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Sequences forming G-quadruplexes in the amyloid beta precursor human gene and its homologues
Stránská, Anna ; Šedrlová, Zuzana (referee) ; Brázda, Václav (advisor)
The APP gene encodes the transmembrane protein amyloid beta precursor, which is expressed in many cell types, including neurons. Its functions have not yet been fully described, but it is clear that it is being cleaved before being exported to the extracellular space. It is degraded by various degradation pathways also undergoes homodimerization, which can produce particles with protective neuronal function as well as fragments that are toxic and cause nerve cell death. The formation of harmful amyloid beta plaques and their accumulation among neurons in the brain is closely linked to the onset and progression of Alzheimer's disease, a neurodegenerative brain disease manifested by death and loss of neurons, which leads to dementia, i.e. loss of cognitive functions. There is currently a lot of research that deals with the links between neurodegenerative diseases and the occurrence of G-quadruplexes in genes that are involved in disease manifestations. G-quadruplexes are non-canonical DNA and RNA nucleic acid secondary structures that arise in guanine-rich regions. They are important mainly in terms of their connection with biological processes such as the regulation of gene expression in genes and mainly in oncogenes because they occur in important regions of the gene such as the promoter. It is possible to stabilize them with small molecules, and it is this ability that is used in research into the therapeutic treatment of various diseases. A bioinformatics analysis of both the human gene and 346 other gene homologs was performed to determine the importance of G-quadruplexes localization and conservation in the human APP gene. For this purpose, the G4Hunter program was used, which provided information about the found sequences with the potential to form a G-quadruplex, such as their location or G4Hunter score. In vitro analysis was performed using thioflavin T reagent, which tested the ability of the found sequences to form G-quadruplexes under physiological conditions. The results confirmed the presence and evolutionary importance of G-quadruplexes found in the APP gene of Homo sapiens and their ability to assemble into quadruplex structures in the presence of salts such as sodium and potassium.
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Sequences forming G-quadruplexes in the amyloid beta precursor human gene and its homologues
Stránská, Anna ; Šedrlová, Zuzana (referee) ; Brázda, Václav (advisor)
The APP gene encodes the transmembrane protein amyloid beta precursor, which is expressed in many cell types, including neurons. Its functions have not yet been fully described, but it is clear that it is being cleaved before being exported to the extracellular space. It is degraded by various degradation pathways also undergoes homodimerization, which can produce particles with protective neuronal function as well as fragments that are toxic and cause nerve cell death. The formation of harmful amyloid beta plaques and their accumulation among neurons in the brain is closely linked to the onset and progression of Alzheimer's disease, a neurodegenerative brain disease manifested by death and loss of neurons, which leads to dementia, i.e. loss of cognitive functions. There is currently a lot of research that deals with the links between neurodegenerative diseases and the occurrence of G-quadruplexes in genes that are involved in disease manifestations. G-quadruplexes are non-canonical DNA and RNA nucleic acid secondary structures that arise in guanine-rich regions. They are important mainly in terms of their connection with biological processes such as the regulation of gene expression in genes and mainly in oncogenes because they occur in important regions of the gene such as the promoter. It is possible to stabilize them with small molecules, and it is this ability that is used in research into the therapeutic treatment of various diseases. A bioinformatics analysis of both the human gene and 346 other gene homologs was performed to determine the importance of G-quadruplexes localization and conservation in the human APP gene. For this purpose, the G4Hunter program was used, which provided information about the found sequences with the potential to form a G-quadruplex, such as their location or G4Hunter score. In vitro analysis was performed using thioflavin T reagent, which tested the ability of the found sequences to form G-quadruplexes under physiological conditions. The results confirmed the presence and evolutionary importance of G-quadruplexes found in the APP gene of Homo sapiens and their ability to assemble into quadruplex structures in the presence of salts such as sodium and potassium.
