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Development of new molecular tools for altering gene expression in Giardia intestinalis .
Horáčková, Vendula ; Doležal, Pavel (advisor) ; Horváthová, Lenka (referee)
Giardia intestinalis is a widespread intestinal parasite that causes diarrhea in human and other vertebrate hosts. Although, fully sequenced genome of G. intestinalis has been published, very little is known about the regulation of gene expression. Together with the tetraploid genome, this complicates the use of many common reverse genetics methods. The aim of this thesis was to develop new molecular tools that can be used to alter gene expression in G. intestinalis. For the purposes of this work, new vectors for tetracycline-inducible gene expression including T7 promoter and endogenous oct promoter were designed. Furthermore, cwp1 gene knock-out was created using CRISPR-Cas9 technology. In order to modify mechanisms of double strand break repair, expression of two key components of bacterial NHEJ pathway - LigD and Ku - was introduced into cells of G. intestinalis.
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The functional in vitro analysis of the BRCA1alternative splicing variants
Ševčík, Jan ; Kleibl, Zdeněk (advisor) ; Stopka, Tomáš (referee) ; Macůrek, Libor (referee)
BACKGROUND: The inactivation of the tumor suppressor gene BRCA1 is a predisposing factor for a breast/ovarian cancer development. Formation of cancer-specific alternative splicing variants with aberrant biological properties can represent additional mechanism decreasing the overall BRCA1 activity in DNA double strand break (DDSB) repair. In this study, we analyzed BRCA1 alternative splicing variants BRCA114-15 and 17-19 ascertained previously during the screening of high-risk breast cancer individuals. METHODS: We established a stable MCF-7 cell line-based model system for an in vitro analysis of BRCA1 variants. Using this system, we analyzed the impact of BRCA114-15 and 17-19 variants on DNA repair kinetics using comet assay and confocal immunomicroscopy. The capacity of DNA repair was assessed directly by an in vitro NHEJ assay and indirectly by a mitomycin C sensitivity test. The proliferation activities were determined by a clonogenic assay and growth curves. RESULTS: Overexpression of BRCA114-15 and 17-19 increases the endogenous level of DNA damage, slows down the DDSB repair, and decelerates the initial phase of radiation-induced foci formation and prolongs their persistence. Moreover, BRCA114-15 and 17-19 differentially influence the activity of HR and NHEJ and sensitivity of MCF-7 cells to ionizing...
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Mechanisms of origin of cryptic rearrangements in human chromosomes and its clinical associations
Šenkyřík, Pavel ; Šolc, Roman (advisor) ; Drábová, Jana (referee)
Chromosomal rearrangements are one of the processes which leads to formation of genetic disorders. Among the mechanisms that cause the rearrangements belong NAHR, NHEJ, FoSTeS and MMBIR. They generate rearrangements of many types and have different requirements for their realization. NAHR is recombination-based mechanism responsible for recurrent rearrangements and operates mainly in repetitive sequences. NHEJ is used for repair of double-strand breaks and generates non-recurrent rearrangements due to its error rate. FoSTeS and MMBIR are replication-based mechanisms able to make both complex rearrangements and less massive non-recurrent rearrangements. Architecture of DNA has influence on all above-mentioned mechanisms. Structures that affect course or effectivity of mechanisms are microhomologies, double-strand breaks, tandem repetitions, hairpins, and loops causing stalling of replication fork.
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The functional in vitro analysis of the BRCA1alternative splicing variants
Ševčík, Jan ; Kleibl, Zdeněk (advisor) ; Stopka, Tomáš (referee) ; Macůrek, Libor (referee)
BACKGROUND: The inactivation of the tumor suppressor gene BRCA1 is a predisposing factor for a breast/ovarian cancer development. Formation of cancer-specific alternative splicing variants with aberrant biological properties can represent additional mechanism decreasing the overall BRCA1 activity in DNA double strand break (DDSB) repair. In this study, we analyzed BRCA1 alternative splicing variants BRCA114-15 and 17-19 ascertained previously during the screening of high-risk breast cancer individuals. METHODS: We established a stable MCF-7 cell line-based model system for an in vitro analysis of BRCA1 variants. Using this system, we analyzed the impact of BRCA114-15 and 17-19 variants on DNA repair kinetics using comet assay and confocal immunomicroscopy. The capacity of DNA repair was assessed directly by an in vitro NHEJ assay and indirectly by a mitomycin C sensitivity test. The proliferation activities were determined by a clonogenic assay and growth curves. RESULTS: Overexpression of BRCA114-15 and 17-19 increases the endogenous level of DNA damage, slows down the DDSB repair, and decelerates the initial phase of radiation-induced foci formation and prolongs their persistence. Moreover, BRCA114-15 and 17-19 differentially influence the activity of HR and NHEJ and sensitivity of MCF-7 cells to ionizing...
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