scholarly journals Method for assessment of nucleotide excision repair system efficiency ex vivo

Acta Naturae ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 122-125
Author(s):  
Aleksei A. Popov ◽  
Konstantin E. Orishchenko ◽  
Konstantin N. Naumenko ◽  
Aleksei N. Evdokimov ◽  
Irina O. Petruseva ◽  
...  
Keyword(s):  
Nucleotide Excision Repair ◽  
Fluorescent Protein ◽  
Excision Repair ◽  
Ex Vivo ◽  
Gene Promoter ◽  
Dna Lesions ◽  
Repair System ◽  
Wide Range ◽  
Nucleotide Excision ◽  
Living Organisms

The nucleotide excision repair (NER) is one of the main repair systems present in the cells of living organisms. It is responsible for the removal of a wide range of bulky DNA lesions. We succeeded in developing a method for assessing the efficiency of NER in the cell (ex vivo), which is a method based on the recovery of TagRFP fluorescent protein production through repair of the damage that blocks the expression of the appropriate gene. Our constructed plasmids containing bulky nFlu or nAnt lesions near the tagrfp gene promoter were shown to undergo repair in eukaryotic cells (HEK 293T) and that they can be used to analyze the efficiency of NER ex vivo. A comparative analysis of the time dependence of fluorescent cells accumulation after transfection with nFlu- and nAnt-DNA revealed that there are differences in how efficient their repair by the NER system of HEK 293T cells can be. The method can be used to assess the cell repair status and the repair efficiency of different structural damages.

Recognition and Removal of Bulky DNA Lesions by the Nucleotide Excision Repair System

2010 ◽  
pp. 261-298 ◽  
Author(s):  
Yuqin Cai ◽  
Konstantin Kropachev ◽  
Marina Kolbanovskiy ◽  
Alexander Kolbanovskiy ◽  
Suse Broyde ◽  
...  
Keyword(s):  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Lesions ◽  
Repair System ◽  
Nucleotide Excision ◽  
Nucleotide Excision Repair System ◽  
Bulky Dna Lesions

Circulating human B lymphocytes are deficient in nucleotide excision repair and accumulate mutations upon proliferation

Blood ◽  
2011 ◽  
Vol 117 (23) ◽  
pp. 6277-6286 ◽  
Author(s):  
Nevila Hyka-Nouspikel ◽  
Kimon Lemonidis ◽  
Wei-Ting Lu ◽  
Thierry Nouspikel
Keyword(s):  
Cell Cycle ◽  
B Lymphocytes ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Point Mutations ◽  
Dna Lesions ◽  
Repair System ◽  
Differentiated Cells ◽  
Nucleotide Excision ◽  
Dividing Cells

Abstract Faithful repair of DNA lesions is a crucial task that dividing cells must actively perform to maintain genome integrity. Strikingly, nucleotide excision repair (NER), the most versatile DNA repair system, is specifically down-regulated in terminally differentiated cells. This prompted us to examine whether NER attenuation might be a common feature of all G0-arrested cells, and in particular of those that retain the capacity to reenter cell cycle and might thus convert unrepaired DNA lesions into mutations, a prerequisite for malignant transformation. Here we report that quiescent primary human B lymphocytes down-regulate NER at the global genome level while maintaining proficient repair of constitutively expressed genes. Quiescent B cells exposed to an environment that causes both DNA damage and proliferation accumulate point mutations in silent and inducible genes crucial for cell replication and differentiation, such as BCL6 and Cyclin D2. Similar to differentiated cells, NER attenuation in quiescent cells is associated with incomplete phosphorylation of the ubiquitin activating enzyme Ube1, which is required for proficient NER. Our data establish a mechanistic link between NER attenuation during quiescence and cell mutagenesis and also support the concept that oncogenic events targeting cell cycle- or activation-induced genes might initiate genomic instability and lymphomagenesis.

scholarly journals Mechanism of DNA Lesion Homing and Recognition by the Uvr Nucleotide Excision Repair System

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Seung-Joo Lee ◽  
Rou-Jia Sung ◽  
Gregory L. Verdine
Keyword(s):  
Dna Repair ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Lesions ◽  
Repair System ◽  
Genome Maintenance ◽  
Dna Lesion ◽  
Nucleotide Excision ◽  
Biochemical Studies ◽  
Lesion Recognition

Nucleotide excision repair (NER) is an essential DNA repair system distinguished from other such systems by its extraordinary versatility. NER removes a wide variety of structurally dissimilar lesions having only their bulkiness in common. NER can also repair several less bulky nucleobase lesions, such as 8-oxoguanine. Thus, how a single DNA repair system distinguishes such a diverse array of structurally divergent lesions from undamaged DNA has been one of the great unsolved mysteries in the field of genome maintenance. Here we employ a synthetic crystallography approach to obtain crystal structures of the pivotal NER enzyme UvrB in complex with duplex DNA, trapped at the stage of lesion-recognition. These structures coupled with biochemical studies suggest that UvrB integrates the ATPase-dependent helicase/translocase and lesion-recognition activities. Our work also conclusively establishes the identity of the lesion-containing strand and provides a compelling insight to how UvrB recognizes a diverse array of DNA lesions.

