National Repository of Grey Literature 110 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Delivery of genomes of nonenveloped DNA viruses into the cell nucleus
Bílková, Eva ; Forstová, Jitka (advisor) ; Hatáková, Ladislava (referee)
The majority of DNA viruses have to deliver their genome to the cell nucleus, which provi- des factors required for their replication and transcription. This work is focused on this proces of small nonenveloped DNA viruses. It describes delivery of the adenovirus, parvovirus, pa- pillomavirus and polyomavirus genomes into the cell nucleus. These viruses are endocyted by the cell and travel to the enveloped compartments. Viral particle undergoes changes afffected by surrounding environment and activity of cellular enzymes, which results in its escape from enveloped vesicle mediated by the viral proteins. Some viruses use direct interactions with cytos- keletal transport components for travelling to the cell nucleus. In most cases, viral DNA enters cell nucleus via nuclear pore complex, although the evidence of alternative mechanisms exists as well. This work focuses on early phases of the life cycle of the selected viruses and the nucleus targeting of their genomes. Understanding the mechanisms of viral DNA nuclear import may contribute to discovery of new anti-viral therapies.
Preparation of expression vectors and virus mutants for studies of the minor structural proteins of polyomaviruses.
Cibulka, Jakub ; Forstová, Jitka (advisor) ; Šroller, Vojtěch (referee)
Polyomaviruses are small non-enveloped DNA viruses infecting birds and mammals, including human. Their capsid consists of the major capsid protein, VP1, and two minor capsid proteins, VP2 and VP3. The VP2 and VP3 proteins are supposed to have an important function in the transport of viral genome into the cell nucleus, which is a key step to facilitate viral replication. VP2 and VP3 proteins of mouse polyomavirus and SV40 have an ability to bind and disrupt cellular membranes. This feature is believed to be involved in the transport of viral genome into the nucleus. Plasmids carrying genes of the minor capsid proteins of Merkel cell polyomavirus were prepared in order to produce and visualize these proteins in mammalian cells. These proteins are known to have very unusual sequences compared to other human polyomaviruses or related mouse polyomavirus. When produced alone, the minor capsid proteins of Merkel cell polyomavirus did not significantly interact with cellular membranes, unlike the minor proteins of the mouse polyomavirus. The second goal of this work was to prepare mouse polyomavirus mutants with deletion in hydrophobic domains of VP2 and VP3 proteins. These domains are likely responsible for the mentioned membrane interactions. Prepared mutants were non-infectious. The loss of infectivity was not...
Study of the assembly and budding of mouse mammary tumor virus MMTV
Hoboth, Peter ; Zábranský, Aleš (advisor) ; Forstová, Jitka (referee)
Mouse mammary tumor virus (MMTV) is a prototypical member of the Betaretrovirus genus characterized by the ability to preassemble viral particles in the cytoplasm of the host cells. Intracellularly preassembled particles are subsequently transported to the plasma membrane being enveloped by a lipid bilayer and released from the cell in the process referred to as budding. Retrovirus particle assembly is driven by the Gag polyprotein precursor, which is cleaved in the maturation process by virus-encoded protease to liberate multiple structural proteins. The matrix (MA), capsid (CA) and nucleocapsid (NC) protein domains that are common to all retroviruses and in the case of MMTV, also the noncanonical domains, pp21, p3, p8 and "n", located between MA and CA domain are present. The role of these specific domains remains undefined. The retroviral budding is stimulated by short peptide motifs, so-called late (L) domains, located within Gag sequence. These L domains mediate interactions with cellular proteins normally involved in the biogenesis of the multivesicular bodies and protein sorting. Three types of the L domains have been identified to date, with the consensus of the amino acid sequences (i) P(T/S)AP, (ii) YP(x)nL (where x represents any amino acid and n≤3) and (iii) PPxY. Disruption of the L domain...
