DNA-protein cross-links (DPCs) are highly toxic DNA lesions consisting of proteins covalently attached to chromosomal DNA. Unrepaired DPCs physically block DNA replication and transcription. Three DPC repair pathways have been identified in Arabidopsis (Arabidopsis thaliana) to date: the endonucleolytic cleavage of DNA by the structure-specific endonuclease MUS81; proteolytic degradation of the crosslinked protein by the metalloprotease WSS1A; and cleavage of the cross-link phosphodiester bonds by the tyrosyl phosphodiesterases TDP1 and TDP2. Here we describe the evolutionary conserved STRUCTURAL MAINTENANCE OF CHROMOSOMEs SMC5/6 complex as a crucial component involved in DPC repair. We identified multiple alleles of the SMC5/6 complex core subunit gene SMC6B via a forward-directed genetic screen designed to identify the factors involved in the repair of DPCs induced by the cytidine analog zebularine. We monitored plant growth and cell death in response to DPC-inducing chemicals, which revealed that the SMC5/6 complex is essential for the repair of several types of DPCs. Genetic interaction and sensitivity assays showed that the SMC5/6 complex works in parallel to the endonucleolytic and proteolytic pathways. The repair of zebularine-induced DPCs was associated with SMC5/6-dependent SUMOylation of the damage sites. Thus, we present the SMC5/6 complex as an important factor in plant DPC repair.

• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• DNA metabolismus   MeSH
• oprava DNA genetika   MeSH
• poškození DNA MeSH
• proteiny buněčného cyklu genetika   metabolismus   MeSH
• proteiny metabolismus   MeSH
• sumoylace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• proteiny buněčného cyklu MeSH
• proteiny MeSH

Loss of genome stability leads to reduced fitness, fertility and a high mutation rate. Therefore, the genome is guarded by the pathways monitoring its integrity and neutralizing DNA lesions. To analyze the mechanism of DNA damage induction by cytidine analog zebularine, we performed a forward-directed suppressor genetic screen in the background of Arabidopsis thaliana zebularine-hypersensitive structural maintenance of chromosomes 6b (smc6b) mutant. We show that smc6b hypersensitivity was suppressed by the mutations in EQUILIBRATIVE NUCLEOSIDE TRANSPORTER 3 (ENT3), DNA METHYLTRANSFERASE 1 (MET1) and DECREASE IN DNA METHYLATION 1 (DDM1). Superior resistance of ent3 plants to zebularine indicated that ENT3 is likely necessary for the import of the drug to the cells. Identification of MET1 and DDM1 suggested that zebularine induces DNA damage by interference with the maintenance of CG DNA methylation. The same holds for structurally similar compounds 5-azacytidine and 2-deoxy-5-azacytidine. Based on our genetic and biochemical data, we propose that zebularine induces enzymatic DNA-protein crosslinks (DPCs) of MET1 and zebularine-containing DNA in Arabidopsis, which was confirmed by native chromatin immunoprecipitation experiments. Moreover, zebularine-induced DPCs accumulate preferentially in 45S rDNA chromocenters in a DDM1-dependent manner. These findings open a new avenue for studying genome stability and DPC repair in plants.

• MeSH
• Arabidopsis MeSH
• cytidin analogy a deriváty   toxicita   MeSH
• DNA vazebné proteiny genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   MeSH
• heterochromatin účinky léků   metabolismus   MeSH
• léková rezistence MeSH
• membránové transportní proteiny genetika   MeSH
• mutace MeSH
• mutageny toxicita   MeSH
• proteiny buněčného cyklu genetika   MeSH
• proteiny huseníčku genetika   MeSH
• RNA ribozomální účinky léků   genetika   MeSH
• transkripční faktory genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AT4G05120 protein, Arabidopsis MeSH Prohlížeč
• cytidin MeSH
• DDM1 protein, Arabidopsis MeSH Prohlížeč
• DNA vazebné proteiny MeSH
• DNA-(cytosin-5-)methyltransferasa MeSH
• heterochromatin MeSH
• membránové transportní proteiny MeSH
• MET1 protein, Arabidopsis MeSH Prohlížeč
• mutageny MeSH
• proteiny buněčného cyklu MeSH
• proteiny huseníčku MeSH
• pyrimidin-2-one beta-ribofuranoside MeSH Prohlížeč
• RNA ribozomální MeSH
• RNA, ribosomal, 45S MeSH Prohlížeč
• SMC6B protein, Arabidopsis MeSH Prohlížeč
• transkripční faktory MeSH

