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Epigenetic mechanisms in the regulation of the B7-H1 and IRF-1 expression in tumour cells.
Hrušková, Veronika ; Reiniš, Milan (advisor) ; Krulová, Magdaléna (referee)
Interferon γ is an important T-cell helper type 1 (Th1) cytokine involves in antimicrobial immunity. It is a part of the inflammatory immune response in the site of infection. However, for its proper function, the regulation of immunity is necessary to avoid injury of the tissue caused by long-term inflammation. While interferon γ triggers expression of proinflammatory genes, it also regulates genes which inactivate immune response. The B7-H1 molecule belongs among these inhibitory regulators. Furthermore, antitumour effect of interferon γ is well-known as well. After extensive experiments, interferon γ was tested as an immunotherapeutic drug against melanomas in clinical trials. However, the trials had to be terminated prematurely because of unsuccessful results. It started to be clear that interferon γ could have also a protumour effect. Interferon γ upregulates the expression of B7-H1 molecule which aids tumour in escape from immunity. The B7-H1 molecule possesses a binding site for interferon regulatory factor 1 (IRF-1) in its promoter region. This IRF-1 is induced by interferon γ - JAK/STAT signalling pathway. In our previous research, we observed interferon γ induced DNA demethylation of promoters in genes that are involved in antigen presenting machinery. Additionally, DNA methylation of...
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Epigenetics mechanisms
Šornová, Veronika ; Černá, Marie (advisor) ; Koc, Michal (referee)
Epigenetics is the study of heritable changes in gene activities that are not caused by changes in the DNA sequence. Epigenetic mechanisms can be employed at many levels, from transcription to translation. They include DNA methylation, histone modification, and with it connected chromatin modification, and RNA interference. The result is the change of chromatin conformation leading to decrease or increase of certain gene expression, X-chromosome inactivation or gene imprinting. Epigenetic regulation plays important role in etiopatogenesis of multifactorial diseases. Genetic predisposing factors (in autoimmune diseases there are genes of major histocompatibility complex) and environmental factors, which affect our genome just through epigenetic modifications, are involved in their manifestation. Key words: Epigenetic mechanisms, DNA methylation, histone modification, RNA interference, genomic imprinting, X-chromosome inactivation, multifactorial disease.
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Forensic analysis of epigenetic factors and mRNA
Andreasová, Karolina ; Šimková, Halina (advisor) ; Zachová, Markéta (referee)
In last years, forensic genetics focused on a research of epigenetic factors and mRNA. It turned out that their analysis provides valuable information that can be obtained from a small amount of a biological trace and which included e.g. estimation of circumstances of death, age estimation, discrimination within monozygotic twins, identification of tissues and body fluids, sample authentication, determination of paternal allele, etc. In this thesis, it is discussed methods of epigenetic factors and mRNA analysis and their potential application in future forensic practice.
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Role of the FTO gene in the genetic determination of common multifactorial diseases
Dlouhá, Dana ; Hubáček, Jaroslav (advisor) ; Černá, Marie (referee) ; Rossmeislová, Lenka (referee)
Obesity is a risk factor for development of cardiovascular disease, diabetes type 2 and some cancers. Newly detected genetic risk factor for body weight is the FTO gene ("fat mass and obesity associated"). The aim of this thesis was determine 1) whether the presence of risk alleles correlate with BMI in Czech population and to determine 2) whether there is an association between variants in the FTO gene and risk of myocardial infarction/ acute coronary syndrome (MI/ ACS), 3) renal failure (ESRD), or 4) incidence of colorectal cancer (CRC). We analyzed polymorphisms rs17817449 (first intron) and rs17818902 (3rd intron) using by PCR-RFLP and then also RT PCR. We found an association of the first intron variant (but not the 3rd one) and BMI in Czech control population. We have detected an association of 1st intron SNP and BMI changes during the intervention study in obese children, but not in obese females. We found a correlation between the risk allele and increased risk of ACS (OR 1.49) in patients with MI. In patients with ESRD was detected association between the risk allele and the risk of disease (OR 1.37). We didn't confirmed the association between rs17817449 and the development of CRC. Representative selected groups of the Czech populations "MONICA" and "HAPPIE" were used as controls. One...
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RNA directed DNA methylation in Arabidopsis thaliana
Motylová, Šárka ; Fischer, Lukáš (advisor) ; Moravec, Tomáš (referee)
The differential transcriptional activity of the genome is provided by epigenetic modifications, which include DNA methylation, alteration of histone N-terminal amino acids and changes in histone variants. RNA interference is a regulatory process, in which transcriptional or post-transcriptional silencing of exogenous or endogenous sequences is mediated by the action of small RNAs derived from these sequences. The 24-nucleotide siRNAs, forming a fraction of small RNAs, direct de novo DNA methylation and participate in the maintenance of DNA methylation (RNA-directed DNA methylation; RdDM), which facilitates transcriptional silencing of heterochromatin and transposable elements representing a large part of plant genomes. The presence of two RNA polymerases involved in this pathway is characteristic for flowering plants, which were discovered for the first time in the genome of Arabidopsis thaliana, which has also become the main plant model for the study of RdDM. Polymerase IV transcribes siRNA precursors; siRNAs are subsequently associated with AGO4 proteins and guide methylation enzymes to the target sequences via complementarity with polymerase V transcripts.
