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The role of IFI16 protein in viral infection
Karchňák, Jan ; Šroller, Vojtěch (advisor) ; Poláková, Ingrid (referee)
6 Abstract Viruses are obligate intracellular parasites causing a large variety of diseases. Most of their hosts, including humans, have developed particular mechanisms, which are meant to tackle such diseases. First line of defense against viruses are pattern recognition receptors. These receptors are responsible for detection of pathogen associated molecular patterns (PAMPs) and of damage associated molecular patterns (DAMPs). Inteferon γ inducible protein 16 (IFI16) is one of these receptors and is responsible for detecting alien and damaged DNA both in the nucleus and cytoplasm. Its structure contains two sequence independent DNA binding HIN domains and one PYD domain, which mediates its protein-protein interactions. In the cell it functions as a regulator of cell cycle, differentiation and plays a role in cell aging. IFI16 also triggers activation of non-specific immune response and it directly acts as a restrictive factor for many viruses. During evolution these viruses have evolved mechanism which they us to evade its imunne activity or even use it to their advantage. Keywords: IFI16, STING, DNA sensing, interferons, restriction factor, pattern recogniton receptors
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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
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The role of the Smc5/6 complex in DNA viral infection
Protivová, Eliška ; Huerfano Meneses, Sandra (advisor) ; Pokorná, Karolína (referee)
The Smc5/6 complex is an eukaryotic protein complex that, together with Smc1/3 cohesin and Smc2/4 condensin, is involved in ensuring genome stability. It contributes to this by participating in the organization and maintenance of chromosomal structures as well as in the response to DNA damage. In addition, the Smc5/6 complex has been shown to play an important role in viral infection. This thesis focuses on the mechanisms of interaction of the Smc5/6 complex with viral DNA genomes, DNA intermediate genomes and viral proteins. In the case of HBV of the Hepadnaviridae family, Smc5/6 acts as a restriction factor. The same is true for HSV-1 of the Herpesviridae family, viruses of the Papillomaviridae family and HIV-1 of the Retroviridae family. An interaction of the Smc5/6 complex with the JC virus of the Polyomaviridae family has also been discovered. Nevertheless, the meaning of this interaction remains elusive. Some of the above-mentioned viruses can prevent this restriction. In detail, HBx protein of HBV mediates proteasomal degradation of the Smc5/6 complex or Vpr protein of HIV-1 induces degradation of the SLF2 protein, which is responsible for the Smc5/6 localization on HIV-1 DNA intermediate genomes. Keywords: Smc5/6 complex, DNA repair, ATPase, sumoylation, DNA viruses, viruses with a DNA...
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