scholarly journals The small DdrR protein directly interacts with the UmuDAb regulator to inhibit the mutagenic DNA damage response in Acinetobacter baumannii

2020 ◽  
Author(s):  
Anja Pavlin ◽  
Gregor Bajc ◽  
Nadine Fornelos ◽  
Douglas F. Browning ◽  
Matej Butala
Keyword(s):  
Acinetobacter Baumannii ◽  
Dna Polymerase ◽  
Molecular Mechanisms ◽  
Stable Complex ◽  
Healthcare Settings ◽  
Target Dna ◽  
Dna Polymerase V ◽  
Repressor Complex ◽  
Damage Response ◽  
Operator Binding

AbstractAcinetobacter baumannii poses a great threat in healthcare settings worldwide with clinical isolates revealing an ever evolving multidrug-resistance. Here, we report the molecular mechanisms governing the tight repression of the error-prone DNA polymerase umuDC genes in this important bacterial human pathogen. We demonstrate that the small DdrR protein directly interacts with the UmuDAb transcription repressor, which possesses some similarities to LexA proteins from other bacteria, to increase the repressor’s affinity for target sequences in the umuDC operon. These data reveal that DdrR forms a stable complex with free UmuDAb but is released upon association of this repressor complex with target DNA. We show that DdrR also interacts with UmuD, a component of DNA polymerase V and that DdrR enhances the operator binding of LexA repressors from Clostridium difficile, Bacillus thuringiensis and Staphylococcus aureus. Our results suggest that proteins that assist the action of LexA-like transcription factors may be common to many, if not all, bacteria that mount the SOS response.

scholarly journals Role of Acinetobacter baumannii UmuD Homologs in Antibiotic Resistance Acquired through DNA Damage-Induced Mutagenesis

2013 ◽  
Vol 58 (3) ◽  
pp. 1771-1773 ◽  
Author(s):  
Jesús Aranda ◽  
Mario López ◽  
Enoy Leiva ◽  
Andrés Magán ◽  
Ben Adler ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Acinetobacter Baumannii ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Wild Type ◽  
Content Type ◽  
Dna Polymerase V ◽  
Induced Mutagenesis ◽  
Related Survival

ABSTRACTThe role ofAcinetobacter baumanniiATCC 17978 UmuDC homologs A1S_0636-A1S_0637, A1S_1174-A1S_1173, and A1S_1389 (UmuDAb) in antibiotic resistance acquired through UV-induced mutagenesis was evaluated. Neither the growth rate nor the UV-related survival of any of the three mutants was significantly different from that of the wild-type parental strain. However, all mutants, and especially theumuDAbmutant, were less able to acquire resistance to rifampin and streptomycin through the activities of their error-prone DNA polymerases. Furthermore, in theA. baumanniimutant defective in theumuDAbgene, the spectrum of mutations included a dramatic reduction in the frequency of transition mutations, the mutagenic signature of the DNA polymerase V encoded byumuDC.

scholarly journals The SOS Error-Prone DNA Polymerase V Mutasome and β-Sliding Clamp Acting in Concert on Undamaged DNA and during Translesion Synthesis

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1083
Author(s):  
Adhirath Sikand ◽  
Malgorzata Jaszczur ◽  
Linda B. Bloom ◽  
Roger Woodgate ◽  
Michael M. Cox ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Pathogenic Bacteria ◽  
Fold Increase ◽  
Translesion Dna Synthesis ◽  
Sliding Clamp ◽  
Pol V ◽  
Dna Polymerase V ◽  
Acting In Concert

