in mammals.Author SummaryMeiosis is a specialised type of cell division that occurs during sperm and egg development to reduce chromosome number prior to fertilisation. Recombination is a key step in meiosis as it facilitates the pairing of homologous chromosomes prior to their reductional division, and generates new combinations of genetic alleles for transmission in the next generation. Regulating the amount of recombination is key for successful meiosis: too much will likely cause mutations, chromosomal re-arrangements and genetic instability, whereas too little causes defects in homologous chromosome pairing prior to the meiotic divisions. This study identifies a genetic pathway requiredto generate robust meiotic recombination in mouse spermatocytes. We show that male mice with mutations in Tex19.1 or Ubr2, which encodes an E3 ubiquitin ligase that interacts with TEX19.1, have defects in generating normal levels of meiotic recombination. We show that the defects in these mutants impact on the recombination process at the stage when programmed DNA double strand breaks are being made. This defect likely contributes to the chromosome synapsis and meiotic progression phenotypes previously described in these mutant mice. This study has implications for our understanding of how this fundamental aspect of genetics and inheritance is controlled.

scholarly journals Differential Roles of ATM- and Chk2-Mediated Phosphorylations of Hdmx in Response to DNA Damage

2006 ◽  
Vol 26 (18) ◽  
pp. 6819-6831 ◽  
Author(s):  
Yaron Pereg ◽  
Suzanne Lam ◽  
Amina Teunisse ◽  
Sharon Biton ◽  
Erik Meulmeester ◽  
...  
Keyword(s):  
Dna Damage ◽  
Protein Kinase ◽  
Posttranslational Modifications ◽  
Genomic Stability ◽  
Double Strand Breaks ◽  
Nuclear Accumulation ◽  
Strand Breaks ◽  
Damage Response ◽  
Subsequent Degradation ◽  
Atm Protein

ABSTRACT The p53 tumor suppressor plays a major role in maintaining genomic stability. Its activation and stabilization in response to double strand breaks (DSBs) in DNA are regulated primarily by the ATM protein kinase. ATM mediates several posttranslational modifications on p53 itself, as well as phosphorylation of p53's essential inhibitors, Hdm2 and Hdmx. Recently we showed that ATM- and Hdm2-dependent ubiquitination and subsequent degradation of Hdmx following DSB induction are mediated by phosphorylation of Hdmx on S403, S367, and S342, with S403 being targeted directly by ATM. Here we show that S367 phosphorylation is mediated by the Chk2 protein kinase, a downstream kinase of ATM. This phosphorylation, which is important for subsequent Hdmx ubiquitination and degradation, creates a binding site for 14-3-3 proteins which controls nuclear accumulation of Hdmx following DSBs. Phosphorylation of S342 also contributed to optimal 14-3-3 interaction and nuclear accumulation of Hdmx, but phosphorylation of S403 did not. Our data indicate that binding of a 14-3-3 dimer and subsequent nuclear accumulation are essential steps toward degradation of p53's inhibitor, Hdmx, in response to DNA damage. These results demonstrate a sophisticated control by ATM of a target protein, Hdmx, which itself is one of several ATM targets in the ATM-p53 axis of the DNA damage response.

IL-3 and Retinoic Acid-Induced Myeloid Differentiation of Hematopoietic Progenitors Is Negatively Regulated by E3 Ubiquitin Ligase Rnf41 (FLRF).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3160-3160
Author(s):  
Xin Jing ◽  
Luis Dabul ◽  
Ronald G. Nachtman ◽  
Roland Jurecic
Keyword(s):  
Retinoic Acid ◽  
Steady State ◽  
Ligand Binding ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Myeloid Differentiation ◽  
Hematopoietic Progenitors ◽  
Induced Differentiation ◽  
Gm Csf ◽  
Steady State Levels

