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Nanomaterials (Basel, Switzerland) Dec 2022Research on nano- and micro-plastic particles (NMPPs) suggests their potential threat to human health. Some studies have even suggested genotoxic effects of NMPP...
Research on nano- and micro-plastic particles (NMPPs) suggests their potential threat to human health. Some studies have even suggested genotoxic effects of NMPP exposure, such as micronuclei (MN) formation, while others found the opposite. To clarify the ability of NMPP to induce MN formation, we used non-malignant HaCaT keratinocytes and exposed these to a variety of polystyrene (PS) and poly methyl methacrylate (PMMA) particle types at different concentrations and three different sizes. Investigations were performed following acute (one day) and chronic exposure (five weeks) against cytotoxic (amino-modified NMPPs) and genotoxic (methyl methanesulfonate, MMS) positive controls. An optimized high-content imaging workflow was established strictly according to OECD guidelines for analysis. Algorithm-based object segmentation and MN identification led to computer-driven, unsupervised quantitative image analysis results on MN frequencies among the different conditions and thousands of cells per condition. This could only be realized using accutase, allowing for partial cell detachment for optimal identification of bi-nucleated cells. Cytotoxic amino-modified particles were not genotoxic; MMS was both. During acute and long-term studies, PS and PMMA particles were neither toxic nor increased MN formation, except for 1000 nm PS particles at the highest concentration of unphysiological 100 µg/mL. Interestingly, ROS formation was significantly decreased in this condition. Hence, most non-charged polymer particles were neither toxic nor genotoxic, while aminated particles were toxic but not genotoxic. Altogether, we present an optimized quantitative imaging workflow applied to a timely research question in environmental toxicity.
PubMed: 36558315
DOI: 10.3390/nano12244463 -
Nucleic Acids Research Dec 2022UV-DDB is a DNA damage recognition protein recently discovered to participate in the removal of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoG) by stimulating multiple...
UV-DDB is a DNA damage recognition protein recently discovered to participate in the removal of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxoG) by stimulating multiple steps of base excision repair (BER). In this study, we examined whether UV-DDB has a wider role in BER besides oxidized bases and found it has specificity for two known DNA substrates of alkyladenine glycosylase (AAG)/N-methylpurine DNA glycosylase (MPG): 1, N6-ethenoadenine (ϵA) and hypoxanthine. Gel mobility shift assays show that UV-DDB recognizes these two lesions 4-5 times better than non-damaged DNA. Biochemical studies indicated that UV-DDB stimulated AAG activity on both substrates by 4- to 5-fold. Native gels indicated UV-DDB forms a transient complex with AAG to help facilitate release of AAG from the abasic site product. Single molecule experiments confirmed the interaction and showed that UV-DDB can act to displace AAG from abasic sites. Cells when treated with methyl methanesulfonate resulted in foci containing AAG and UV-DDB that developed over the course of several hours after treatment. While colocalization did not reach 100%, foci containing AAG and UV-DDB reached a maximum at three hours post treatment. Together these data indicate that UV-DDB plays an important role in facilitating the repair of AAG substrates.
Topics: DNA Glycosylases; DNA Damage; DNA Repair; DNA
PubMed: 36511855
DOI: 10.1093/nar/gkac1145 -
BMC Plant Biology Dec 2022MicroRNAs (miRNAs) and other epigenetic modifications play fundamental roles in all eukaryotic biological processes. DNA damage repair is a key process for maintaining...
BACKGROUND
MicroRNAs (miRNAs) and other epigenetic modifications play fundamental roles in all eukaryotic biological processes. DNA damage repair is a key process for maintaining the genomic integrity of different organisms exposed to diverse stresses. However, the reaction of miRNAs in the DNA damage repair process is unclear.