In the mid 1970s, Miroslav Radman and Evelyn Witkin proposed that Escherichia coli must encode a specialized error-prone DNA polymerase (pol) to account for the 100-fold increase in mutations accompanying induction of the SOS regulon. By the late 1980s, genetic studies showed that SOS mutagenesis required the presence of two “UV mutagenesis” genes, umuC and umuD, along with recA. Guided by the genetics, decades of biochemical studies have defined the predicted error-prone DNA polymerase as an activated complex of these three gene products, assembled as a mutasome, pol V Mut = UmuD’2C-RecA-ATP. Here, we explore the role of the β-sliding processivity clamp on the efficiency of pol V Mut-catalyzed DNA synthesis on undamaged DNA and during translesion DNA synthesis (TLS). Primer elongation efficiencies and TLS were strongly enhanced in the presence of β. The results suggest that β may have two stabilizing roles: its canonical role in tethering the pol at a primer-3’-terminus, and a possible second role in inhibiting pol V Mut’s ATPase to reduce the rate of mutasome-DNA dissociation. The identification of umuC, umuD, and recA homologs in numerous strains of pathogenic bacteria and plasmids will ensure the long and productive continuation of the genetic and biochemical journey initiated by Radman and Witkin.

scholarly journals Genome-wide association study suggests that variation at the RCOR1 locus is associated with tinnitus in UK Biobank

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena R. R. Wells ◽  
Fatin N. Zainul Abidin ◽  
Maxim B. Freidin ◽  
Frances M. K. Williams ◽  
Sally J. Dawson
Keyword(s):  
Association Study ◽  
Molecular Mechanisms ◽  
Genome Wide Association Study ◽  
Genome Wide Association ◽  
Uk Biobank ◽  
Significance Threshold ◽  
Genome Wide ◽  
Final Sample ◽  
Close Proximity ◽  
Repressor Complex

AbstractTinnitus is a prevalent condition in which perception of sound occurs without an external stimulus. It is often associated with pre-existing hearing loss or noise-induced damage to the auditory system. In some individuals it occurs frequently or even continuously and leads to considerable distress and difficulty sleeping. There is little knowledge of the molecular mechanisms involved in tinnitus which has hindered the development of treatments. Evidence suggests that tinnitus has a heritable component although previous genetic studies have not established specific risk factors. From a total of 172,608 UK Biobank participants who answered questions on tinnitus we performed a case–control genome-wide association study for self-reported tinnitus. Final sample size used in association analysis was N = 91,424. Three variants in close proximity to the RCOR1 gene reached genome wide significance: rs4906228 (p = 1.7E−08), rs4900545 (p = 1.8E−08) and 14:103042287_CT_C (p = 3.50E−08). RCOR1 encodes REST Corepressor 1, a component of a co-repressor complex involved in repressing neuronal gene expression in non-neuronal cells. Eleven other independent genetic loci reached a suggestive significance threshold of p < 1E−06.

scholarly journals Single-stranded DNA-binding Protein Recruits DNA Polymerase V to Primer Termini on RecA-coated DNA

2008 ◽  
Vol 283 (13) ◽  
pp. 8274-8282 ◽  
Author(s):  
Gali Arad ◽  
Ayal Hendel ◽  
Claus Urbanke ◽  
Ute Curth ◽  
Zvi Livneh
Keyword(s):  
Dna Binding ◽  
Dna Polymerase ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Single Stranded Dna ◽  
Dna Polymerase V

Mitochondrial Disorders of DNA Polymerase γ Dysfunction: From Anatomic to Molecular Pathology Diagnosis

2011 ◽  
Vol 135 (7) ◽  
pp. 925-934
Author(s):  
Linsheng Zhang ◽  
Sherine S. L. Chan ◽  
Daynna J. Wolff
Keyword(s):  
Dna Polymerase ◽  
Molecular Mechanisms ◽  
Clinical Laboratory ◽  
Laboratory Diagnosis ◽  
Molecular Study ◽  
Mitochondrial Disorders ◽  
Definitive Diagnosis ◽  
Inherited Disorders ◽  
Cooperative Effort ◽  
Dna Polymerase Γ