Telomerase, an essential enzyme that maintains chromosome ends, is important for genome integrity and organism development. Various hypotheses have been proposed in human, ciliate and yeast systems to explain the coordination of telomerase holoenzyme assembly and the timing of telomerase performance at telomeres during DNA replication or repair. However, a general model is still unclear, especially pathways connecting telomerase with proposed non-telomeric functions. To strengthen our understanding of telomerase function during its intracellular life, we report on interactions of several groups of proteins with the Arabidopsis telomerase protein subunit (AtTERT) and/or a component of telomerase holoenzyme, POT1a protein. Among these are the nucleosome assembly proteins (NAP) and the minichromosome maintenance (MCM) system, which reveal new insights into the telomerase interaction network with links to telomere chromatin assembly and replication. A targeted investigation of 176 candidate proteins demonstrated numerous interactions with nucleolar, transport and ribosomal proteins, as well as molecular chaperones, shedding light on interactions during telomerase biogenesis. We further identified protein domains responsible for binding and analyzed the subcellular localization of these interactions. Moreover, additional interaction networks of NAP proteins and the DOMINO1 protein were identified. Our data support an image of functional telomerase contacts with multiprotein complexes including chromatin remodeling and cell differentiation pathways.

• Klíčová slova
• Arabidopsis, chromatin, folding, mitochondria, protein–protein interaction, replication, telomerase, transport,
• MeSH
• Arabidopsis metabolismus   MeSH
• genetická transkripce MeSH
• Golgiho aparát metabolismus   MeSH
• homeostáza telomer MeSH
• mapy interakcí proteinů MeSH
• mitochondrie metabolismus   MeSH
• multiproteinové komplexy metabolismus   MeSH
• nukleozomy metabolismus   MeSH
• peptidy metabolismus   MeSH
• posttranskripční úpravy RNA genetika   MeSH
• proteiny huseníčku chemie   metabolismus   MeSH
• proteiny vázající telomery metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• replikace DNA MeSH
• restrukturace chromatinu MeSH
• ribozomy metabolismus   MeSH
• telomerasa metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• multiproteinové komplexy MeSH
• nukleozomy MeSH
• peptidy MeSH
• proteiny huseníčku MeSH
• proteiny vázající telomery MeSH
• telomerasa MeSH

BACKGROUND: Acute acoustic trauma (AAT) ranks, among others, as one common cause of inner ear function impairment, especially in terms of military personnel, who are at an increased exposure to impulse noises from firearms. AIM OF THIS STUDY: 1. We wanted to demonstrate whether early treatment of AAT means a higher chance for the patient to improve hearing after trauma. 2. We find the answer to the question of whether hyperbaric oxygen therapy (HBO2) has a positive effect in the treatment of AAT. METHODS: We retrospectively analyzed data for the period 2004-2019 in patients with AAT. We evaluated the therapeutic success of corticosteroids and HBO2 in a cohort of patients with AAT n = 108 patients/n = 141 affected ears. RESULTS: Hearing improvement after treatment was recorded in a total of 111 ears (79%). In terms of the data analysis we were able to ascertain, utilizing success of treatment versus timing: within 24 h following the onset of therapy in 56 (40%) ears-54 (96%) ears had improved; within seven days following the onset the therapy was used in 55 (39%) ears-41 (74%) ears had improved; after seven days the therapy started in 30 (21%) ears-16 (53%) ears had improved. Parameter latency of the beginning of the treatment of AAT was statistically significant (p = 0.001 and 0.017, respectively). The success of the medical protocols was apparent in both groups-group I (treated without HBO2): n = 61 ears, of which 50 (82%) improved, group II (treated with HBO2): n = 73 ears, of which 56 (77%) improved. Group II shows improvement at most frequencies (500-2000 Hz). The most serious sensorineural hearing loss after AAT was at a frequency of 6000 Hz. CONCLUSION: Analysis of our data shows that there is a statistically significant higher rate of improvement if AAT treatment was initiated within the first seven days after acoustic trauma. Early treatment of AAT leads to better treatment success. HBO2 is considered a rescue therapy for the treatment of AAT. According to our recommendation, it is desirable to start corticosteroid therapy immediately after acoustic trauma. If hearing does not improve during the first seven days of corticosteroid therapy, then HBO2 treatment should be initiated.