Caveolae and caveosoms
Galica, Tomáš ; Černý, Jan (advisor) ; Forstová, Jitka (referee)
Caevolae are remarkably stable structures at the plasma membrane. They form specific domains distinct in lipid composition from the rest of plasma membrane. Many diverse functions are assigned to Caevolae. They play role in modulation of cellular surface, signalization and well regulated endocytosis. Caveosomes suppose to be large intracellular vesicular structures potentialy new membrane organels. They are derived from internalized caveolae. Tohether with caveolae they are proposed to form a separeted system of intracellular vesicles. However recent evidence suggests that caveolae can fuse with endosomes immediately after internalization. If this is true, then the system of vesicles derived from caveolae, including caveosomes, can be considered a regular component of endosomal system. Isolation of caveosomes from endosomes has been seen mainly in experiments where polyomavirus SV40 was used. Thus the question, if this isolation is not just a result of SV40 infection, arises. It has been shown recently that SV40 virus is capable of inducing caveosome-like structures even in the absence of caveolae. Consequently existence and properties of caveosomes are being questioned. The problem of high importance is the genesis of caveosomes and their existence in SV40 non-infected cells. In this thesis...
Interference of selected DNA viruses with apoptotic processes
Sauerová, Pavla ; Forstová, Jitka (advisor) ; Štěpánek, Luděk (referee)
This work is focused on selected DNA viruses and some of their mechanisms used for inhibition or induction of the apoptotic processes. The selected DNA viruses are Hepatitis B virus, polyomaviruses, papillomaviruses and herpesviruses. Viruses developed different strategies for fighting the host defense mechanism during their evolution. One of the host defense mechanisms that reacts against virus infection is apoptosis. In case of viruses we can observe the phenomenon of inhibition or induction of apoptosis (which both depend on the life cycle phase of the virus). The purpose of these "fighting" strategies is to ensure successful replication, virus releasing from the cell and finally to let it spread in an organism or among them. Some "fighting" strategies are similar e.g. targeting and manipulation on p53 oncosupresor level or production of Bcl-2 homologs; other strategies are very specific. Certain viruses have mechanisms which allow them to survive in a host organism for a long time.
Promyelocytic leukemia protein function in normal, tumor and senescent human cells
Rossmeislová, Lenka ; Hozák, Pavel (advisor) ; Forstová, Jitka (referee) ; Anděra, Ladislav (referee)
Promyelocytic leukemia protein (PML) gene encodes a nuclear protein localizing into the nucleoplasm and distinct nuclear bodies, referred to as PML nuclear bodies (PML NBs). PML is now considered as a gene with tumor-suppressive properties since it is implicated in many nuclear functions affecting cellular proliferation, apoptosis and senescence. The presented work is a part of a larger project that aims to clarify the regulation of promyelocytic leukemia protein expression and investigates the role of PML protein in cellular senescence. The specific goals of my PhD project were to evaluate new in vitro models for the study of PML, to elucidate the effects of histone deacetylase inhibitors on PML gene expression, and to investigate the association of PML with the nucleolus.
Properties and function of middle T antigen of the murine polyomavirus
Fabiánová, Anna ; Forstová, Jitka (advisor) ; Čáp, Michal (referee)
Polyomaviruses are small DNA viruses, which are able to induce a broad variety of tumors. The main oncoprotein of the mouse polyomavirus (MPyV) is middle T antigen (MT antigen) which is able to transform cells. MT antigen has not an enzymatic activity of its own. It is able to activate signal transduction of host cells through its interactions with certain cellular proteins. These proteins include protein phosphatase 2A (PP2A), Src kinase, phosphatidylinositol 3 kinase (PI3K), Shc protein, 14-3-3 protein and phospholipase Cγ1 (PLCγ1). This work is focused on interaction between MT antigen and cellular proteins and on the impact of this interaction on cell transformation. Since MT antigen is a potent oncogene, the work also deals with the character of transformed cells and tumor development in mouse mammary epithelium. Keywords: polyomaviruses, MT antigen, PP2A, PI3K, PLCγ1, Shc protein, 14-3-3 protein

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2 Forstová, Jana
2 Forštová, Jana
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