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RNA secondary structure conservation identification module for rPredictor
Pešek, Jan ; Hoksza, David (advisor) ; Škoda, Petr (referee)
The issue of comparing ribosomal RNA secondary structures is currently an open research problem. Goal of this work is to design and implement program comparing so called mutual conservancy of a group of rRNA secondary structures. This program is included as a new module of an existing system called rPredictor consisting of the structure database and an algorithm that predicts these structures. This thesis covers an introduction into the problem of secondary structures conservancy identification and summarizes known approaches towards the problem. The result of this work is a stand alone program for the secondary structure comparison and also a new analytic module of the rPredictor system, where the secondary structure comparison program can be used for comparison of the structures from the rPredictor database. Powered by TCPDF (www.tcpdf.org)
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RNA secondary structure visualization using existing structures
Eliáš, Richard ; Hoksza, David (advisor) ; Jelínek, Jan (referee)
Many research aim to RNA molecules and demand for tools enabling their analysis increased. First step is visual inspection of their secondary structure. In order to correctly lay out structure, the notion of optimal layout is required. However, this has never been formalized and is largely habitual. To tackle this problem we propose an algorithm capable of visualizing RNA structure using related one with known layout. Algorithm first converts both RNAs into a tree representation and using tree-edit-distance algorithm finds out the minimum number of operations to convert one structure into the other. All common motives are retained and the regions which differ are taken care of. Results show, that our algorithm is able to give good layouts even for relatively distant structures. It is well suited for visualization of homologous structures. Powered by TCPDF (www.tcpdf.org)
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RNA secondary structure conservation identification module for rPredictor
Pešek, Jan ; Hoksza, David (advisor) ; Škoda, Petr (referee)
The issue of comparing ribosomal RNA secondary structures is currently an open research problem. Goal of this work is to design and implement program comparing so called mutual conservancy of a group of rRNA secondary structures. This program is included as a new module of an existing system called rPredictor consisting of the structure database and an algorithm that predicts these structures. This thesis covers an introduction into the problem of secondary structures conservancy identification and summarizes known approaches towards the problem. The result of this work is a stand alone program for the secondary structure comparison and also a new analytic module of the rPredictor system, where the secondary structure comparison program can be used for comparison of the structures from the rPredictor database. Powered by TCPDF (www.tcpdf.org)
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Structure- and sequence-based identification of functionally important amino acids in a protein family
Peclinovská, Iveta ; Novotný, Marian (advisor) ; Pleskot, Roman (referee)
A group of small GTPases consist of over twenty protein families in the super class P-loop. It has a very diverse cell functions. Small GTPases regulate the formation of vesicular follicles, cytoskeleton and nuclear transport. They participate also on cell proliferation and signaling. The aim of my work is to find important amino acids that define family and distinguish each other. I focus on families Arf, Rab, Ran, Ras and Rho. At the Rho family I am also devoted to classes Rho, Rac and Cdc42. Amino acids are identified using bioinformatic programs selected Consurf and Sca5. The objective is also to test P2RANK specialized tool developed at the Charles University in Prague that predict ligand binding sites from protein structure in different families. Founding amino acids can have a big role in the functional divergence of individual families and classes of small GTPases and can be the basis for future study example for the proliferation of cancerous cells. 1.1 Keywords Powered by TCPDF (www.tcpdf.org)
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A comparison of SH3 domains' tyrosine phosporylation influence on their binding capacity
Tatárová, Zuzana ; Novotný, Marian (advisor) ; Kuthan, Martin (referee)
Understanding the impact of protein phosphorylation is very important for the formation of dynamic biological processes such as gene silencing, cell growth, differentiation or apoptosis. This work deals with the phosphorylation of a protein-interaction module known as SH3 domain and the influence of phosphorylation on its ligand-binding capacity. SH3 domain is a part of a large number of enzymes directly involved in signal transduction as well as adapter proteins without enzymatic activity. Many studies have shown the importance of tyrosine sites within SH3 domain in regulatory mechanisms of proteins by using either mutants that cannot be phosphorylated, mutants mimicking the negative charges created by phosphorylation or by evidence of in vivo phosphorylation. The work also includes bioinformatic analysis, which further expand our knowledge of SH3 phosphorylated proteins and confirms that phosphorylation of the tyrosine sites is conserved among proteins containing the SH3 domain.
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