RESULTS
In this study, we found that the simultaneous mutation of zinc finger DNA 3'-phosphoesterase (ZDP) and AP endonuclease 2 (APE2), two genes that play overlapping roles in active DNA demethylation and base excision repair (BER), led to genome-wide alteration of miRNAs. The transcripts of newly transcribed miRNA-encoding genes (MIRs) decreased significantly in zdp/ape2, indicating that the mutation of ZDP and APE2 affected the accumulation of miRNAs at the transcriptional level. In addition, the introduction of base damage with the DNA-alkylating reagent methyl methanesulfonate (MMS) accelerated the reduction of miRNAs in zdp/ape2. Further mutation of FORMAMIDOPYRIMIDINE DNA GLYCOSYLASE (FPG), a bifunctional DNA glycosylase/lyase, rescued the accumulation of miRNAs in zdp/ape2, suggesting that the accumulation of DNA damage repair intermediates induced the transcriptional repression of miRNAs.
CONCLUSIONS
Our investigation indicates that the accumulation of DNA damage repair intermediates inhibit miRNAs accumulation by inhibiting MIR transcriptions.
Topics: Arabidopsis; DNA Damage; DNA Repair; Transcription, Genetic; MicroRNAs; Endonucleases; Arabidopsis Proteins
PubMed: 36503409
DOI: 10.1186/s12870-022-03951-9 -
The New Phytologist Mar 2023The endonuclease methyl methanesulfonate and UV-sensitive protein 81 (MUS81) has been reported to participate in DNA repair during mitosis and meiosis. However, the...
The endonuclease methyl methanesulfonate and UV-sensitive protein 81 (MUS81) has been reported to participate in DNA repair during mitosis and meiosis. However, the exact meiotic function of MUS81 in rice remains unclear. Here, we use a combination of physiological, cytological, and genetic approaches to provide evidence that MUS81 functions in atypical recombination intermediate resolution rather than crossover designation in rice. Cytological and genetic analysis revealed that the total chiasma numbers in mus81 mutants were indistinguishable from wild-type. The numbers of HEI10 foci (the sites of interference-sensitive crossovers) in mus81 were also similar to that of wild-type. Moreover, disruption of MUS81 in msh5 or msh4 msh5 background did not further decrease chiasmata frequency, suggesting that rice MUS81 did not function in crossover designation. Mutation of FANCM and ZEP1 could enhance recombination frequency. Unexpectedly, chromosome fragments and bridges were frequently observed in mus81 zep1 and mus81 fancm, illustrating that MUS81 may resolve atypical recombination intermediates. Taken together, our data suggest that MUS81 contributes little to crossover designation but plays a crucial role in the resolution of atypical meiotic intermediates by working together with other anti-crossover factors.
Topics: Crossing Over, Genetic; DNA-Binding Proteins; Oryza; Meiosis; Endonucleases
PubMed: 36495065
DOI: 10.1111/nph.18668 -
Plant Physiology Mar 2023Changes in plant auxin levels can be perceived and converted into cellular responses by auxin signal transduction. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins are...
Changes in plant auxin levels can be perceived and converted into cellular responses by auxin signal transduction. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins are auxin transcriptional inhibitors that play important roles in regulating auxin signal transduction. The stability of Aux/IAA proteins is important for transcription initiation and downstream auxin-related gene expression. Here, we report that the Aux/IAA protein IAA17 interacts with the small ubiquitin-related modifier (SUMO) E3 ligase METHYL METHANESULFONATE-SENSITIVE 21 (AtMMS21) in Arabidopsis (Arabidopsis thaliana). AtMMS21 regulated the SUMOylation of IAA17 at the K41 site. Notably, root length was suppressed in plants overexpressing IAA17, whereas the roots of K41-mutated IAA17 transgenic plants were not significantly different from wild-type roots. Biochemical data indicated that K41-mutated IAA17 or IAA17 in the AtMMS21 knockout mutant was more likely to be degraded compared with nonmutated IAA17 in wild-type plants. In conclusion, our data revealed a role for SUMOylation in the maintenance of IAA17 protein stability, which contributes to improving our understanding of the mechanisms of auxin signaling.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Indoleacetic Acids; Plant Roots; Signal Transduction; Sumoylation; Ubiquitin; Ubiquitin-Protein Ligases
PubMed: 36464768
DOI: 10.1093/plphys/kiac553 -
IUCrData Oct 2021The title mol-ecular salt, CHNOS·CHOS, consists of a cationic sulfonated pyridine -oxide moiety and a methane-sulfonate anion. An N-O bond length of 1.4004 (15) Å...
