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Wyszukujesz frazę "methylation" wg kryterium: Temat


Wyświetlanie 1-10 z 10
Tytuł:
Using capillary electrophoresis to study methylation effect on RNA-peptide interaction.
Autorzy:
Mucha, Piotr
Szyk, Agnieszka
Rekowski, Piotr
Agris, Paul
Powiązania:
https://bibliotekanauki.pl/articles/1043465.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
methylated nucleosides
methylation
arginine methylation
RN-peptide interaction
capillary electrophoresis
Opis:
Methylation of RNA and proteins is one of a broad spectrum of post-transcriptional/translational mechanisms of gene expression regulation. Its functional signification is only beginning to be understood. A sensitive capillary electrophoresis mobility shift assay (CEMSA) for qualitative study of the methylation effect on biomolecules interaction is presented. Two RNA-peptide systems were chosen for the study. The first one consists of a 17-nucleotide analogue (+27-+43) of the yeast tRNAPhe anticodon stem and loop domain (ASLPhe) containing three of the five naturally occurring modifications (2'-O-methylcytidine (Cm32), 2'-O-methylguanine (Gm34) and 5-methylcytidine (m5C40)) (ASLPhe-Cm32,Gm34,m5C40) and a 15-amino-acid peptide (named tF2 : Ser1-Ile-Ser-Pro-Trp5-Gly-Phe-Ser-Gly-Leu10-Leu- Arg-Trp-Ser-Tyr15) selected from a random phage display library (RPL). A peptide-concentration-dependent formation of an RNA-peptide complex was clearly observable by CEMSA. In the presence of the peptide the capillary electrophoresis (CE) peak for triply methylated ASLPhe shifted from 18.16 to 20.90 min. Formation of the complex was not observed when an unmethylated version of ASLPhe was used. The second system studied consisted of the (+18)-(+44) fragment of the trans-activation response element of human immunodeficiency virus type 1 (TAR RNA HIV-1) and a 9-amino-acid peptide of the trans-activator of transcription protein (Tat HIV-1) Tat(49-57)-NH2 (named Tat1 : Arg49-Lys-Lys-Arg52-Arg-Gln-Arg-Arg- Arg57-NH2). In the presence of Tat(49-57)-NH2 a significant shift of migration time of TAR from 18.66 min to 20.12 min was observed. Methylation of a residue Arg52→Arg(Me)2, crucial for TAR binding, strongly disrupted formation of the complex. Only at a high micromolar peptide concentration a poorly shaped, broad peak of the complex was observed. CE was found to be an efficient and sensitive method for the analysis of methylation effects on interaction of biomolecules.
Źródło:
Acta Biochimica Polonica; 2003, 50, 3; 857-864
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mammalian DNA methyltransferases
Autorzy:
Siedlecki, Pawel
Zielenkiewicz, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1041231.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
DNA methyltransferases
DNA methylation
Opis:
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.
Źródło:
Acta Biochimica Polonica; 2006, 53, 2; 245-256
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global quantification of heterochromatin-associated histone methylations in cell lines with differential sensitivity to ionizing radiation
Autorzy:
Cetinkaya, Merve
Özgür, Emre
Dalay, Nejat
Gezer, Ugur
Powiązania:
https://bibliotekanauki.pl/articles/1039084.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
histone methylation
heterochromatin
radiosensitivity
ELISA immunoassay
Opis:
Histone modifications are involved in the DNA damage response (DDR). Here, by utilizing an ELISA immunoassay we assessed the methylation at H3K9 (H3K9me2 and H3K9me3) in two cell lines with differential sensitivity to radiation-induced apoptosis, HeLa (sensitive) and MCF-7 (resistant). We found that DNA damage induction by γ-irradiation leads to considerable accumulation (up to 5-fold) of H3K9me2 and H3K9me3, but not of H4K20me3 (control modification) in MCF-7 cells (p<0.05). Interestingly, a lower dose (2 Gy) was more effective than 5 Gy. In HeLa cells a smaller effect (approx. 1.5-1.8-fold) was evident only at 5 Gy. In conclusion, our findings reveal that DNA damage leads to specific accumulation of H3K9me2 and H3K9me3 in a cell-type specific manner.
