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Studies towards biological function of ubiquitin E3 ligase Rnf121 in vivo and in vitro
Škarabellová, Kateřina ; Sedláček, Radislav (advisor) ; Čermák, Lukáš (referee)
Although the RING finger protein 121 (RNF121) is a highly conserved E3 ubiquitin ligase from Caenorhabditis elegans to human, its function is poorly understood and in higher eukaryotes it has been studied only at in vitro level. RNF121 has been described to have various functions: i) it was ascribed to function as a broad regulator of NF-κB activation, ii) it was shown to control intracellular trafficking of various membrane proteins, and iii) its downregulation leads to apoptosis. Moreover, RNF121 might have a role in cancer as its expression was found to be 16.4-fold higher in patients suffering from Barrett esophagus (precancerous lesion of esophageal adenocarcinoma) and was even more increased in esophageal adenocarcinoma comparing to healthy population. In addition, RNF121 gene is localized in the candidate region containing breast cancer susceptibility genes. To gain insight into physiological functions of RNF121, Rnf121 knockout mice (Rnf121tm1b(EUCOMM)Hmgu ) were generated in the Czech Centre for Phenogenomics and further studied in our laboratory. Rnf121+ /- intercross breedings showed a prenatal lethal phenotype of Rnf121-/- embryos, which were dying prior embryonic day (E) 11.5. Preliminary experiments carried out in our laboratory showed numerous vascular defects in null mutant embryo,...
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Posttranslational modifications affecting function of nuclear localization signal
Šebrle, Erik ; Sedláček, Radislav (advisor) ; Venit, Tomáš (referee)
Transport of proteins to the nucleus through a nuclear envelope is controlled mostly via nuclear localization signal (NLS). Nuclear localization signal is rich in positively charged amino acids arginine and lysine. It was observed that activity of this NLS could be regulated through a phosphorylation of serine in its close proximity. Either a phosphorylation of serine or phosphomimetic changes of these "presequences" could represent an important mechanism regulating a localization of protein in cells in relation to a cellular activation. In our laboratory was identified protein - Fragile X mental retardation syndrome 1 neighbor (Fmr1nb), whose cellular localization could be driven by this posttranslational modification.
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Postranslation modifications affecting function of nuclear localization signal
Šebrle, Erik ; Sedláček, Radislav (advisor) ; Venit, Tomáš (referee)
Transport of proteins to the nucleus through a nuclear envelope is controlled mostly via nuclear localization signal (NLS). Nuclear localization signal is rich in positively charged amino acids arginine and lysine. It was observed that activity of this NLS could be regulated through a phosphorylation of serine in its close proximity. Either a phosphorylation of serine or phosphomimetic changes of these "presequences" could represent an important mechanism regulating a localization of protein in cells in relation to a cellular activation. In our laboratory was identified protein - Fragile X mental retardation syndrome 1 neighbor (Fmr1nb), whose cellular localization could be driven by this posttranslational modification.
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Generation and analysis of double deficient transgenic mice for kallikrein-related peptidase 5 and kallikrein-related peptidase 14
Hanečková, Radmila ; Sedláček, Radislav (advisor) ; Fulková, Helena (referee)
Kallikrein-related peptidases (KLKs) constitute a highly conserved serine protease family. Based on in vitro experiments, KLKs are predicted to play an important role in a number of physiolog- ical and pathophysiological processes. However, their role in vivo remains not fully understood, partially due to a lack of suitable animal models. In this work, we aim to prepare a KLK5 and KLK14 double-deficient mouse model. Both KLK5 and KLK14 were proposed to be involved in epidermal proteolytic networks critical for maintaining skin homeostasis. However, both KLK5 and KLK14 single-deficient mouse models show minimal or no phenotype, likely due to similar substrate specificity resulting in functional compensation. Double-deficient mice cannot be easily obtained by crossing due to localization of the Klk5 and Klk14 genes within the same locus on chromosome 7. We report that KLK5 and KLK14 double-deficient mice were success- fully generated, mediated by transcription activator-like effector nucleases (TALENs) targeting Klk14 by microinjection of TALEN mRNA into KLK5-deficient zygotes. Furthermore, we show that KLK5 and KLK14 double-deficient mice are viable and fertile. We believe that these novel mouse models may serve as a useful experimental tool to study KLK5 and KLK14 in vivo.
