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Eucaryotic cells systems and their biotechnologycal applications
Porubiaková, Otília ; Obruča, Stanislav (referee) ; Vorlíčková, Michaela (referee) ; Brázda, Václav (advisor)
The submitted dissertation is divided into several parts. The first part deals with the interactions of the p53 protein and its isoforms with different potential DNA substrates under different experimental conditions. These are predominantly DNA and its non-canonical structural motifs, such as G-quadruplexes or cruciform structures, whose interactions have been studied in yeast isogenic systems or by in vitro methods. The seconds part deals with the bioinformatic analysis of the mentioned secondary DNA structures in different organismal groups, and the result is a set of publications that show their non-random distribution in the genome and their relationship with regulation. The last part of the work contains unpublished results, including the results of testing the effect of natural and synthetic substances on aging in model human cells.
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Infuence of natural and synthetic G4-ligands to p53 transactivatio
Perná, Kristýna ; Smetana, Jan (referee) ; Brázda, Václav (advisor)
Secondary DNA structures, such as G-quadruplexes, occur in the promoters of human genes. Dysfunctions of these quadruplex structures have been observed in several cases of cancer, and therefore these structures are the subject of research for the design of new anticancer drugs. The p53 protein is an important regulatory protein in the process of cell cycle control and DNA repair. Mutations in the gene encoding this protein occur in more than 50 % of cancer cases. In this thesis, the influence of natural ligands binding to G-quadruplexes on the binding and activity of the p53 protein was investigated. The theoretical part of the thesis describes the structure and binding properties of p53 protein, the structure and role of G-quadruplexes and describes selected G4-ligands occurring in food - curcumin, quercetin, berberine and ellagic acid. The aim of the experimental part of this thesis was to determine the effect of these substances on the transactivation activity of the p53 protein in vivo based on their interaction with G-quadruplexes using yeast isogenic systems. The interaction between selected G-quadruplex structures and ligands was first verified in vitro using the ThT assay and circular dichroism.
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Analyses of inverted repeats localization in bacterial genomes
Šedý, Michal ; Zemanová, Jana (referee) ; Brázda, Václav (advisor)
Inverted repeats (IR) are common part of DNA of all living prokaryotic and eukaryotic organisms. Inverted repeats plays an important role in the regulation of basics cells processes. They are responsible for formation of cruciform structures. Inverted repeats also cause genomic instability and can be a source of numerous mutations. Cruciform structures can be recognized by DNA-binding proteins and can also act as a transcriptional regulators. Using the Palindrome Analyser tool, the frequency of IR and localization of inverted repeats in bacterial genomes was analyzed. The frequency of IR across the bacterial genome is variable. The frequency of short inverted repeats shows an approximately quadratic dependence on the %GC content in the genome with a minimum of about 50% of GC content. The localization of inverted repeats with respect to “annotated features” show a non-random distribution. The frequency of IR for most features is higher “outside” than “inside”.
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Optimization of p53 mutant protein isolation and its DNA binding properties
Osadchuk, Olha ; Zemanová, Jana (referee) ; Brázda, Václav (advisor)
Protein p53 je jednou z nejdůležitějších molekul v lidském těle. P53 reguluje celou řadu procesů v buňce, jako je například oprava DNA, buněčný cyklus nebo indukce apoptózy. Protein p53 je známý i jako „strážce genomu“. DNA vazebné schopnosti proteinu p53 jsou důležité pro normální vývoj a růst buňky. Mutace genu pro p53 mohou vést ke ztrátě jeho DNA vazebných vlastností a funkce nádorového supresoru, což muže způsobit rozvoj rakoviny. Teoretická část této diplomové práce je zaměřena na popis vlastností, funkce a mechanismus aktivace proteinu p53 a popis lokálních sekundárních struktur DNA. Hlavním cílem experimentální části byla produkce čtyř mutantních forem proteinů p53 a wild-type p53 proteinu a studium jejich vazebných vlastnosti s různými lokálními sekundárními strukturami DNA. Pomoci Gateway klonovacího systému byly připraveny čtyři expresní vektory, které byly použity pro produkci proteinů v bakteriálním expresním systému. Celkem byly úspěšně připraveny čtyři mutantní formy a wild-type p53 protein. Jejich vazebné vlastnosti byly studovány gelovou retardační analýzu. Výsledky naznačují různé DNA-vazebné vlastnosti wild-type p53 a studovaných mutantních forem tohoto proteinu. Všechny mutantní proteiny ztratily schopnost sekvenčně specificky vázat DNA, zatímco nespecifická interakce s DNA byla pozorována u tří ze čtyř mutantních forem. Jeden ze studovaných mutantních proteinů se vázal jenom na superhelikální formu DNA.