scholarly journals Role of Nucleotide Excision Repair in Cisplatin Resistance

2020 ◽  
Vol 21 (23) ◽  
pp. 9248
Author(s):  
Mingrui Duan ◽  
Jenna Ulibarri ◽  
Ke Jian Liu ◽  
Peng Mao
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Resistance Mechanism ◽  
Repair System ◽  
Repair Synthesis ◽  
Wide Range ◽  
Nucleotide Excision ◽  
Damage Mapping

Cisplatin is a chemotherapeutic drug used for the treatment of a number of cancers. The efficacy of cisplatin relies on its binding to DNA and the induction of cytotoxic DNA damage to kill cancer cells. Cisplatin-based therapy is best known for curing testicular cancer; however, treatment of other solid tumors with cisplatin has not been as successful. Pre-clinical and clinical studies have revealed nucleotide excision repair (NER) as a major resistance mechanism against cisplatin in tumor cells. NER is a versatile DNA repair system targeting a wide range of helix-distorting DNA damage. The NER pathway consists of multiple steps, including damage recognition, pre-incision complex assembly, dual incision, and repair synthesis. NER proteins can recognize cisplatin-induced DNA damage and remove the damage from the genome, thereby neutralizing the cytotoxicity of cisplatin and causing drug resistance. Here, we review the molecular mechanism by which NER repairs cisplatin damage, focusing on the recent development of genome-wide cisplatin damage mapping methods. We also discuss how the expression and somatic mutations of key NER genes affect the response of cancer cells to cisplatin. Finally, small molecules targeting NER factors provide important tools to manipulate NER capacity in cancer cells. The status of research on these inhibitors and their implications in cancer treatment will be discussed.

scholarly journals Structural basis of TFIIH activation for nucleotide excision repair

2019 ◽  
Author(s):  
Goran Kokic ◽  
Aleksandar Chernev ◽  
Dimitry Tegunov ◽  
Christian Dienemann ◽  
Henning Urlaub ◽  
...  
Keyword(s):  
Dna Repair ◽  
Transcription Factor ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Lesions ◽  
Structural Basis ◽  
Disease Mutations ◽  
Mechanistic Analysis ◽  
Nucleotide Excision ◽  
Dna Complex

AbstractGenomes are constantly threatened by DNA damage, but cells can remove a large variety of DNA lesions by nucleotide excision repair (NER)1. Mutations in NER factors compromise cellular fitness and cause human diseases such as Xeroderma pigmentosum (XP), Cockayne syndrome and trichothiodystrophy2,3. The NER machinery is built around the multisubunit transcription factor IIH (TFIIH), which opens the DNA repair bubble, scans for the lesion, and coordinates excision of the damaged DNA single strand fragment1,4. TFIIH consists of a kinase module and a core module that contains the ATPases XPB and XPD5. Here we prepare recombinant human TFIIH and show that XPB and XPD are stimulated by the additional NER factors XPA and XPG, respectively. We then determine the cryo-electron microscopy structure of the human core TFIIH-XPA-DNA complex at 3.6 Å resolution. The structure represents the lesion-scanning intermediate on the NER pathway and rationalizes the distinct phenotypes of disease mutations. It reveals that XPB and XPD bind double- and single-stranded DNA, respectively, consistent with their translocase and helicase activities. XPA forms a bridge between XPB and XPD, and retains the DNA at the 5’-edge of the repair bubble. Biochemical data and comparisons with prior structures6,7 explain how XPA and XPG can switch TFIIH from a transcription factor to a DNA repair factor. During transcription, the kinase module inhibits the repair helicase XPD8. For DNA repair, XPA dramatically rearranges the core TFIIH structure, which reorients the ATPases, releases the kinase module and displaces a ‘plug’ element from the DNA-binding pore in XPD. This enables XPD to move by ~80 Å, engage with DNA, and scan for the lesion in a XPG-stimulated manner. Our results provide the basis for a detailed mechanistic analysis of the NER mechanism.

scholarly journals Histone H4 H75E mutation attenuates global genomic and Rad26-independent transcription-coupled nucleotide excision repair

2019 ◽  
Vol 47 (14) ◽  
pp. 7392-7401 ◽  
Author(s):  
Kathiresan Selvam ◽  
Sheikh Arafatur Rahman ◽  
Shisheng Li
Keyword(s):  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Histone H3 ◽  
Chromatin Accessibility ◽  
Dna Lesions ◽  
Histone H4 ◽  
Uv Sensitivity ◽  
Nucleotide Excision ◽  
Histone Octamers ◽  
Dna Silencing