• Klíčová slova
• acute acoustic trauma, hyperbaric oxygen therapy, noise induced hearing loss, tinnitus,
• MeSH
• hormony kůry nadledvin terapeutické užití   MeSH
• hyperbarická oxygenace * MeSH
• lidé MeSH
• nedoslýchavost z hluku * farmakoterapie   MeSH
• retrospektivní studie MeSH
• vojenský zdravotní systém * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• hormony kůry nadledvin MeSH

Fabry disease (FD) is a lysosomal storage disorder caused by pathogenic mutations in the alpha-galactosidase A (AGALA) encoding gene region. This rare disease affects several organs including the cochlea-vestibular system. Tinnitus and sensorineural hearing loss (SNHL) are reported among otoneurological symptoms. Early and correct diagnosis of FD is important with a view to available therapy. The aim of the study was to screen for alpha-galactosidase deficiency in men with tinnitus/SNHL. A prospective multicentric study including consecutive patients with SNHL confirmed by tone audiometry or tinnitus evaluated (10/2016-8/2019). The diagnosis of AGALA deficiency was done by dry blood spot method using a threshold of 1.2 µmol/l/h. Only men aged 18-60 were included. 181 patients were subject to evaluation. SNHL was reported in 126 (70%) patients, 50 (28%) patients had unilateral, 76 (42%) patients had bilateral SNHL. Tinnitus was found in 161 (89%) patients, unilateral in 96 (53%) and bilateral in 65 (36%) patients. Suspected FD was not detected in any patient; alpha-galactosidase The AGALA values ranged 1.5-8.8 µmol/l/h, an average of 3.4 µmol/l/h. None of the 181 patients participating in the study had AGALA levels below the threshold 1.2 µmol/l/h. The occurrence of tinnitus and sensorineural hearing loss in men appears to be an irrelevant clinical sign for FD systematic screening.

• Klíčová slova
• Alpha-galactosidase, Fabry disease, Screening, Sensorineural hearing loss, Tinnitus,
• MeSH
• alfa-galaktosidasa genetika   MeSH
• Fabryho nemoc * komplikace   diagnóza   epidemiologie   MeSH
• lidé MeSH
• percepční nedoslýchavost * diagnóza   MeSH
• prevalence MeSH
• prospektivní studie MeSH
• tinnitus * diagnóza   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alfa-galaktosidasa MeSH

Repetitive DNA sequences and some genes are epigenetically repressed by transcriptional gene silencing (TGS). When genetic mutants are not available or problematic to use, TGS can be suppressed by chemical inhibitors. However, informed use of epigenetic inhibitors is partially hampered by the absence of any systematic comparison. In addition, there is emerging evidence that epigenetic inhibitors cause genomic instability, but the nature of this damage and its repair remain unclear. To bridge these gaps, we compared the effects of 5-azacytidine (AC), 2'-deoxy-5-azacytidine (DAC), zebularine and 3-deazaneplanocin A (DZNep) on TGS and DNA damage repair. The most effective inhibitor of TGS was DAC, followed by DZNep, zebularine and AC. We confirmed that all inhibitors induce DNA damage and suggest that this damage is repaired by multiple pathways with a critical role of homologous recombination and of the SMC5/6 complex. A strong positive link between the degree of cytidine analog-induced DNA demethylation and the amount of DNA damage suggests that DNA damage is an integral part of cytidine analog-induced DNA demethylation. This helps us to understand the function of DNA methylation in plants and opens the possibility of using epigenetic inhibitors in biotechnology.

• Klíčová slova
• Arabidopsis thaliana, Vicia faba, DNA damage, DNA methylation, cytidine analog, epigenetic inhibitors, genome stability,
• MeSH
• adenosin analogy a deriváty   farmakologie   MeSH
• Arabidopsis genetika   MeSH
• azacytidin farmakologie   MeSH
• chromozomální aberace účinky léků   MeSH
• cytidin analogy a deriváty   farmakologie   MeSH
• decitabin farmakologie   MeSH
• epigeneze genetická * účinky léků   MeSH
• heterochromatin účinky léků   MeSH
• metylace DNA účinky léků   MeSH
• oprava DNA účinky léků   MeSH
• poškození DNA * účinky léků   MeSH
• RNA interference účinky léků   MeSH
• tandemové repetitivní sekvence účinky léků   MeSH
• umlčování genů * účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-deazaneplanocin MeSH Prohlížeč
• adenosin MeSH
• azacytidin MeSH
• cytidin MeSH
• decitabin MeSH
• heterochromatin MeSH
• pyrimidin-2-one beta-ribofuranoside MeSH Prohlížeč