The title mol-ecular salt, CHNOS·CHOS, consists of a cationic sulfonated pyridine -oxide moiety and a methane-sulfonate anion. An N-O bond length of 1.4004 (15) Å is observed in the cation. In the crystal, weak C-H⋯O inter-actions link the components into a three-dimensional network.
PubMed: 36340987
DOI: 10.1107/S2414314621010269 -
Toxicology in Vitro : An International... Feb 2023Exopolysaccharide isolated from Lactobacillus salivarius (new genus name Ligilactobacillus) KC27L strain (EPS) exhibits antioxidant properties with...
Exopolysaccharide isolated from Lactobacillus salivarius (new genus name Ligilactobacillus) KC27L strain (EPS) exhibits antioxidant properties with 1,1-diphenyl-2-picrylhydrazase (DPPH) radical and superoxide anion radical (O) scavenging effect and iron ion (Fe) chelating activity. This study aimed to investigate the in vitro genotoxic effects of EPS alone (12.50, 25.00, 50.00, and 100.00 μg/mL) and its antigenotoxic activity against DNA damage induced by mitomycin-C (MMC; 0.20 μg/mL), methyl methanesulfonate (MMS; 5.00 μg/mL), and hydrogen peroxide (HO; 100 μM). For this purpose, chromosome aberration (CA), sister chromatid exchange (SCE), micronucleus (MN), and comet assays were performed in human peripheral lymphocytes. In addition, the structure of EPS was investigated in the scanning electron microscope (SEM). EPS alone did not cause a significant genotoxic effect in CA, SCE, MN, and comet tests. EPS significantly decreased the frequency of CA, SCE, and MN induced by MMC and MMS. EPS also significantly reduced DNA damage induced by HO. This study showed that the EPS alone has no genotoxic risk at these concentrations and shows antigenotoxic activity against MMC, MMS, and HO. Consequently, EPS was found to exhibit chemopreventive activity against genotoxic agents. This effect is believed to be due to the antioxidant properties of EPS.
Topics: Humans; Micronucleus Tests; Ligilactobacillus salivarius; Antioxidants; Hydrogen Peroxide; Sister Chromatid Exchange; DNA Damage; Chromosome Aberrations; Lymphocytes; Mitomycin
PubMed: 36336210
DOI: 10.1016/j.tiv.2022.105507 -
Plant Physiology Jan 2023DNA damage response (DDR) in eukaryotes is essential for the maintenance of genome integrity in challenging environments. The regulatory mechanisms of DDR have been...
DNA damage response (DDR) in eukaryotes is essential for the maintenance of genome integrity in challenging environments. The regulatory mechanisms of DDR have been well-established in yeast and humans. However, increasing evidence supports the idea that plants seem to employ different signaling pathways that remain largely unknown. Here, we report the role of MODIFIER OF SNC1, 4-ASSOCIATED COMPLEX SUBUNIT 5A (MAC5A) in DDR in Arabidopsis (Arabidopsis thaliana). Lack of MAC5A in mac5a mutants causes hypersensitive phenotypes to methyl methanesulfonate (MMS), a DNA damage inducer. Consistent with this observation, MAC5A can regulate alternative splicing of DDR genes to maintain the proper response to genotoxic stress. Interestingly, MAC5A interacts with the 26S proteasome (26SP) and is required for its proteasome activity. MAC core subunits are also involved in MMS-induced DDR. Moreover, we find that MAC5A, the MAC core subunits, and 26SP may act collaboratively to mediate high-boron-induced growth repression through DDR. Collectively, our findings uncover the crucial role of MAC in MMS-induced DDR in orchestrating growth and stress adaptation in plants.