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Preparation and expression of p53 protein isoforms using the GATEWAY expression system
Wikarská, Monika ; Hrstka, Miroslav (referee) ; Brázda, Václav (advisor)
The TP53 gene can express protein p53 and 11 another isoform proteins N- and/or C-terminally truncated by using two promoters and alternative splicing. The p53 isoforms are found in both healthy and tumorous tissues, and are intensively studied in relation to cancer diagnosis, prognosis and treatment. In this work, the p53 isoforms were subcloned into expression vectors by LR reaction adapted from Gateway cloning system. The expression vectors were designed for protein production by bacteria E. coli strain BL-21. The constructs containing p53 isoforms were encoded together with two fusion proteins, glutathione-S-transferase and polyhistidine tag under the control of the same promotor for the affinity chromatography protein isolation. All the clones underwent Sanger sequencing for verification after homologous recombination. Sequencing confirmed the accuracy of the subcloned isoforms p53, 133p53, 160p53, p53 and 160p53 into an expression vector pDEST15-N6xHis-GST-GW-DEST. Protein 160p53 was expressed in BL-21 and isolated using both HIS and GST tag interacion. Isolation using HIS tag yielded in a higher protein concentration then the isolation mediated by the interaction of the glutathione-S-transferase.
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Preparation of constructs for protein isolation and its testing
Osadchuk, Olha ; Kostovová, Iveta (referee) ; Brázda, Václav (advisor)
This study is focused on describing of recombinant protein production. Protein p53 was chosen, as one of the most important tumor suppressor proteins, for studying this issue. The p53 protein is responsible for the gene regulation, control of cell cycle and DNA replication. P53 is the most mutated gene in human cancer. Several point mutations of p53 protein was chosen for work with. The theoretical part describes main properties of protein, expression systems, Gateway cloning system and methods of protein purification. In the experimental part are described the procedures of preparing of the expression vectors by Gateway technology, cell transformation and DNA plasmid isolation. Using cloning technology were prepared three expression clones, they were transformed into competent cells and after was done DNA isolation.
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P53 protein isoforms production and purification in the bacterial expression system
Vadovičová, Natália ; Obruča, Stanislav (referee) ; Brázda, Václav (advisor)
Apart from the p53 protein, the TP53 tumor-suppressor gene is expressed as another eleven protein isoforms with the use of alternative splicing, alternative promotors and alternative translational initiation sites. Abnormal expression of these isoforms has been observed in tumor tissues. The binding properties as well as the biological functions are also modulated, due to sequential and therefore structural differences from the p53 protein. p53 is regulated by these isoforms in both suppressive and supportive manner. Explanation of the p53 isoform regulation mechanism in cells could lead to desired alternative splicing of the chosen isoforms, and modulation of isoform expression could be used in cancer treatment based on p53 therapy. Basic information about p53 protein is summarised in the theoretical part of this master thesis, supplemented with recent advances in the field of p53 isoforms, as well as the Gateway cloning method. The main goal of the experimental part was p53 isoform production in a bacterial expression system. Prior to the protein production, DNA sequences coding twelve p53 isoforms were prepared using PCR and Gateway cloning. In total, twelve entry clones and eight expression clones were prepared by cloning the isoforms’ sequences. After the protein production and purification, the detection using SDS-PAGE and Western Blotting was performed with five p53 protein isoforms: p53, 40p53, 40p53 and 40p53. DNA binding properties of p53 protein isoforms will be tested in subsequent research.
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Detection of Transcription Factor Binding Sites
Hlávka, Ondřej ; Vogel, Ivan (referee) ; Martínek, Tomáš (advisor)
Nowadays, it is very important to study gene expression mechanism in molecular biology. Gene expression is also regulated by sequence specific transcription factors which binds to regulatory regions of the genes. Searching for this specific sequences can be very problematic because transcription factor binding sites can be very degenerative. There are several possible methods that can be aplied to this problem. First part of this paper describes few algorithms for transcription binding sites search. Second part contains design and implementation of algorithm for searching binding sites of transcription factor p53.
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Prediction of p53 Protein Binding Sites
Radakovič, Jozef ; Vogel, Ivan (referee) ; Martínek, Tomáš (advisor)
Protein p53 which is encoded by gene TP53 plays crucial role in cell cycle as a regulator of transcription of genes in cases when cell is under stress. Therefore p53 acts like tumor suppressor. Understanding the pathway of p53 regulation as well as predicting its binding sites on p53 regulated genes is one of the major concerns of modern research in genetics and bioinformatics. In first part of this project we aim to introduce basics from molecular biology to better understand the p53 protein pathway in gene transcription and introduction to analysis of prediction of p53 binding sites. Second part is about implementation and testing of tool which would be able to predict transcription factor binding sites for protein p53.
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