Wyniki wyszukiwania - Biblioteka Nauki

1

Mammalian DNA methyltransferases

100%

Siedlecki P. , Zielenkiewicz P.

Acta Biochimica Polonica

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2006

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tom 53

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nr 2

245-256

EN

DNA methylation is an epigenetic process affecting gene expression and chromatin organization. It can heritably silence or activate transcription of genes without any change in their nucleotide sequences, and for a long time was not recognized as an important regulatory mechanism. However, during the recent years it has been shown that improper methylation, especially hypermethylation of promoter regions, is observed in nearly all steps of tumorigenesis. Aberrant methylation is also the cause of several major pathologies including developmental disorders involving chromosome instabilities and mental retardation. A great progress has been made in our understanding of the enzymatic machinery involved in establishing and maintaining methylation patterns. This allowed for the development of new diagnostic tools and epigenetic treatment therapies. The new approaches hold a great potential; several inhibitors of DNA methyltransferases have already shown very promising therapeutic effects.

2

Quantification of 5-methyl-2'-deoxycytidine in the DNA

80%

Giel-Pietraszuk M. , Insińska-Rak M. , Golczak A. , Sikorski M. , Barciszewska M. , Barciszewski J.

Acta Biochimica Polonica

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2015

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tom 62

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nr 2

281-286

EN

Methylation at position 5 of cytosine (Cyt) at the CpG sequences leading to formation of 5-methyl-cytosine (m5Cyt) is an important element of epigenetic regulation of gene expression. Modification of the normal methylation pattern, unique to each organism, leads to the development of pathological processes and diseases, including cancer. Therefore, quantification of the DNA methylation and analysis of changes in the methylation pattern is very important from a practical point of view and can be used for diagnostic purposes, as well as monitoring of the treatment progress. In this paper we present a new method for quantification of 5-methyl-2'deoxycytidine (m5C) in the DNA. The technique is based on conversion of m5C into fluorescent 3,N4-etheno-5-methyl-2'deoxycytidine (εm5C) and its identification by reversed-phase high-performance liquid chromatography (RP-HPLC). The assay was used to evaluate m5C concentration in DNA of calf thymus and peripheral blood of cows bred under different conditions. This approach can be applied for measuring of 5-methylcytosine in cellular DNA from different cells and tissues.

3

miR-29a and miR-30c negatively regulate DNMT 3a in cardiac ischemic tissues: implications for cardiac remodelling

80%

Gambacciani C. , Kusmic C. , Chiavacci E. , Meghini F. , Rizzo M. , Mariani L. , Pitto L.

microRNA Diagnostics and Therapeutics

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2014

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tom 1

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nr 1

EN

Recent evidences indicate that epigenetic changes play an important role in the transcriptional reprogramming of gene expression that characterizes cardiac hypertrophy and failure and may dictate response to therapy. Several data demonstrate that microRNAs (miRNAs) play critical roles both in normal cardiac function and under pathological conditions. Here we assessed, in in vivo rat models of myocardial infarction (MI) and ischemia-reperfusion (IR), the relationship between two miRNAs (miR-29a and miR-30c) and de novo methyltransferase (DNMT3a) which, altering the chromatin accessibility for transcription factors, deeply impacts gene expression. We showed that the levels of members of miR-29 and miR- 30 families were down regulated in ischemic tissues whilst the protein levels of DNMT3a were increased, such a relation was not present in healthy tissues. Furthermore, by an in vitro assay, we demonstrated that both miRNAs are able to down regulate DNMT3a by directly interacting with DNMT3a 3’UTR and that miR-29a or miR-30c overexpression in the cardiac HL1 cell line causes decrease of DNMT3a enzyme both at the mRNA and protein levels. Our data, besides confirming the down regulation of the miR-29a and miR-30c in infarcted tissues, envisage a cross-talk between microRNAs and chromatin modifying enzymes suggesting a new mechanism that might generate the alterations of DNA methylation often observed in myocardial pathophysiology.

4

Biochemical characteristics of the chromatin-remodeling enzyme DDM1

80%

Brzeski J.

Polish Journal of Natural Sciences. Supplement

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2003

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tom 01

5

Correlation of chromosome damage and promoter methylation status of the DNA repair genes MGMT and hMLH1 in Chinese vinyl chloride monomer (VCM)-exposed workers

70%

Wu F. , Liu J. , Qiu Y.-L. , Wang W. , Zhu S.-M. , Sun P. , Miao W.-B. , Li Y.-L. , Brandt-Rauf P. W. , Xia Z.-L.