Abstract The proliferation and differentiation of hematopoietic cells is regulated by interaction of diverse group of cytokines with corresponding receptors. Regulation of cytokine signaling occurs at multiple levels, including the regulation of the amount of receptors present before and after ligand binding. However, the mechanisms that govern pre-determined steady-state amount of cytokine receptors are poorly understood. Previously we have reported that new E3 ubiquitin ligase Rnf41 (FLRF/Nrdp1) regulates cytokine-induced differentiation of hematopoietic progenitors through negative regulation of steady-state receptor levels. Increased levels of Rnf41 protein significantly attenuate differentiation of multipotent progenitors in response to IL-3, Epo and GM-CSF, due to a significant and constitutive decrease in the steady-state amount of IL-3, Epo and GM-CSF receptors. Immunoprecipitation and Western analysis of proteins from several types of hematopoietic progenitors has confirmed that Rnf41 protein associates with IL-3, Epo and GM-CSF receptors, and has shown that Rnf41-mediated down-regulation of receptors is independent of the ligand binding. Thus, by regulating steady-state amounts of IL-3, Epo and GM-CSF receptors Rnf41 could be maintaining optimal levels of signaling necessary for proper lineage commitment and differentiation of HSC and progenitors. Retinoic acid (RA) is known to augment IL-3 and GM-CSF induced differentiation of progenitors into myeloid lineages. Surprisingly, instead of improving the RA treatment further suppressed IL-3 and GM-CSF-induced myeloid differentiation of hematopoietic progenitors over-expressing Rnf41. The RA functions through RARα and RXR receptors, whihc act as transcription factors and interact with specific DNA targets as hetero- (RAR-RXR) or homodimers (RXR-RXR). Interestingly, Western analysis has shown that hematopoietic progenitors over-expressing Rnf41 exhibit a reduction in the steady-state levels of RARα receptors, whereas levels of RXR receptors remain unchanged. Moreover, the treatment of hematopoietic progenitors over-expressing Rnf41 with RA leads to even further decrease of RARα receptor levels. The transient over-expression of Rnf41 in BaF3 cell line also decreases steady-state levels of RARα receptors, while RXR receptor levels remain unchanged. Protein IP with α-Rnf41, α-RARα or α-RXR antibodies has shown that endogenous Rnf41 protein associates with RARα receptors in hematopoietic progenitors. Taken together, these results suggest that Rnf41 influences RA-mediated myeloid differentiation of hematopoietic progenitors by negatively regulating the levels of RARα receptors. Several studies have reported that IL-3 and GM-CSF-induced myeloid differentiation of hematopoietic progenitors leads to activation of RARa through induction of the Jak2/Stat5 pathway. These studies have defined a previously unknown cytokine-RAR interaction during myelopoiesis and suggested that RAR activation might be a critical downstream event following IL-3 and GM-CSF signaling during myeloid differentiation. Combined together the existing data suggest a model in which Rnf41 negatively regulates myeloid differentiation of hematopoietic progenitors by independently regulating steady state levels of IL-3, GM-CSF and RAR receptors, and thus impacting cytokine and RA signaling. Ongoing studies with RA agonists and antagonists are aimed at unraveling further the role of Rnf41 in regulation of RA signaling during progenitor cell differentiation.

scholarly journals A Survey of Reported Disease-Related Mutations in the MRE11-RAD50-NBS1 Complex

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1678 ◽  
Author(s):  
Samiur Rahman ◽  
Marella D. Canny ◽  
Tanner A. Buschmann ◽  
Michael P. Latham
Keyword(s):  
Genomic Stability ◽  
Nijmegen Breakage Syndrome ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Response Factors ◽  
Strand Breaks ◽  
Mrn Complex ◽  
Damage Response ◽  
Biochemical Level

The MRE11-RAD50-NBS1 (MRN) protein complex is one of the primary vehicles for repairing DNA double strand breaks and maintaining the genomic stability within the cell. The role of the MRN complex to recognize and process DNA double-strand breaks as well as signal other damage response factors is critical for maintaining proper cellular function. Mutations in any one of the components of the MRN complex that effect function or expression of the repair machinery could be detrimental to the cell and may initiate and/or propagate disease. Here, we discuss, in a structural and biochemical context, mutations in each of the three MRN components that have been associated with diseases such as ataxia telangiectasia-like disorder (ATLD), Nijmegen breakage syndrome (NBS), NBS-like disorder (NBSLD) and certain types of cancers. Overall, deepening our understanding of disease-causing mutations of the MRN complex at the structural and biochemical level is foundational to the future aim of treating diseases associated with these aberrations.