Źródło:
Acta Biochimica Polonica; 2015, 62, 2; 173-176
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SOCS3 is epigenetically up-regulated in steroid resistant nephrotic children
Autorzy:
Zaorska, Katarzyna
Zawierucha, Piotr
Ostalska-Nowicka, Danuta
Nowicki, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1038853.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
methylation
nephrotic syndrome
single nucleotide polymorphism
steroid resistance
Opis:
Background. The mechanism of steroid resistance in children with the nephrotic syndrome is yet unknown. About 20% of patients demonstrate steroid unresponsiveness and progress to end stage renal disease. Aberrant SOCS3 and SOCS5 expression in steroid resistant and sensitive patients has previously been demonstrated. Here, we investigate genetic and epigenetic mechanisms of regulation of SOCS3 and SOCS5 transcription in nephrotic children. Methods. 76 patients with the nephrotic syndrome (40 steroid resistant and 36 steroid sensitive) and 33 matched controls were included in this study. We performed genotyping of a total of 34 single nucleotide polymorphisms for SOCS3 and SOCS5 promoters and evaluated their methylation status using MS-PCR and QMSP methods. Results. Steroid resistant patients had a significantly lower methylation of one region of SOCS3 promoter in comparison with steroid sensitive patients and controls (p < 0.0001). However, the relative methylation level in the steroid sensitive patients and controls differed significantly even before the first steroid dose (p = 0.001758). Other SOCS3 and SOCS5 promoter regions displayed no differences in methylation or were fully methylated/unmethylated in all study groups, showing site-specific methylation. The allele and genotype distribution for SOCS3 and SOCS5 markers did not differ statistically between the groups. Conclusions. We demonstrate an epigenetic mechanism of SOCS3 up-regulation in steroid resistant children with the nephrotic syndrome. The assessment of methylation/unmethylation of SOCS3 promoter might be an early marker for steroid responsiveness in NS patients.
Źródło:
Acta Biochimica Polonica; 2016, 63, 1; 131-138
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of DNA methylation and hydroxymethylation in plant protoplast cultures
Autorzy:
Moricová, Pavla
Ondřej, Vladan
Navrátilová, Božena
Luhová, Lenka
Powiązania:
https://bibliotekanauki.pl/articles/1039600.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Brassica oleracea
DNA hydroxymethylation
Cucumis sativus
protoplasts
DNA methylation
Opis:
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.
Źródło:
Acta Biochimica Polonica; 2013, 60, 1; 33-36
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
H3K4 histone methylation in oral squamous cell carcinoma
Autorzy:
Mancuso, Marta
Matassa, Danilo
Conte, Mariachiara
Colella, Giuseppe
Rana, Gina
Fucci, Laura
Piscopo, Marina
Powiązania:
https://bibliotekanauki.pl/articles/1040528.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
oral squamous carcinoma
histone methylation
H3K4
Opis:
Methylation of specific lysine residues in histone tails has been proposed to function as a stable epigenetic marker that directs biological functions altering chromatin structure. Recent findings have implicated alteration in heterochromatin formation as a contributing factor in cancer development. In order to verify whether changes in the overall level of H3K4 histone methylation could be involved in oral squamous carcinoma, the levels of H3K4me1, me2 and me3 were measured in oral squamous carcinoma, leukoplakias and normal tissues. The levels of H3K4me2 and me3 were significantly different in oral squamous cell carcinoma in comparison with normal tissue: the level of H3K4me2 was increased while that of H3K4me3 decreased. No significant differences could be found between the two types of tissues in the level of H3K4me1. A similar trend was found in the leukoplakias that appeared more like the pathological than normal tissue. These results support the idea that alteration of chromatin structure could contribute to oncogenic potential.
Źródło:
Acta Biochimica Polonica; 2009, 56, 3; 405-410
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methylenetetrahydrofolate reductase gene polymorphisms in Egyptian Turner Syndrome patients
Autorzy:
Ismail, Manal
Zarouk, Waheba
Ruby, Mona
Mahmoud, Wael
Gad, Randa
Powiązania:
https://bibliotekanauki.pl/articles/1038999.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
chromosomal nondisjunction
DNA methylation
folate
MTHFR gene
Turner Syndrome
Opis:
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.