International Journal of Occupational Medicine and Environmental Health

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2013

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tom 26

|

nr 1

173-182

EN

Objective: To explore the association of the methylation status of MGMT and hMLH1 with chromosome damage induced by vinyl chloride monomer (VCM). Materials and Methods: Methylation of MGMT and hMLH1 was measured in 101 VCM-exposed workers by methylation-specifi c PCR. Chromosome damage in peripheral blood lymphocytes was measured by the cytokinesis-block micronucleus assay. The subjects were divided into chromosome damaged and non-damaged groups based on the normal reference value of micronuclei frequencies determined for two control groups. Results: MGMT promoter methylation was detectable in 5 out of 49 chromosome damaged subjects, but not in the chromosome non-damaged subjects; there was a signifi cant difference in MGMT methylation between the two groups (p < 0.05). Conclusions: We detected aberrant promoter methylation of MGMT in a small number of chromosome damaged VCM-exposed workers, but not in the chromosome non-damaged subjects. This preliminary observation warrants further investigation in a larger study.

6

Olsalazine inhibits cell proliferation and DNA methylation in canine lymphoid tumor cell lines

70%

Itoh S. , Yamazaki J. , Iwahana M. , Tsukamoto A. , Itoh S. , Yamazaki J. , Iwahana M. , Tsukamoto A.

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7

Role of genomic imprinting in endosperm development

70%

Scott R. J. , Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, U.K.

Acta Biologica Cracoviensia. Series Botanica. Supplement

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2005

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tom 47

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nr 1

8

Changes of DNA methylation and hydroxymethylation in plant protoplast cultures

70%

Moricová P. , Ondřej V. , Navrátilová B. , Luhová L.

Acta Biochimica Polonica

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2013

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tom 60

|

nr 1

33-36

EN

Cytosine methylation patterns in higher eukaryotes are important in gene regulation. Along with 5-methylcytosine (5-mC), a newly discovered constituent of mammalian DNA, 5-hydroxymethylcytosine (5-hmC), is the other modified base in higher organisms. In this study we detected 5-hmC in plant protoplast DNA and demonstrated its increasing content during the first 72 hrs. of protoplast cultivation. In contrast to 5-hmC, the amount of 5-mC decreased during protoplast cultivation. It was also found that 5-hmC did not primarily arise as a product of oxidative DNA damage following protoplast culture.

9

Methylenetetrahydrofolate reductase gene polymorphisms in Egyptian Turner Syndrome patients

70%

Ismail M. , Zarouk W. , Ruby M. , Mahmoud W. , Gad R.

Acta Biochimica Polonica

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2015

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tom 62

|

nr 3

529-532

EN

Background: Folate metabolism dysfunctions can result in DNA hypomethylation and abnormal chromosome segregation. Two common polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) encoding gene (C677T and A1298C) reduce MTHFR activity, but when associated with aneuploidy, the results are conflicting. Turner Syndrome (TS) is an interesting model for investigating the association between MTHFR gene polymorphisms and nondisjunction because of the high frequency of chromosomal mosaicism in this syndrome. Objective: To investigate the association of MTHFR gene C677T and A1298C polymorphisms in TS patients and their mothers and to correlate these polymorphisms with maternal risk of TS offspring. Subjects and Methods: MTHFR C677T and A1298C polymorphisms were genotyped in 33 TS patients, their mothers and 15 healthy females with their mothers as controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing technique. Results: Genotype and allele frequencies of both C677T and A1298C were not significantly different between TS cases and controls. There were no significant differences in C677T genotype distribution between the TS mothers and controls (p=1). The MTHFR 1298AA and 1298AC genotypes were significantly increased in TS mothers Vs. control mothers (p=0.002). The C allele frequency of the A1298C polymorphism was significantly different between the TS mothers and controls (p=0.02). The association of A1298C gene polymorphism in TS patients was found to increase with increasing age of both mothers (p=0.026) and fathers (p=0.044) of TS cases. Conclusion: Our findings suggest a strong association between maternal MTHFR A1298C and risk of TS in Egypt.

10

Exogenous steroid hormones stimulate full development of autonomous endosperm in Arabidopsis thaliana

70%

Rojek J. , Pawelko L. , Kapusta M. , Naczk A. , Bohdanowicz J.

