National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Reporter expression system for study of silencing of provirus integrated inside transcriptionally active gene
Slavková, Martina ; Hejnar, Jiří (advisor) ; Španielová, Hana (referee)
Retroviral vectors are used as mighty tools for an introduction of recombinant genes into the recipient genome in gene therapy trials. In the vector design, great emphasis is put on safety and efficiency. In spite of a great progress in retroviral vector design with the purpose to stabilize its expression, e.g. introduction of protective elements into the viral regulatory sequences, the current approaches are still not sufficiently effective and the majority of proviruses is transcriptionally silenced. The understanding of the silencing mechanism is of special importance to the optimization of the vector design and handling. In this master thesis, I have designed and constructed an expression system for study of the mechanism involved in the silencing of retroviruses integrated inside gene bodies. This artificial system will be utilized for testing of hypothesis that retroviruses integrated into gene bodies are silenced by DNMT-dependent mechanism and this process is triggered by transcriptional read-through of the provirus from nearby host promoter. I have obtained preliminary results suggesting the validity of the suggested hypothesis; however the verification of general validity of this hypothesis for various retroviruses and elements will be a matter of further studies in our laboratory. Powered by...
Functional genome analysis using the retroviral integration sites permissive for provirus expression in human cells
Miklík, Dalibor ; Hejnar, Jiří (advisor) ; Španielová, Hana (referee)
The expression of retroviral genes depends on the establishment of the provirus - the DNA copy of retroviral genome integrated into the host genome. The transcriptional state of provirus is then influenced by the environment at the site of integration. The phenomenon of proviral silencing is an obstacle to the usage of retroviral vectors and a barrier to the eradication of human immunodeficiency virus type 1 (HIV-1) from infected individuals. Taking advantage of single cell clones bearing one provirus, this diploma thesis investigates the distribution of (epi)genomic features at the sites occupied by stably expressed proviruses. In total, long-term expression profiles of 245 and 255 clones carrying avian sarcoma-leucosis virus (ASLV) and HIV-1, respectively, were obtained. The database-based analysis of 42 integration sites of ASLV and three integration sites of HIV-1 proviruses shows that proviral stable expression highly correlates with the transcriptional start sites (TSS) at the sites of integration. Histone marks characteristic for the proximity of active TSSs and regulatory elements at the sites of integration of stably expressed proviruses confirm this finding. The results presented in this thesis could inspire other analyses investigating the relationship between the integration site and the...

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