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Epigenetic regulation of HLA class II genes and its modification during the lifetime
Lamborová, Věra ; Kotrbová - Kozak, Anna Katarzyna (advisor) ; Černý, Jan (referee)
Background: The major histocompatibility complex (MHC) molecules play an important role in the immune response regulation and in the maintenance of the immune homeostasis. Regulation of their expression is therefore a key factor influencing the adaptive immune response. DNA methylation of gene regulatory regions is one of the mechanisms of gene expression control that affects the accessibility of DNA to transcription factors. Ageing is connected with changes in DNA methylation and increased predisposition to autoimmune diseases in older age could be associated with changes in MHC class II genes methylation. Aims: The aim of this diploma thesis is to analyze the methylation profile of DQA1 and DQB1 genes regulatory regions and to compare its differences between the generations and between individual alleles. The next aim is to compare DQA1 mRNA expression between the generations and between single alleles. Methods: DNA and RNA were isolated from blood of three age group donors. DNA was converted by the bisulfite treatment and regulatory regions of HLA class II genes were amplified and cloned into bacteria. Positive clones were sequenced and then analyzed. RNA was reverse transcribed and its expression level was determined by real-time PCR. Results: Statistically significant differences were found by...
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The study of epigenetic regulation of gene HLA II. Clas within family relationships
Chmel, Martin ; Černá, Marie (advisor) ; Urbanová, Jana (referee)
Introduction: At our post-genomic era the studies of epigenetic regulation constitutes one of the tools for understanding the function of genes. Epigenetic regulation can directly control the temporal and spatial gene activity or silencing. The molecular basis of these regulations are DNA bases modifications, chromatin remodeling and RNA interference. At the same time, these mechanisms have a special way of transferring genetic information to subsequent generations called epigenetic inheritance. It has been proven epigenetic deregulation of certain genes as cause for many disease. For this reason, the study of epigenome HLA genes seems particularly important because these genes play a fundamental role in regulating the immune system. Aims: The aim of this work is to create a description of epigenetic modifications within families. It is an analysis of histone modifications and DNA methylation in the promoter region of the gene HLA DQA1. The aim was also to compare the differences in epigenetic modifications between alleles and compared the differences in these modifications between generations. The results will be compared with the analysis of the level of expression of the gene HLA DQA1. Methods: From collected peripheral blood of donors were isolated DNA, RNA, and leukocytes. DNA was used for...
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Molecular genetic and biochemical studies of selected inherited metabolic disorders, development and applications of new methods
Mušálková, Dita ; Hřebíček, Martin (advisor) ; Adam, Tomáš (referee) ; Macek, Milan (referee)
Inherited metabolic disorders (IMD) form a diverse group of several hundred different diseases with a relatively high cumulative incidence (stated up to 1:600). They are associated with accumulation of the substrates and lack of the products in specific metabolic pathways, which is caused by deficiency of the enzyme or its activator, or dysfunction of the transport protein. However, the underlying cause is at the DNA level. The grounds for different phenotype manifestation in patients with the same genotype are often not known. During my work at the Institute of Inherited Metabolic Disorders, I designed several new methods for the research of IMD and applied them in the patients and their families. I created procedures for the isolation of lysosomal membranes that are used for the research of lysosomal storage disorders and general properties of lysosomes. Next, I introduced several novel assays for determination of the X-inactivation ratio, which led to a significant increase of informative women. Nowadays, we use these methods in heterozygous women with X-linked diseases in order to study the influence of X-inactivation on the manifestation of the diseases. The cases of a girl with mucopolysaccharidosis type II, a girl with OTC deficiency and a family with the mutation in HPRT1 gene are described...
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Epigenetické reprogramování u rostlin a živočichů
Tomanová, Markéta
Organisms have to cope almost daily with the activity of transposable elements which can cause negative effects in them thanks to their ability of transposition. The activity of transposons is regulated in normal conditions. From the point of view of their potential harmful activity, the most critical phase is the period of gametes formation and embryogenesis when the process called epigenetic reprogramming occures. It means that the epigenetic information (especially DNA mehylation) is deleted and than re-estabilished which is the esential process for cell diferentiation and tissue formation. During mentioned process of epigenetic reprogramming transposable elements become active which is the reason why this phase of the development is labeled as critical. This happenes especially in critical phases of their development. This work is focused to DNA methylation in transposons which was probably evolved as a sort of defense against their possible harmful effects. Processes wchich occure in reproductive cells are also described. Every mentioned processes are different in plant and animal cells. However, they are similar in some aspects. These are also the subject of this work.
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