Acta Societatis Botanicorum Poloniae

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2015

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tom 84

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nr 2

EN

Most flowering plants, including important crops, require double fertilization to form an embryo and endosperm, which nourishes it. Independence from fertilization is a feature of apomictic plants that produce seeds, from which the plants that are clones of the mother plant arise. The phenomenon of apomixis occurs in some sexual plants under specific circumstances. Since the launch of a fertilization-independent mechanism is considered a useful tool for plant breeding, there have been efforts to artificially induce apomixis. We have been able to produce fertilization-independent endosperm in vitro in Arabidopsis over the last few years. This paper demonstrates the methods of improving the quality of the endosperm obtained using plant and mammalian steroid hormones. Additionally, it shows the study on the autonomous endosperm (AE) formation mechanism in vitro. This paper examines the effect of exogenous steroid hormones on unfertilized egg and central cell divisions in culture of unpollinated pistils of Arabidopsis Col-0 wild-type andfie-1 mutant. All media with hormones used (estrone, androsterone, progesterone, and epibrassinolide) stimulated central cell divisions and fertilization-independent endosperm development. The stages of AE development followed the pattern of Arabidopsis thaliana wild type after fertilization. Subsequent stages of AE were observed from 2-nuclear up to cellular with the most advanced occurring on medium with 24-epibrassinolide and progesterone. The significant influence of mammalian sex hormones on speed of AE development and differentiation was noticed. Using restriction analysis, the changes in methylation of FIE gene was established under in vitro condition. The authors of this paper showed that Arabidopsis thaliana has a high potency to fertilization-independent development.

11

Exposure to Maternal Diabetes in Utero and DNA Methylation Patterns in the Offspring

70%

West N. A. , Kechris K. , Dabelea D.

Immunometabolism

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2013

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tom 1

1-9

EN

Perturbations in early life environments, including intrauterine exposure to maternal gestational diabetes (GDM), are hypothesized to lead to metabolic imprinting resulting in increased risk of cardiometabolic outcomes later in life. We aimed to 1) identify candidate genes and biological pathways associated with differentially methylated regions (DMRs) in relation to exposure to GDM in utero and, 2) using mediation analysis, more definitively investigate the potential for mediation of the effect of exposure to maternal diabetes in utero on cardiometabolic traits in childhood risk through our identified DMRs. Genome-wide methylation analysis of peripheral blood mononuclear cell’s DNA was conducted in 21 healthy children, ages 8-12 years. P-values from multiple linear regression analyses for >27,000 CpG sites were ranked to identify DMRs between the exposure groups. Among the top 10 ranked DMRs, we identified several genes, including NPR1, PANK1, SCAND1, and GJA4, which are known to be associated with cardiometabolic traits. Gene enrichment analysis of the top 84 genes, each with p<=0.005, identified the ubiquitin proteasome system (UPS) as the most enriched biological pathway (p = 0.07). The UPS pathway reflects biological processes known to be associated with endothelial function, inflammation, lipid metabolism, insulin resistance and b-cell apoptosis, whose derangements are central to the pathogenesis of cardiometabolic diseases. Increased methylation of PYGO1 and CLN8 had the greatest relative mediation effect (RME = 87%, p=0.005 and RME=50%, p=0.01) on the impact of exposure to maternal diabetes in utero on VCAM-1 levels in the offspring. Multiple candidate genes and the UPS were identified for future study as possible links between exposure to maternal gestational diabetes in utero and adverse cardiometabolic traits in the offspring. In particular, increased methylation of PYGO1 and CLN8 may be biological links between intrauterine exposure to maternal diabetes and significantly increased VCAM-1 levels in the offspring.

12

The role of DNA methylation in cancer development

70%

Luczak M. W. , Jagodzinski P. P.

Folia Histochemica et Cytobiologica

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2006

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tom 44

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nr 3

13

Methylation pattern analysis of the sequences conding the 18S and 15SrRNA genes in the genomic DNA of wheat callus tissues

70%

Zubek W. , Dabrowska G. , Szechynska M. , Filek M.

Polish Journal of Natural Sciences. Supplement

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2003

|

tom 01

14

Demethylation of the sex-determining region Y gene promoter and incidence of disorder of sex development in cloned dog males

60%

Hwang K. C. , Choi Y. K. , Jeong Y. I. , Park K. B. , Choi E. J. , Jeong Y. W. , Hossein M. S. , Hyun S. H. , Jeung E.-B. , Hwang W. S.

Journal of Physiology and Pharmacology

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2020

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tom 71

|

nr 3

15

The effect of DNA methyltransferase and histone deacetylase inhibitors on αKlotho gene expression in bladder cancer T24 cell line

60%

Szymczyk A. , Forma E.