Topics: Arabidopsis; Arabidopsis Proteins; DNA Damage; Proteasome Endopeptidase Complex; R-SNARE Proteins; RNA-Binding Proteins
PubMed: 36331331
DOI: 10.1093/plphys/kiac510 -
Frontiers in Genetics 2022Methyl methanesulfonate-sensitivity protein 22-like (MMS22L) is crucial in protecting genome integrity during DNA replication by preventing DNA damage and maintaining...
Methyl methanesulfonate-sensitivity protein 22-like (MMS22L) is crucial in protecting genome integrity during DNA replication by preventing DNA damage and maintaining efficient homologous recombination. However, the role of MMS22L in human cancers remains unclear. Here, we reported the landscape of MMS22L using multi-omics data and identified the relationship between the MMS22L status and pan-cancer prognosis. In addition, the correlation of MMS22L mRNA expression levels with tumor mutational burden, microsatellite instability, homologous recombination deficiency, and loss of heterozygosity in pan-cancer was also described in this study. Furthermore, this study was the first to characterize the relationship between mRNA expression of MMS22L and immune cell infiltration in the tumor microenvironment in human cancer. Concurrently, this study explored the crucial role of MMS22L in different immunotherapy cohorts through current immunotherapy experiments. Eventually, we investigated the role of MMS22L in hepatocellular carcinoma (HCC). The results demonstrated that MMS22L is widely expressed in multiple HCC cell lines, and our results emphasized that MMS22L was involved in HCC progression and affects the prognosis of patients with HCC through multiple independent validation cohorts. Collectively, our findings reveal the essential role of MMS22L as a tumor-regulating gene in human cancers while further emphasizing its feasibility as a novel molecular marker in HCC. These findings provide an essential reference for the study of MMS22L in tumors.
PubMed: 36276962
DOI: 10.3389/fgene.2022.1025970 -
Molecules (Basel, Switzerland) Oct 2022Ionic liquids (ILs) have emerged as active pharmaceutical ingredients because of their excellent antibacterial and biological activities. Herein, we used the...
Ionic liquids (ILs) have emerged as active pharmaceutical ingredients because of their excellent antibacterial and biological activities. Herein, we used the green-chemistry-synthesis procedure, also known as the metathesis method, to develop three series of ionic liquids using 1-methyl-3-butyl imidazolium, butyl pyridinium, and diethyldibutylammonium as cations, and bromide (Br), methanesulfonate (CHSO), bis(trifluoromethanesulfonyl)imide (NTf), dichloroacetate (CHClCO), tetrafluoroborate (BF), and hydrogen sulfate (HSO) as anions. Spectroscopic methods were used to validate the structures of the lab-synthesized ILs. We performed an agar well diffusion assay by using pathogenic bacteria that cause various infections (; ; ; ; ; ; ) to scrutinize the in vitro antibacterial activity of the ILs. It was established that the nature and unique combination of the cations and anions were responsible for the antibacterial activity of the ILs. Among the tested ionic liquids, the imidazolium cation and NTf and HSO anions exhibited the highest antibacterial activity. The antibacterial potential was further investigated by in silico studies, and it was observed that bis(trifluoromethanesulfonyl)imide (NTf) containing imidazolium and pyridinium ionic liquids showed the maximum inhibition against the targeted bacterial strains and could be utilized in antibiotics. These antibacterial activities float the ILs as a promising alternative to the existing antibiotics and antiseptics.
Topics: Agar; Ammonium Compounds; Anions; Anti-Bacterial Agents; Anti-Infective Agents, Local; Bromides; Carbon Dioxide; Cations; Escherichia coli; Hydrocarbons, Fluorinated; Hydrogen; Imidazoles; Imides; Ionic Liquids; Mesylates; Pharmaceutical Preparations; Sulfates
PubMed: 36235187
DOI: 10.3390/molecules27196650