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Generation of conditional animal mutants to study gene function in vivo
Herrmannová, Pavlína ; Sedláček, Radislav (advisor) ; Novák, Josef (referee)
Conditional gene targeting allows spatial and temporal control of genetic modifications and is used to study gene functions in specific tissues or cell types. Gene targeting may lead to inactivation of the gene by insertions or deletions. Conditional gene targeting uses various methods for generation of transgenic mutant animals, such as technology of targeted disruption of gene using embryonic stem cells, methodology based on bacterial artificial chromosomes, or a new revolutionary technology of targeted disruption of genes using programmable nucleases, which is rapidly evolving and seems to be more efficient and cheaper method for conditional gene targeting. The aim of this work is to overview methods and technologies for generation conditional animal models, and overview conditional recombination systems with emphasis on inducible systems, and also provides a summary of the main international resources for rodent mutagenesis. Key words: transgenic animal model, gene, targeting, conditional allele
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Genome editing using programmable endonucleases
Hanečková, Radmila ; Sedláček, Radislav (advisor) ; Sýkora, Michal (referee)
Programmable endonucleases are engineered proteins that recognize specific nucleotide sequences and that are capable of introducing double-strand breaks within these sequences. Zinc-finger nucleases have been used extensively as a tool in genome editing, the practice of introducing changes into genomes of cell lines or whole organisms as a way to study gene function. Recently, new types of programmable endonucleases have emerged in the form of transcription activator like effector (TALE) nucleases and the CRISPR/Cas system. The types differ in respect to their mechanism of function, accessibility, selectivity, frequency of off-target cleavage and cytotoxic effects. Here, we compare zinc-finger nucleases, TALENs and the CRISPR/Cas system and explore their current and possible future applications in a broad spectrum of research ranging from developing genetically modified organisms to gene therapy. Powered by TCPDF (www.tcpdf.org)
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Generation and analysis of mutant mouse models to study pathophysiological roles of KLK5 and KLK7 in epidermis
Kašpárek, Petr ; Sedláček, Radislav (advisor) ; Stopka, Pavel (referee) ; Machoň, Ondřej (referee)
Kallikrein-related peptidases (KLKs) constitute a family of closely related serine proteases encoded by genes clustered in one chromosomal locus. KLKs are widely expressed in a variety of tissues and numerous in vitro experiments suggest their important roles in many physiological and pathological processes. However, the biological roles of KLKs in vivo are often obscured mainly due to unavailability of suitable animal models. Although gene deficient mouse models were generated for several KLK genes, they had limited use for understanding the roles of individual proteases in the complex environment in vivo. One of the main obstacles which hampers in vivo analysis is partial functional overlap between some KLKs. This makes traditional single-gene deficient animal models an inadequate tool to address the biological impact of the gene deficiency as compensatory mechanisms often result in a lack of phenotype. In this work, we used the transcription activator-like effector nuclease (TALEN) technology to generate several novel mutant mouse models to study the complex KLK proteolytic pathways and their roles in healthy organism and in disease. We prepared a novel mouse model for Netherton syndrome (NS), an autosomal recessive skin disorder caused by mutation in the gene SPINK5, which encodes the KLK-inhibitor...
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Influence of extracellular matrix environment on gene expression in liver myofibriloblasts
Jiroutová, Alena ; Kanta, Jiří (advisor) ; Ehrmann, Jiří (referee) ; Sedláček, Radislav (referee)
Influence of extracellular matrix environment on gene expression in liver myofibroblast (summary) Hepatic stellate cells (HSC) and liver myofibroblasts (MF) are two cell populations most likely responsible for the synthesis of majority of connective tissue components in fibrotic liver. They differ in their origin and location in the liver, and in the spectrum of genes they express. HSC are located in Disse spaces of normal rat liver around the sinusoids, in fibrotic liver they become activated, proliferate and they undergo transdifferentiation into myofibroblast-like cells. Myofibroblasts are heterogenous cell population that consists at least of portal pMF, septal sMF and interface iMF. pMF, which are adjacent to bile duct epithelia, may be a mediator of billiary type fibrosis. sMF are located within and along the collagenous septum in cirrhotic liver. Little is known about the expression of genes involved in connective tissue metabolism in MF cultured in fibrin or collagen gels that more closely resemble natural cell environment. Fibrin is deposited in liver at sites of injury and collagen type I forms a substantial part of fibrotic septa. In our study oligo cDNA array analysis was used to determine gene expression in quiescent HSC, activated HSC and MF isolated from both normal and CCl4-cirrhotic liver....
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Characterization of the role of SPINK 6 in the epidermis using transgenic models
Buryová, Halka ; Sedláček, Radislav (advisor) ; Entlicher, Gustav (referee)
Epidermal homeostasis, including proper turnover of keratinocytes, plays important role in the barrier function and serine proteases and their inhibitors are the key players. Activated proteases cleave desmosomes in uppermost layer and thus shed the cells from the epidermal surface. Therefore the serine protease inhibitors are secreted in lower epidermal layers to prevent premature activation of proteases and consequent disruption of epidermal barrier. The most studied inhibitors in epidermis belong to Serine proteases inhibitors Kazal-type family (SPINK). This diploma thesis is aimed to investigate function of murine SPINK6 in epidermal compartment in vivo. To achieve this, the transgenic mice overexpressing mSPINK6 under modified human involucrin promoter was generated. Two of five transgenic lines exhibited higher expression of mSPINK6 at mRNA and protein levels. The mSPINK6 transgenic mice are viable with no apparent phenotype. The small but in most cases not significant differences were observed on microscopic level among mSPINK6 transgenic and wild type animals In conclusion, this work showed that mSPINK6 does not play major role in skin homeostasis but gains significant importance under specific challenges of epidermal barrier. Therefore mSPINK6 transgenic mice, in combination with other deletion or...
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Generation of transgenic mouse model to study biological role of KLK5 in epidermis
Kašpárek, Petr ; Sedláček, Radislav (advisor) ; Fafílek, Bohumil (referee)
A number of studies provide strong evidence that KLK5 is one of the most important serine proteases in the epidermis and is involved in processes such as desquamation, processing of antimicrobial peptides or induction of inflammatory reaction. The role of KLK5 has been deduced from in vitro experiments and thus its functions should be verified in vivo. This work aimed to develop a specific tissue targeting strategy to study the role of murine kallikreins in the epidermal compartment in vivo and to generate a transgenic model overexpressing mKlk5 in the mouse epidermis. Using the modified promoter of human involucrin, transgenic mice expressing the fluorescent marker, tdTomato, were generated in the first step. This transgenic reporter mouse showed specific targeting pattern of the reporter in the upper epidermal layers and, thus, the modified involucrin promoter could be employed for targeting further gene of interest in the differentiated epidermal compartment. In the second step transgenic mouse lines expressing murine kallikrein 5 were successfully generated. Among them two lines exhibited approximately 6-9 fold overexpression at the mRNA and protein levels, however it appeared that the immature protease was not activated under normal healthy conditions. Therefore two models of epidermal...
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