Folia Medica Lodziensia

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2014

|

tom 41

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nr 2

111-119

EN

Introduction: αKlotho gene was originally identified as a putative agesuppressing gene in mice. Recently it is known that αKlotho gene functions as a tumor suppressor in many types of cancer, including breast, pancreas, gastric, colon, lung and cervical cancer. The downregulation of αKlotho expression was associated with CpG hipermethylation of promoter region and histone deacetylation. Bladder cancer is the most common cancer of the urinary tract in Polish population. The aim of this study was the analysis of the effect of DNA methyltransferase and histone deacetylase inhibitors on αKlotho gene expression in bladder cancer cells. Materials and methods: In this study T24 bladder cancer cell line was used. The analysis of the effect of DNA methyltransferase and histone deacetylase inhibitors on αKlotho gene expression was performed using Real Time PCR method with TaqMan probes. To determine the methylation profile of αKlotho gene promoter region quantitive Methylation-Specific Polymerase Chain Reaction technique was used. Results: The treatment of T24 cells with DNA methyltransferase inhibitor (AZA) restored the expression of αKlotho gene. After AZA treatment, the methylation level of CpG island in the promoter region of αKlotho gene was nearly half lower (p<0.05) than control cells. In case of the treatment of T24 cells with histone deacetylase inhibitor (TSA) we did not observe any changes in αKL gene expression in respect to the control cells. Treatment cells with both the inhibitors led to the significant increase of mRNA αKlotho gene expression level (p<0.001). Conclusions: The changes in αKlotho gene expression on mRNA level are associated with epigenetic changes.

PL

Wstęp: Gen αKlotho pierwotnie zidentyfikowany został u myszy jako gen, którego ekspresja wpływa na długość ich życia. Obecnie wiadomo, że αKlotho spełnia funkcję genu supresorowego w przypadku wielu typów nowotworów, m.in. w raku piersi, trzustki, żołądka, płuc, okrężnicy i raku szyjki macicy. Wykazano, że spadek ekspresji genu αKlotho związany jest z hipermetylacją wysp CpG w obrębie regionu promotorowego oraz deacetylacją histonów. Rak pęcherza moczowego jest najczęściej występującym nowotworem układu moczowego w Polsce. Celem prowadzonych badań była analiza wpływ inhibitorów metylotransferaz DNA oraz deacetylaz białek histonowych na ekspresję genu αKlotho w komórkach raka pęcherza moczowego. Materiały i metody: Materiał do badań stanowiła linia komórek raka pęcherza moczowego T24. Analizę wpływu inhibitorów metylotransferaz DNA oraz deacetylaz białek histonowych na ekspresję genu αKlotho prowadzono techniką Real Time PCR z użyciem sond fluorescencyjnych TaqMan. Ocenę stopnia metylacji regionu promotorowego badanego genu prowadzono przy użyciu techniki ilościowego MSP-PCR (ang. Methylation-Specific Polymerase Chain Reaction). Wyniki: W wyniku traktowania komórek linii T24 inhibitorem metylotransferaz DNA (AZA) obserwowano przywrócenie ekspresji genu αKlotho. W porównaniu do komórek kontrolnych, komórki traktowane 5-aza-2′-deoksycytydyną wykazywały blisko o połowę niższy stopień metylacji wysp CpG w regionie promotorowym genu αKlotho (p<0,05). W wyniku traktowania komórek inhibitorem deacetylaz białek histonowych (TSA) nie obserwowano zmian w ekspresji genu αKL. Zastosowanie obu inhibitorów prowadziło do istotnego wzrostu ekspresji genu αKlotho na poziomie mRNA (p<0,001). Wnioski: Zmiany ekspresji genu αKlotho na poziomie mRNA związane są ze zmianami we wzorze modyfikacji epigenetycznych.

16

Novobiocin sensitivity of Salmonella typhimurium dam and/or seqA mutants

60%

Chatti A. , Aloui M. , Tagourti J. , Mihoub M. , Landoulsi A.

Polish Journal of Microbiology

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2014

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tom 63

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nr 1

EN

This study was carried out to determine the effects of novobiocin, a gyrase inhibitor, on the growth, survival, motility and whole cell proteins of S. Typhimurium dam and/or seqA strains. Our results showed that the dam and seqA/dam mutants are the most sensitive to novobiocin, compared to wild type and seqA strains. Surprisingly, the motility of seqA mutants increased after exposure to novobiocin only in stationary phase cells. All the other strains showed a significant decrease in their motility. The analysis of protein profiles of all strains demonstrated several modifications as manifested by the alteration of the expression levels of certain bands. Our work is therefore of great interest in understanding the effects of novobiocin on S. Typhimurium and the involvement of DNA methylation.

17

The analysis of Fanconi anemia/BRCA pathway genesin laryngeal carcinoma

60%

Szaumkessel M.

Polski Przegląd Otorynolaryngologiczny

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2014

|

tom 3(4)

250-252

PL

Summary of Doctoral Thesis/Streszczenie pracy doktorskiej

18

Changes in DNA methylation in maize under herbicide stress conditions

60%

Tyczewska A. , Gracz J. , Szymkowiak J. , Twardowski T.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2015

|

tom 96

|

nr 1

19

DNA methylation dynamics under drought stress in barley

60%

Chwialkowska K. , Szarejko I. , Kwasniewski M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

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2013

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tom 94

|

nr 3

20

Epigenetic control of the cellular processes

60%

Pawlicka K. , Perrigue P. , Barciszewski J.

Nauka

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2018

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nr 2