DNA repair after oncological therapy (radiotherapy and chemotherapy)

2016 ◽  
pp. 82-85
Author(s):  
Ekkehard Dikomey ◽  
Kerstin Borgmann ◽  
Malte Kriegs ◽  
Wael Y. Mansour ◽  
Cordula Petersen ◽  
...  
Keyword(s):  
Dna Repair ◽  
Genomic Stability ◽  
Lethal Effect ◽  
Tumour Cells ◽  
Double Strand Breaks ◽  
Radiation Response ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Repair Mechanisms

The lethal effect of ionizing irradiation on tumour cells is mostly determined by the repair of DNA double-strand breaks (DSBs). Cells are able to repair most of the DSBs, but 1% to 3 % are either non- or mis-repaired, which will then give rise to lethal chromosomal aberrations. Cells have evolved complex DSB repair mechanisms with a stringent hierarchy to guarantee the genomic stability. However, in tumour cells both mechanisms as well as hierarchy are often disturbed. This knowledge is important for an understanding of the radiation response of tumours, but—most of all—for the establishment of new and specific targets for therapy.

scholarly journals 53BP1 Cooperates with p53 and Functions as a Haploinsufficient Tumor Suppressor in Mice

2005 ◽  
Vol 25 (22) ◽  
pp. 10079-10086 ◽  
Author(s):  
Irene M. Ward ◽  
Simone Difilippantonio ◽  
Kay Minn ◽  
Melissa D. Mueller ◽  
Julian R. Molina ◽  
...  
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Chromosome Structure ◽  
Genomic Stability ◽  
Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Histone H2ax ◽  
Structural Aberrations ◽  
Antigen Receptor Loci

ABSTRACT p53 binding protein 1 (53BP1) is a putative DNA damage sensor that accumulates at sites of double-strand breaks (DSBs) in a manner dependent on histone H2AX. Here we show that the loss of one or both copies of 53BP1 greatly accelerates lymphomagenesis in a p53-null background, suggesting that 53BP1 and p53 cooperate in tumor suppression. A subset of 53BP1−/− p53−/− lymphomas, like those in H2AX−/− p53−/− mice, were diploid and harbored clonal translocations involving antigen receptor loci, indicating misrepair of DSBs during V(D)J recombination as one cause of oncogenic transformation. Loss of a single 53BP1 allele compromised genomic stability and DSB repair, which could explain the susceptibility of 53BP1+/− mice to tumorigenesis. In addition to structural aberrations, there were high rates of chromosomal missegregation and accumulation of aneuploid cells in 53BP1−/− p53+/+ and 53BP1−/− p53−/− tumors as well as in primary 53BP1−/− splenocytes. We conclude that 53BP1 functions as a dosage-dependent caretaker that promotes genomic stability by a mechanism that preserves chromosome structure and number.

scholarly journals RanGTP aids anaphase entry through Ubr5-mediated protein turnover

2015 ◽  
Vol 211 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Hao Jiang ◽  
Xiaonan He ◽  
Di Feng ◽  
Xueliang Zhu ◽  
Yixian Zheng
Keyword(s):  
Molecular Mechanism ◽  
Ubiquitin Ligase ◽  
Protein Turnover ◽  
Spindle Assembly Checkpoint ◽  
E3 Ubiquitin Ligase ◽  
Direct Interaction ◽  
Spindle Assembly ◽  
Chromosome Congression

RanGTP is known to regulate the spindle assembly checkpoint (SAC), but the underlying molecular mechanism is unclear. BuGZ stabilizes SAC protein Bub3 through direct interaction and facilitates its mitotic function. Here we show that RanGTP promotes the turnover of BuGZ and Bub3 in metaphase, which in turn facilitates metaphase-to-anaphase transition. BuGZ and Bub3 interact with either importin-β or an E3 ubiquitin ligase, Ubr5. RanGTP promotes the dissociation of importin-β from BuGZ and Bub3 in metaphase. This results in increased binding of BuGZ and Bub3 to Ubr5, leading to ubiquitination and subsequent turnover of both proteins. We propose that elevated metaphase RanGTP levels use Ubr5 to couple overall chromosome congression to SAC silencing.

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