Źródło:
Acta Biochimica Polonica; 2015, 62, 3; 529-532
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of the in vitro genotoxicity of anticancer drugs idarubicin and mitoxantrone.
Autorzy:
Błasiak, Janusz
Gloc, Ewa
Warszawski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/1043821.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
mitoxantrone
oxidative DNA damage
DNA damage
idarubicin
comet assay
DNA methylation
DNA repair
Opis:
Idarubicin is an anthracycline antibiotic used in cancer therapy. Mitoxantrone is an anthracycline analog with presumed better antineoplastic activity and lesser toxicity. Using the alkaline comet assay we showed that the drugs at 0.01-10 μM induced DNA damage in normal human lymphocytes. The effect induced by idarubicin was more pronounced than by mitoxantrone (P < 0.001). The cells treated with mitoxantrone at 1 μM were able to repair damage to their DNA within a 30-min incubation, whereas the lymphocytes exposed to idarubicin needed 180 min. Since anthracyclines are known to produce free radicals, we checked whether reactive oxygen species might be involved in the observed DNA damage. Catalase, an enzyme inactivating hydrogen peroxide, decreased the extent of DNA damage induced by idarubicin, but did not affect the extent evoked by mitoxantrone. Lymphocytes exposed to the drugs and treated with endonuclease III or formamidopyrimidine-DNA glycosylase (Fpg), enzymes recognizing and nicking oxidized bases, displayed a higher level of DNA damage than the untreated ones. 3-Methyladenine-DNA glycosylase II (AlkA), an enzyme recognizing and nicking mainly methylated bases in DNA, increased the extent of DNA damage caused by idarubicin, but not that induced by mitoxantrone. Our results indicate that the induction of secondary malignancies should be taken into account as side effects of the two drugs. Direct strand breaks, oxidation and methylation of the DNA bases can underlie the DNA-damaging effect of idarubicin, whereas mitoxantrone can induce strand breaks and modification of the bases, including oxidation. The observed in normal lymphocytes much lesser genotoxicity of mitoxantrone compared to idarubicin should be taken into account in planning chemotherapeutic strategies.
Źródło:
Acta Biochimica Polonica; 2002, 49, 1; 145-155
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantification of 5-methyl-2-deoxycytidine in the DNA
Autorzy:
Giel-Pietraszuk, Małgorzata
Insińska-Rak, Małgorzata
Golczak, Anna
Sikorski, Marek
Barciszewska, Mirosława
Barciszewski, Jan
Powiązania:
https://bibliotekanauki.pl/articles/1039105.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
DNA methylation
3,N4-etheno-5-methyl-2'deoxcytidine
fluorescence
RP-HPLC
Opis:
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.
Źródło:
Acta Biochimica Polonica; 2015, 62, 2; 281-286
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sequence determination and analysis of S-adenosyl-L-homocysteine hydrolase from yellow lupine (Lupinus luteus).
Autorzy:
Brzeziński, Krzysztof
Janowski, Robert
Podkowiński, Jan
Jaskólski, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/1044143.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Southern blot
S-adenosyl-L-homocysteinase
Northern blot
biological methylation
screening of cDNA library
phylogeny
Opis:
The coding sequences of two S-adenosyl-L-homocysteine hydrolases (SAHases) were identified in yellow lupine by screenig of a cDNA library. One of them, corresponding to the complete protein, was sequenced and compared with 52 other SAHase sequences. Phylogenetic analysis of these proteins identified three groups of the enzymes. Group A comprises only bacterial sequences. Group B is subdivided into two subgroups, one of which (B1) is formed by animal sequences. Subgroup B2 consist of two distinct clusters, B2a and B2b. Cluster B2b comprises all known plant sequences, including the yellow lupine enzyme, which are distinguished by a 50-residue insert. Group C is heterogeneous and contains SAHases from Archaea as well as a new class of animal enzymes, distinctly different from those in group B1.
Źródło:
Acta Biochimica Polonica; 2001, 48, 2; 477-483
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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