Abstract Nucleotide excision repair (NER) consists of global genomic NER (GG-NER) and transcription coupled NER (TC-NER) subpathways. In eukaryotic cells, genomic DNA is wrapped around histone octamers (an H3–H4 tetramer and two H2A–H2B dimers) to form nucleosomes, which are well known to profoundly inhibit the access of NER proteins. Through unbiased screening of histone H4 residues in the nucleosomal LRS (loss of ribosomal DNA-silencing) domain, we identified 24 mutations that enhance or decrease UV sensitivity of Saccharomyces cerevisiae cells. The histone H4 H75E mutation, which is largely embedded in the nucleosome and interacts with histone H2B, significantly attenuates GG-NER and Rad26-independent TC-NER but does not affect TC-NER in the presence of Rad26. All the other histone H4 mutations, except for T73F and T73Y that mildly attenuate GG-NER, do not substantially affect GG-NER or TC-NER. The attenuation of GG-NER and Rad26-independent TC-NER by the H4H75E mutation is not due to decreased chromatin accessibility, impaired methylation of histone H3 K79 that is at the center of the LRS domain, or lowered expression of NER proteins. Instead, the attenuation is at least in part due to impaired recruitment of Rad4, the key lesion recognition and verification protein, to chromatin following induction of DNA lesions.

scholarly journals Photoprotective Role of Photolyase-Interacting RAD23 and Its Pleiotropic Effect on the Insect-Pathogenic Fungus Beauveria bassiana

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Ding-Yi Wang ◽  
Ya-Ni Mou ◽  
Sen-Miao Tong ◽  
Sheng-Hua Ying ◽  
Ming-Guang Feng
Keyword(s):  
Visible Light ◽  
Nucleotide Excision Repair ◽  
Radial Growth ◽  
Essential Role ◽  
Excision Repair ◽  
Pathogenic Fungus ◽  
Dna Lesions ◽  
Content Type ◽  
Multiple Stress ◽  
Nucleotide Excision

ABSTRACT RAD23 can repair yeast DNA lesions through nucleotide excision repair (NER), a mechanism that is dependent on proteasome activity and ubiquitin chains but different from photolyase-depending photorepair of UV-induced DNA damages. However, this accessory NER protein remains functionally unknown in filamentous fungi. In this study, orthologous RAD23 in Beauveria bassiana, an insect-pathogenic fungus that is a main source of fungal insecticides, was found to interact with the photolyase PHR2, enabling repair of DNA lesions by degradation of UVB-induced cytotoxic (6-4)-pyrimidine-pyrimidine photoproducts under visible light, and it hence plays an essential role in the photoreactivation of UVB-inactivated conidia but no role in reactivation of such conidia through NER in dark conditions. Fluorescence-labeled RAD23 was shown to normally localize in the cytoplasm, to migrate to vacuoles in the absence of carbon, nitrogen, or both, and to enter nuclei under various stresses, which include UVB, a harmful wavelength of sunlight. Deletion of the rad23 gene resulted in an 84% decrease in conidial UVB resistance, a 95% reduction in photoreactivation rate of UVB-inactivated conidia, and a drastic repression of phr2. A yeast two-hybrid assay revealed a positive RAD23-PHR2 interaction. Overexpression of phr2 in the Δrad23 mutant largely mitigated the severe defect of the Δrad23 mutant in photoreactivation. Also, the deletion mutant was severely compromised in radial growth, conidiation, conidial quality, virulence, multiple stress tolerance, and transcriptional expression of many phenotype-related genes. These findings unveil not only the pleiotropic effects of RAD23 in B. bassiana but also a novel RAD23-PHR2 interaction that is essential for the photoprotection of filamentous fungal cells from UVB damage. IMPORTANCE RAD23 is able to repair yeast DNA lesions through nucleotide excision in full darkness, a mechanism distinct from photolyase-dependent photorepair of UV-induced DNA damage but functionally unknown in filamentous fungi. Our study unveils that the RAD23 ortholog in a filamentous fungal insect pathogen varies in subcellular localization according to external cues, interacts with a photolyase required for photorepair of cytotoxic (6-4)-pyrimidine-pyrimidine photoproducts in UV-induced DNA lesions, and plays an essential role in conidial UVB resistance and reactivation of UVB-inactivated conidia under visible light rather than in the dark, as required for nucleotide excision repair. Loss-of-function mutations of RAD23 exert pleiotropic effects on radial growth, aerial conidiation, multiple stress responses, virulence, virulence-related cellular events, and phenotype-related gene expression. These findings highlight a novel mechanism underlying the photoreactivation of UVB-impaired fungal cells by RAD23 interacting with the photolyase, as well as its essentiality for filamentous fungal life.

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