Abstract Context.—Primary mitochondrial dysfunction is one of the most common causes of inherited disorders predominantly involving the neuromuscular system. Advances in the molecular study of mitochondrial DNA have changed our vision and our approach to primary mitochondrial disorders. Many of the mitochondrial disorders are caused by mutations in nuclear genes and are inherited in an autosomal recessive pattern. Among the autosomal inherited mitochondrial disorders, those related to DNA polymerase γ dysfunction are the most common and the best studied. Understanding the molecular mechanisms and being familiar with the recent advances in laboratory diagnosis of this group of mitochondrial disorders are essential for pathologists to interpret abnormal histopathology and laboratory results and to suggest further studies for a definitive diagnosis. Objectives.—To help pathologists better understand the common clinical syndromes originating from mutations in DNA polymerase γ and its associated proteins and use the stepwise approach of clinical, laboratory, and pathologic diagnosis of these syndromes. Data Sources.—Review of pertinent published literature and relevant Internet databases. Conclusions.—Mitochondrial disorders are now better recognized with the development of molecular tests for clinical diagnosis. A cooperative effort among primary physicians, diagnostic pathologists, geneticists, and molecular biologists with expertise in mitochondrial disorders is required to reach a definitive diagnosis.

scholarly journals Molecular mechanisms associated with clustered lesion-induced impairment of 8-oxoG recognition by the human glycosylase OGG1

2021 ◽  
Author(s):  
Tao Jiang ◽  
Antonio MONARI ◽  
Elise Dumont ◽  
Emmanuelle Bignon
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Excision Repair ◽  
Structural Features ◽  
Repair Pathway ◽  
Dna Lesion ◽  
Damage Response ◽  
Base Excision ◽  
Structural Signature ◽  
Dynamics Simulations

The 8-oxo-7,8-dihydroguanine, referred to as 8-oxoG, is a highly mutagenic DNA lesion that can provoke the appearance of mismatches if it escapes the DNA Damage Response. The specific recognition of its structural signature by the hOGG1 glycosylase is the first step along the Base Excision Repair pathway, that ensures the integrity of the genome by preventing the emergence of mutations. 8-oxoG formation, structural features and repair have been the matter of extensive research and more recently this active field of research expended to the more complicated case of 8-oxoG within clustered lesions. Indeed, the presence of a second lesion within 1 or 2 helix turns can dramatically impact the repair yields of 8-oxoG by glycosylases. In this work, we use mu-range molecular dynamics simulations and machine learning-based post-analysis to explore the molecular mechanisms associated with the recognition of 8-oxoG by hOGG1 when embedded in a multiple lesions site with a mismatch in 5' or 3'. We delineate the stiffening of the DNA-protein interactions upon the presence of the mismatches, and rationalize the much lower repair yields reported with a 5' mismatch by describing the perturbation of 8-oxoG structural features upon addition of an adjacent lesion.

scholarly journals Efficient target cleavage by Type V Cas12a effector programmed with split CRISPR RNA

2020 ◽  
Author(s):  
Regina Tkach ◽  
Natalia Nikitchina ◽  
Nikita Shebanov ◽  
Vladimir Mekler ◽  
Egor Ulashchik ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dna Cleavage ◽  
Target Recognition ◽  
Human Cells ◽  
Stable Complex ◽  
Slight Effect ◽  
Target Dna ◽  
Type V

ABSTRACTCRISPR RNAs (crRNAs) directing target DNA cleavage by type V-A Cas12a nucleases consist of repeat-derived 5’-scaffold moiety and 3’-spacer moiety. We demonstrate that removal of most of the 20-nucleotide scaffold has only a slight effect on in vitro target DNA cleavage by Cas12a ortholog from Acidaminococcus sp (AsCas12a). In fact, residual cleavage was observed even in the presence of a 20-nucleotide crRNA spacer part only, while crRNAs split into two individual moieties (scaffold and spacer RNAs) catalyzed highly specific and efficient cleavage of target DNA. Our data also indicate that AsCas12a combined with split crRNA forms a stable complex with the target. These observations were also confirmed in lysates of human cells expressing AsCas12a. The ability of the AsCas12a nuclease to be programmed with split crRNAs opens new lines of inquiry into the mechanisms of target recognition and cleavage and will further facilitate genome editing techniques based on Cas12a nucleases.

