Correction of the DNA repair defect in xeroderma pigmentosum group E by injection of a DNA damage-binding protein.

Protein disulphide isomerase (PDI) is a chaperone that catalyses the formation of thiol-disulphide bonds during protein folding. Whilst up-regulation of PDI is a protective mechanism to regulate protein folding, an increasingly wide range of cellular functions have been ascribed to PDI. Originally identified in the endoplasmic reticulum (ER), PDI has now been detected in many cellular locations, including the nucleus. However, its role in this cellular compartment remains undefined. PDI is implicated in multiple diseases, including amyotrophic lateral sclerosis (ALS), a fatal and rapidly progressing neurodegenerative condition affecting motor neurons. Loss of essential proteins from the nucleus is an important feature of ALS. This includes TAR DNA-binding protein-43 (TDP-43), a DNA/RNA binding protein present in a pathological form in the cytoplasm in almost all (97%) ALS cases, that is also mutated in a proportion of familial cases. PDI is protective against disease-relevant phenotypes associated with dysregulation of protein homeostasis (proteostasis) in ALS. DNA damage is also increasingly linked to ALS, which is induced by pathological forms of TDP-43 by impairment of its normal function in the non-homologous end-joining (NHEJ) mechanism of DNA repair. However, it remains unclear whether PDI is protective against DNA damage in ALS. In this study we demonstrate that PDI was protective against several types of DNA damage, induced by either etoposide, hydrogen peroxide (H2O2), or ALS-associated mutant TDP-43M337V in neuronal cells. This was demonstrated using widely used DNA damage markers, phosphorylated H2AX and 53BP1, which is specific for NHEJ. Moreover, we also show that PDI translocates into the nucleus following DNA damage. Here PDI is recruited directly to sites of DNA damage, implying that it has a direct role in DNA repair. This study therefore identifies a novel role of PDI in the nucleus in preventing DNA damage.

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Tissue-infiltrating macrophages mediate an exosome-based metabolic reprogramming upon DNA damage

Nature Communications ◽

10.1038/s41467-019-13894-9 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 13

Author(s):

Evi Goulielmaki ◽

Anna Ioannidou ◽

Maria Tsekrekou ◽

Kalliopi Stratigi ◽

Ioanna K. Poutakidou ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Glucose Transporter ◽

Ex Vivo ◽

Disease Onset ◽

Metabolic Reprogramming ◽

Inflammatory Stimuli ◽

Underlying Mechanisms ◽

Repair Defect

AbstractDNA damage and metabolic disorders are intimately linked with premature disease onset but the underlying mechanisms remain poorly understood. Here, we show that persistent DNA damage accumulation in tissue-infiltrating macrophages carrying an ERCC1-XPF DNA repair defect (Er1F/−) triggers Golgi dispersal, dilation of endoplasmic reticulum, autophagy and exosome biogenesis leading to the secretion of extracellular vesicles (EVs) in vivo and ex vivo. Macrophage-derived EVs accumulate in Er1F/− animal sera and are secreted in macrophage media after DNA damage. The Er1F/− EV cargo is taken up by recipient cells leading to an increase in insulin-independent glucose transporter levels, enhanced cellular glucose uptake, higher cellular oxygen consumption rate and greater tolerance to glucose challenge in mice. We find that high glucose in EV-targeted cells triggers pro-inflammatory stimuli via mTOR activation. This, in turn, establishes chronic inflammation and tissue pathology in mice with important ramifications for DNA repair-deficient, progeroid syndromes and aging.

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At the Interface of Three Nucleic Acids: The Role of RNA-Binding Proteins and Poly(ADP-ribose) in DNA Repair

Acta Naturae ◽

10.32607/20758251-2017-9-2-4-16 ◽

2017 ◽

Vol 9 (2) ◽

pp. 4-16 ◽

Cited By ~ 9

Author(s):

E. E. Alemasova ◽

O. I. Lavrik

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Binding Protein ◽

Regulation Of Gene Expression ◽

Rna Granules ◽

Dna And Rna ◽

Cytoplasmic Rna

RNA-binding proteins (RBPs) regulate RNA metabolism, from synthesis to decay. When bound to RNA, RBPs act as guardians of the genome integrity at different levels, from DNA damage prevention to the post-transcriptional regulation of gene expression. Recently, RBPs have been shown to participate in DNA repair. This fact is of special interest as DNA repair pathways do not generally involve RNA. DNA damage in higher organisms triggers the formation of the RNA-like polymer - poly(ADP-ribose) (PAR). Nucleic acid-like properties allow PAR to recruit DNA- and RNA-binding proteins to the site of DNA damage. It is suggested that poly(ADP-ribose) and RBPs not only modulate the activities of DNA repair factors, but that they also play an important role in the formation of transient repairosome complexes in the nucleus. Cytoplasmic biomolecules are subjected to similar sorting during the formation of RNA assemblages by functionally related mRNAs and promiscuous RBPs. The Y-box-binding protein 1 (YB-1) is the major component of cytoplasmic RNA granules. Although YB-1 is a classic RNA-binding protein, it is now regarded as a non-canonical factor of DNA repair.

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DNA Polymerase B1 Binding Protein 1 Is Important for DNA Repair by Holoenzyme PolB1 in the Extremely Thermophilic Crenarchaeon Sulfolobus acidocaldarius

Microorganisms ◽

10.3390/microorganisms9020439 ◽

2021 ◽

Vol 9 (2) ◽

pp. 439

Author(s):

Hiroka Miyabayashi ◽

Hiroyuki D. Sakai ◽

Norio Kurosawa

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Dna Polymerase ◽

Binding Protein ◽

Polymerase Activity ◽

Sulfolobus Acidocaldarius ◽

Deletion Strain ◽

Synthesis Activity ◽

Core Activity

DNA polymerase B1 (PolB1) is a member of the B-family DNA polymerase family and is a replicative DNA polymerase in Crenarchaea. PolB1 is responsible for the DNA replication of both the leading and lagging strands in the thermophilic crenarchaeon Sulfolobus acidocaldarius. Recently, two subunits, PolB1-binding protein (PBP)1 and PBP2, were identified in Saccharolobus solfataricus. Previous in vitro studies suggested that PBP1 and PBP2 influence the core activity of apoenzyme PolB1 (apo-PolB1). PBP1 contains a C-terminal acidic tail and modulates the strand-displacement synthesis activity of PolB1 during the synthesis of Okazaki fragments. PBP2 modestly enhances the DNA polymerase activity of apo-PolB1. These subunits are present in Sulfolobales, Acidilobales, and Desulfurococcales, which belong to Crenarchaea. However, it has not been determined whether these subunits are essential for the activity of apo-PolB1. In this study, we constructed a pbp1 deletion strain in S. acidocaldarius and characterized its phenotypes. However, a pbp2 deletion strain was not obtained, indicating that PBP2 is essential for replication by holoenzyme PolB1. A pbp1 deletion strain was sensitive to various types of DNA damage and exhibited an increased mutation rate, suggesting that PBP1 contribute to the repair or tolerance of DNA damage by holoenzyme PolB1. The results of our study suggest that PBP1 is important for DNA repair by holoenzyme PolB1 in S. acidocaldarius.

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