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Mapping of regulatory elements within 5' region of the Disp3 locus
Oltová, Jana ; Bartůněk, Petr (advisor) ; Krásný, Libor (referee)
Dispatched 3 (Disp3), a thyroid hormone-regulated gene, is studied extensively in our laboratory. Phenotype of cells with overexpressed Disp3 and its expression pattern make it a perfect candidate for a molecular link between thyroid hormone action and cholesterol homeostasis in the brain. Moreover, we hypothesize that it might play a role in certain neurodegenerative disorders and brain tumours. This thesis is aimed at the process of regulation of this gene via thyroid hormone receptor (TR), specifically identification of responsive elements of the thyroid hormone receptor that are necessary for the regulation. Also, we searched for elements recognized by liver X receptor (LXR), as LXR binds to the same arrangement of repeats as TR and there are a number of genes regulated by both of them. We combined in silico analysis of the Disp3 locus with reporter luciferase assays. A cluster of six elements identified around the first exon with two of them being conserved among human and mice draw our attention. In order to analyze this sequence in more detail, reporter vectors of various truncations of 3 kb region around exon 1 were constructed and tested in reporter assays. Reporter assays did not reveal any substantial element activated by TR or LXR; on the other hand, region containing repressor element(s)...
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Regulation of gene expression by thyroid hormone receptors
Oltová, Jana ; Bartůněk, Petr (advisor) ; Fafílek, Bohumil (referee)
Hormones coordinate various processes in living organisms and their action is mediated either by cell membrane receptors or nuclear receptors. Thyroid hormones (THs) have prominent effects on the growth, development, and many aspects of metabolism, embryogenesis and early life. Their receptors (TRs) belong to the nuclear receptor superfamily, whose members function as ligand-activated transcription factors, and depending on the context, they can act both as activators or as inhibitors of transcription. Thyroid hormone receptors are encoded by two genes, TRα and TRβ, and by alternative splicing multiple isoforms are generated. The major form of TR binds to T3-response element as a heterodimer with retinoid X receptor (RXR). TRs are able to bind T3-response elements (TREs) independently of ligand occupancy. TREs contain two or more subsequent half-site sequences of AGGTCA, which are usually arranged as direct repeats with four nucleotide spacing (DR4). TH-responsive target genes are involved in a wide range of cellular pathways. Example of such gene is Disp3, which might link TH and cholesterol metabolism in certain cell types.
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The role of Kit ligands in hematopoiesis of Danio rerio
Oltová, Jana
Hematopoiesis is a precisely regulated process, dependent on the activity of hematopoietic cytokines and their receptors. Due to an extra round of whole genome duplication in teleost fish, two paralogs of many important genes, including some hematopoietic cytokines and their receptors, are present in the zebrafish (Danio rerio) genome. In this project, we have been investigating the role of zebrafish Kit ligands in hematopoiesis. Kit ligand is a pleiotropic cytokine, which is essential for vertebrate erythropoiesis; however, in zebrafish, no such role has been reported so far. To determine the function of zebrafish paralogs of Kit ligand (Kitlga and Kitlgb) in hematopoiesis, we performed in vivo and ex vivo gain- and loss-of-function experiments. Strikingly, we were the first to report the synergistic cooperation of zebrafish Kitlga with erythropoietin and dexamethasone, enabling the growth of kidney marrow-derived suspension cells and providing optimal conditions for the expansion of adult erythroid progenitors. We assume that by using different cytokine combinations, optimal conditions for the growth of other hematopoietic cell types can be established, and therefore, this new approach now available for the...
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The role of Kit ligands in hematopoiesis of Danio rerio
Oltová, Jana ; Bartůněk, Petr (advisor) ; Živný, Jan (referee) ; Divoký, Vladimír (referee)
Hematopoiesis is a precisely regulated process, dependent on the activity of hematopoietic cytokines and their receptors. Due to an extra round of whole genome duplication in teleost fish, two paralogs of many important genes, including some hematopoietic cytokines and their receptors, are present in the zebrafish (Danio rerio) genome. In this project, we have been investigating the role of zebrafish Kit ligands in hematopoiesis. Kit ligand is a pleiotropic cytokine, which is essential for vertebrate erythropoiesis; however, in zebrafish, no such role has been reported so far. To determine the function of zebrafish paralogs of Kit ligand (Kitlga and Kitlgb) in hematopoiesis, we performed in vivo and ex vivo gain- and loss-of-function experiments. Strikingly, we were the first to report the synergistic cooperation of zebrafish Kitlga with erythropoietin and dexamethasone, enabling the growth of kidney marrow-derived suspension cells and providing optimal conditions for the expansion of adult erythroid progenitors. We assume that by using different cytokine combinations, optimal conditions for the growth of other hematopoietic cell types can be established, and therefore, this new approach now available for the...
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Mapping of regulatory elements within 5' region of the Disp3 locus
Oltová, Jana ; Bartůněk, Petr (advisor) ; Krásný, Libor (referee)
Dispatched 3 (Disp3), a thyroid hormone-regulated gene, is studied extensively in our laboratory. Phenotype of cells with overexpressed Disp3 and its expression pattern make it a perfect candidate for a molecular link between thyroid hormone action and cholesterol homeostasis in the brain. Moreover, we hypothesize that it might play a role in certain neurodegenerative disorders and brain tumours. This thesis is aimed at the process of regulation of this gene via thyroid hormone receptor (TR), specifically identification of responsive elements of the thyroid hormone receptor that are necessary for the regulation. Also, we searched for elements recognized by liver X receptor (LXR), as LXR binds to the same arrangement of repeats as TR and there are a number of genes regulated by both of them. We combined in silico analysis of the Disp3 locus with reporter luciferase assays. A cluster of six elements identified around the first exon with two of them being conserved among human and mice draw our attention. In order to analyze this sequence in more detail, reporter vectors of various truncations of 3 kb region around exon 1 were constructed and tested in reporter assays. Reporter assays did not reveal any substantial element activated by TR or LXR; on the other hand, region containing repressor element(s)...
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Regulation of gene expression by thyroid hormone receptors
Oltová, Jana ; Fafílek, Bohumil (referee) ; Bartůněk, Petr (advisor)
Hormones coordinate various processes in living organisms and their action is mediated either by cell membrane receptors or nuclear receptors. Thyroid hormones (THs) have prominent effects on the growth, development, and many aspects of metabolism, embryogenesis and early life. Their receptors (TRs) belong to the nuclear receptor superfamily, whose members function as ligand-activated transcription factors, and depending on the context, they can act both as activators or as inhibitors of transcription. Thyroid hormone receptors are encoded by two genes, TRα and TRβ, and by alternative splicing multiple isoforms are generated. The major form of TR binds to T3-response element as a heterodimer with retinoid X receptor (RXR). TRs are able to bind T3-response elements (TREs) independently of ligand occupancy. TREs contain two or more subsequent half-site sequences of AGGTCA, which are usually arranged as direct repeats with four nucleotide spacing (DR4). TH-responsive target genes are involved in a wide range of cellular pathways. Example of such gene is Disp3, which might link TH and cholesterol metabolism in certain cell types.
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