scholarly journals Molecular Mechanisms of Specific Cellular DNA Damage Response and Repair Induced by the Mixed Radiation Field During Boron Neutron Capture Therapy

2021 ◽  
Vol 11 ◽  
Author(s):  
Kamila Maliszewska-Olejniczak ◽  
Damian Kaniowski ◽  
Martyna Araszkiewicz ◽  
Katarzyna Tymińska ◽  
Agnieszka Korgul
Keyword(s):  
Dna Damage ◽  
Radiation Field ◽  
Dna Damage Response ◽  
Boron Neutron Capture Therapy ◽  
Neutron Capture ◽  
Molecular Mechanisms ◽  
Neutron Capture Therapy ◽  
Boron Neutron Capture ◽  
Damage Response ◽  
Mixed Radiation Field

The impact of a mixed neutron-gamma beam on the activation of DNA damage response (DDR) proteins and non-coding RNAs (ncRNAs) is poorly understood. Ionizing radiation is characterized by its biological effectiveness and is related to linear energy transfer (LET). Neutron-gamma mixed beam used in boron neutron capture therapy (BNCT) can induce another type of DNA damage such as clustered DNA or multiple damaged sites, as indicated for high LET particles, such as alpha particles, carbon ions, and protons. We speculate that after exposure to a mixed radiation field, the repair capacity might reduce, leading to unrepaired complex DNA damage for a long period and may promote genome instability and cell death. This review will focus on the poorly studied impact of neutron-gamma mixed beams with an emphasis on DNA damage and molecular mechanisms of repair. In case of BNCT, it is not clear which repair pathway is involved, and recent experimental work will be presented. Further understanding of BNCT-induced DDR mechanisms may lead to improved therapeutic efficiency against different tumors.

UmuDC Lesion Bypass DNA Polymerase V

2020 ◽  
Author(s):  
Penny J. Beuning ◽  
Hannah R. Stern ◽  
Ryan J. Dilworth
Keyword(s):  
Dna Polymerase ◽  
Lesion Bypass ◽  
Dna Polymerase V

scholarly journals High Fidelity Deep Sequencing Reveals No Effect of ATM, ATR, and DNA-PK Cellular DNA Damage Response Pathways on Adenovirus Mutation Rate

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 938 ◽  
Author(s):  
Risso-Ballester ◽  
Sanjuán
Keyword(s):  
Dna Damage ◽  
Protein Kinase ◽  
Dna Damage Response ◽  
Deep Sequencing ◽  
Molecular Mechanisms ◽  
Spontaneous Mutation ◽  
High Fidelity ◽  
Dna Viruses ◽  
Damage Response ◽  
Cellular Dna

Most DNA viruses exhibit relatively low rates of spontaneous mutation. However, the molecular mechanisms underlying DNA virus genetic stability remain unclear. In principle, mutation rates should not depend solely on polymerase fidelity, but also on factors such as DNA damage and repair efficiency. Most eukaryotic DNA viruses interact with the cellular DNA damage response (DDR), but the role of DDR pathways in preventing mutations in the virus has not been tested empirically. To address this goal, we serially transferred human adenovirus type 5 in cells in which the telangiectasia-mutated PI3K-related protein kinase (ATM), the ATM/Rad3-related (ATR) kinase, and the DNA-dependent protein kinase (DNA-PK) were chemically inactivated, as well as in control cells displaying normal DDR pathway functioning. High-fidelity deep sequencing of these viral populations revealed mutation frequencies in the order of one-millionth, with no detectable effect of the inactivation of DDR mediators ATM, ATR, and DNA-PK on adenovirus sequence variability. This suggests that these DDR pathways do not play a major role in determining adenovirus genetic diversity.

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