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Epigenetika u zvířat
Abramov, Dmytro
Epigenetics studies changes in the function of genes that do not affect the primary nucleotide sequence of the DNA strand. In recent years, significant progress has been made in the study of epigenetic mechanisms, and it has been shown that epigenetic modifications have an enhanced effect not only during growth and development, but also during the phase of active ageing. The functions of DNA methylation have been determined, histone modifications and changes in chromatin structure have been described in more detail, and the role of RNA regulation of gene expression in various organisms has been clarified. The main aim of this bachelor thesis was to summarize the fundamental knowledge of epigenetic processes in animal organisms with a focus on mammalian laboratory models. Also in this literature review the focus was specifically on epigenetic changes in mammalian gamete and embryo development, epigenetics of animal health and epigenetic mechanisms of aging. In addition, processes that influence the animal breeding process were also described.
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Investigation of changes in epigenetic modofications in rat brain induced by morphine treatment
Hronová, Anna ; Novotný, Jiří (advisor) ; Roubalová, Lenka (referee)
This study addressed the impact of varying lengths of abstinence periods on the epitranscriptomic modification of m6 A and the enzymes involved in this modification as well as on transcription factors in the brains of morphine-dependent rats. The methods used included a colorimetric kit to determine m6 A levels and Western blotting to quantify the levels of enzymes and transcription factors. The results showed that different lengths of morphine abstinence did not have a significant effect on m6 A modification, suggesting that this pathway was likely not influenced by morphine abstinence. However, significant changes were observed in the levels of enzymes involved in the regulation of m6 A, which were localized and time-specific, without a clear trend. Examination of transcriptional regulators ∆FosB and MeCP2 also revealed significant changes only in certain parts of the brain and at specific times, but without a clear trend in changes in levels. The outcome of this study is that the dynamics of transcriptional regulators, N6 -methyl-adenosine, and enzymes involved in m6 A modification are localized and time-specific, opening new questions regarding the mechanisms that govern neurobiological processes during the abstinence period.
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The role of epigenetic mechanisms in the development of drug dependence
Durdilová, Marie ; Novotný, Jiří (advisor) ; Janoušková, Alena (referee)
The abuse of addictive substances is widely spread and carries numerous negative impacts, both on individuals and their surroundings. Some substances can lead to addiction after just a few doses, while for others, it may be a more prolonged process. However, the result is generally similar, with the prioritization of the drug or activity becoming the individual's main focus in life. This shift in priorities is linked to increased dopamine production due to the substance's effects, and the modulation of reward circuits in the brain. Changes in the connectivity and excitability of neurons in the mesolimbic and mesocorticolimbic dopamine systems lead to the development and maintenance of addiction. These neuronal changes are maintained in the body through epigenetic remodeling of chromatin. The pattern of epigenetic modifications, characteristic for a specific type of abused substance, can be passed on to the next generation, thereby increasing the potential for addiction development in offspring. Research on epigenetic modifications associated with addiction provides us with a deeper understanding of the neurophysiological changes accompanying drug addiction. At the same time, it raises the question of further treatment possibilities for drug addiction by targeting the epigenetic modifications that...
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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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Fungal metabolism modulation by plant substances
Sedláková, Vendula ; Čmoková, Adéla (advisor) ; Kolařík, Miroslav (referee)
Phytochemicals are bioactive substances by which plants affect organisms in their vicinity. Fungi often respond to their presence by metabolism alternation, which is manifested by the production of secondary metabolites, an increase in biomass or the regulation of virulence. These changes can be caused by phytochemicals (e.g. curcumin, EGCG) with abilities to modulate epigenetic information. The first half of the work is devoted to mechanisms of epigenetic modification (e.g. methylation, histone modification), which were studied in fungi. The second half summarizes studies focused on phytochemicals, in which the ability to modify epigenetic information in eukaryotic organisms was observed. The bachelor's thesis thus brings valuable knowledge about the possibility of modifying fungal metabolism by phytochemicals, which are often waste products of industry. Information summarized in this work can have a significant impact on improving biotechnological processes, where there is an effort to increase biomass yield or induce the production of secondary metabolites in cases where their production is normally suppressed. Key words: secondary metabolites, epigenetics, epigenetic modification, phytochemicals, filamentous fungi
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Programmed DNA elimination in animals
Janáková, Šárka ; Reifová, Radka (advisor) ; Choleva, Lukáš (referee)
Programmed DNA elimination (PDE) is a process in which a part of genetic information is eliminated from the organisms genome. It can be found be found in both plants and animals. There is a difference in the genetic inormation eliminated depending on the species. There are some organisms that eliminate only parts of their chromosomes, others that eliminate whole chromosomes and in hybrid organisms one whole parental genome is eliminated. In somatic cells PDE usually takes place during early embryogenesis. If the genome being eliminated comes from the germline cells, PDE takes place during gametogenesis. The function and mechanisms of PDE differs inbetween the species. It is most often connected with soma and germ cell differentiation, sex determination in animals and haploid gamete production in hybrid species. Mechanisms frequently include epigenetic modifications of DNA destined for elimination or production of micronuclei (MN) with the eliminated DNA inside. This work summarizes these functions and mechanisms and provides examples. Key words: programmed DNA elimination, chromatin diminution, chromosomal elimination, hybridogenesis, micronuclei, epigenetic modifications, Germ1, GRC
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Multifunctional protein CTCF and its role in regulation of gene expression
Pokorná, Linda ; Vacík, Tomáš (advisor) ; Vopálenský, Václav (referee)
CTCF is a ubiquitously expressed nuclear protein that binds to DNA through its central zinc finger domain. Thousands of CTCF binding sites have been identified throughout the human genome at gene promoters, in intergenic regions or in non-coding sequences. CTCF can function either as a positive or as a negative regulator of gene expression and is also involved in creating and maintaining long-range chromosomal interactions. Various developmentally important genes have been shown to be regulated by CTCF and its malfunction is frequently associated with developmental defects or diseases. CTCF undergoes various posttranslational modifications such as phosphorylation or SUMOylation which also affect its function in the regulation of gene expression. Keywords: CTCF, three dimensional genome, cohesin, regulation of gene expression, insulation, HOX genes
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Transgenerational Epigenetic Inheritance in Mammals
Dostálová, Veronika ; Švorcová, Jana (advisor) ; Markoš, Anton (referee)
Transgenerational epigenetic inheritance in mamals is a widely discussed topic in today's biology. Epigenetic modifications are molecules that play a crucial role in regulation of gene transcription. Epigenetic modifications regulate another epigenetic modification's establishment. The extrinsic and the intrinsic cellular or organismal environment is involved within the establishment of epigenetic state. The molecules involved in epigenetic processes are able to regulate gene transcription in reaction to the environment and therefore these molecules partly shape the phenotype. Most importantly, epigenetic processes are affected by cellular or organismal history. A question emerges: Are these molecules able to transfer information through germline to subsequent generations? Does transgenerational epigenetic inheritance in mammals exist? Experimental data show it is so. What consequences this can mean in our understanding of evolution? Powered by TCPDF (www.tcpdf.org)
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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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