Centromeres contain specialized nucleosomes at which histone H3 is partially replaced by the centromeric histone H3 variant cenH3 that is required for the assembly, maintenance, and proper function of kinetochores during mitotic and meiotic divisions. Previously, we identified a KINETOCHORE NULL 2 (KNL2) of Arabidopsis thaliana that is involved in the licensing of centromeres for the cenH3 recruitment. We also demonstrated that a knockout mutant for KNL2 shows mitotic and meiotic defects, slower development, reduced growth rate, and fertility. To analyze an effect of KNL2 mutation on global gene transcription of Arabidopsis, we performed RNA-sequencing experiments using seedling and flower bud tissues of knl2 and wild-type plants. The transcriptome data analysis revealed a high number of differentially expressed genes (DEGs) in knl2 plants. The set was enriched in genes involved in the regulation of the cell cycle, transcription, development, and DNA damage repair. In addition to comprehensive information regarding the effects of KNL2 mutation on the global gene expression, physiological changes in plants are also presented, which provides an integrated understanding of the critical role played by KNL2 in plant growth and development.

• Klíčová slova
• Arabidopsis, KNL2, RNA-seq, centromere, kinetochores,
• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• buněčný cyklus genetika   fyziologie   MeSH
• centromera genetika   metabolismus   MeSH
• DNA vazebné proteiny genetika   metabolismus   MeSH
• kinetochory metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• KNL2 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku MeSH

The article Ginkgo biloba extract EGb 761® versus pentoxifylline in chronic tinnitus: a randomized, double-blind clinical trial, written by Klára Procházková, Ivan Šejna, Jan Skutil and Aleš Hahn, was originally published electronically on the publisher's internet portal (currently SpringerLink).

• Publikační typ
• časopisecké články MeSH
• tisková chyba MeSH

Background Ginkgo biloba extract EGb 761® and pentoxifylline are frequently prescribed for the treatment of tinnitus. Objective To compare the treatment effects of Ginkgo biloba extract EGb 761R and pentoxifylline. Setting The study was performed at Department of Otorhinolaryngology of University Hospital Královské Vinohrady and 3rd Medical Faculty, Charles University in Prague. Method Patients with sub-chronic or chronic tinnitus were enrolled in double-blind trial and randomized to receive 120 mg EGb 761® or 600 mg pentoxifylline, each twice a day and in double-dummy fashion over a 12-week period. Main outcome measure changes in 11-Point Box Scales for tinnitus loudness and annoyance, the abridged Tinnitus Questionnaire (Mini-TQ), the Hospital Anxiety and Depression Scale (HADS), and the Sheehan Disability Scale (SDS). Results Full analysis set for efficacy analysis comprised 197 patients (EGb 761®, 99; pentoxifylline 98). For both treatment groups, significant improvements were observed in the Mini-TQ, the 11-Point Box Scales for tinnitus loudness and annoyance, the HADS anxiety score and the SDS. There was no relevant difference with regard to tinnitus-related outcomes between the two treatment groups. 20 adverse events were documented in EGb 761® group and 36 adverse events were reported for pentoxifylline group. No serious adverse event was reported during the study. Conclusion EGb 761® and pentoxifylline were similarly effective in reducing the loudness and annoyance of tinnitus as well as overall suffering of the patients. The incidence of adverse events was lower in the EGb 761® group.

• Klíčová slova
• Effectiveness, Ginkgo biloba, Pentoxifylline, Tinnitus,
• MeSH
• chronická nemoc MeSH
• dospělí MeSH
• dvojitá slepá metoda MeSH
• Ginkgo biloba MeSH
• lidé středního věku MeSH
• lidé MeSH
• pentoxifylin škodlivé účinky   terapeutické užití   MeSH
• psychiatrické posuzovací škály MeSH
• rostlinné extrakty škodlivé účinky   terapeutické užití   MeSH
• senioři MeSH
• tinnitus farmakoterapie   patofyziologie   psychologie   MeSH
• vazodilatancia škodlivé účinky   terapeutické užití   MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• Ginkgo biloba extract MeSH Prohlížeč
• pentoxifylin MeSH
• rostlinné extrakty MeSH
• vazodilatancia MeSH