|
|
Viruses and cytosketelon of the cell nucleus
Cibulka, Jakub ; Forstová, Jitka (advisor) ; Šťovíček, Vratislav (referee)
The nuclear cytoskeleton (the nucleoskeleton) provides a structural integrity to the nucleus and is involved in number of key processes including transcription, chromatin remodelling and mRNA transport. The nucleoskeleton consists of nuclear lamins, nuclear actin and other proteins. Some viruses, which replicate themselves in the nucleus, use nuclear cytoskeleton in their life-cycle. On the other hand the nucleosketon may also represent a barrier for viral infection. Herpesviruses need nuclear actin for capsid assembly and transport, but they have to desintegrate the nuclear lamina in order to escape the nucleus. Nuclear actin also participates in the morphogenesis and probably nuclear export of baculovirus capsids. Some retroviruses transport their unspliced RNAs from the nucleus using nuclear actin and there is also some evidence of retrovirus-induced nuclear lamina disruption. In this work, I focus on the interactions of above-mentioned viruses with the nuclear cytoskeleton (namely nuclear actin and lamins).
|
|
|
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.
|
|
|
Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
|
|
|
The role of PML nuclear bodies in herpesvirus infection
Bártová, Jana ; Šroller, Vojtěch (advisor) ; Saláková, Martina (referee)
PML nuclear bodies are protein structures in the cell nucleus that regulate many important cellular processes and are also implicated in antiviral defense. The permanent components of these nuclear bodies include PML, Sp100 and Daxx proteins, many other proteins are transiently associated with PML bodies. PML body components can be SUMOylated, this posttranslational modification is important for the formation of PML bodies and regulation of their function. Components of PML bodies such as PML, Sp100 and Daxx can act as restriction factors limiting the replication of many DNA and RNA viruses. Defense mechanisms mediated by PML bodies are suppressed by viral proteins that inactivate individual components or disrupt the structure of PML bodies. This thesis focuses on the role of PML bodies as restriction factors during infection by DNA viruses of the Herpesviridae family and describes the interactions of PML bodies and viral proteins, using herpes simplex virus 1, human cytomegalovirus and Epstein-Barr virus as examples. Keywords: PML nuclear bodies, restriction factor, antiviral defense, innate immunity, herpesviruses
|
|
|
Significantion of sumoylation for infection by selected viruses replicated in the cell nucleus
Sejpková, Marie ; Forstová, Jitka (advisor) ; Frydrýšková, Klára (referee)
This work introduces association between viruses and host cell with respect to sumoylation process. The main aim is referring to influence of this modification both on virus replication strategy and cell cycle. Sumoylation is essential process for cell regulation interfering with general regulation pathways including those performed by e.g. p53 or PML bodies and also epigenetic changes of chromatin. For viruses, sumoylation means stabilization of viral proteins and better timing each phase of viral cycle through viral protein. One point of view is competition of cell and virus for SUMO machinery. Viruses take advantage of sumoylation for inhibition antiviral defense of cells, regulation cell cycle mainly in apoptosis induction and in general for more successful infection. There are cumulating evidence of new proteins and phenomena connected with sumoylation mechanisms as well as viruses exploiting sumoylation for their benefit. Utilization and abuse of sumoylation by viruses point to future possibilities of cell manipulation and virus ability to intervene to this still relatively poorly understood type of cell regulation.
|
|
|
Viruses and cytosketelon of the cell nucleus
Cibulka, Jakub ; Forstová, Jitka (advisor) ; Šťovíček, Vratislav (referee)
The nuclear cytoskeleton (the nucleoskeleton) provides a structural integrity to the nucleus and is involved in number of key processes including transcription, chromatin remodelling and mRNA transport. The nucleoskeleton consists of nuclear lamins, nuclear actin and other proteins. Some viruses, which replicate themselves in the nucleus, use nuclear cytoskeleton in their life-cycle. On the other hand the nucleosketon may also represent a barrier for viral infection. Herpesviruses need nuclear actin for capsid assembly and transport, but they have to desintegrate the nuclear lamina in order to escape the nucleus. Nuclear actin also participates in the morphogenesis and probably nuclear export of baculovirus capsids. Some retroviruses transport their unspliced RNAs from the nucleus using nuclear actin and there is also some evidence of retrovirus-induced nuclear lamina disruption. In this work, I focus on the interactions of above-mentioned viruses with the nuclear cytoskeleton (namely nuclear actin and lamins).
|
|
|
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.
|
guest ::
