National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
4E translation initiation factors and their influence on regulation of gene expression
Lettrich, Patrik ; Mašek, Tomáš (advisor) ; Převorovský, Martin (referee)
The translation represents one of the most crucial processes in the cell. That is why it is often targeted by various regulations. Its initiation phase has a particularly important role in regulatory processes. Initiation of translation usually starts by recognition and binding of canonical eukaryotic initiation factor 4E1 (eIF4E1) to the methylguanosine cap present on the 5' end of the majority of eukaryotic mRNA. The family of 4E translation initiation factors contains two more members - eIF4E2 and eIF4E3. Those two proteins can bind cap structure as well which predetermines it to function in the regulation of translation. Protein eIF4E2 is well known for being a translational repressor in development processes and it takes part in specific miRNA-dependent silencing. It was proven to be able to initiate translation in hypoxia which is consistent with its proposed role in hypoxic tumor cells. The biological roles of the protein eIF4E3 are much less understood. This thesis propounds the picture of the overall functions of all discussed translation initiation factors using cell lines with their overexpression or deletion. Experimental data confirmed the role of the eIF4E2 in the regulation of developmental processes. Cell lines with deleted eIF4E2 and eIF4E3 were characterized based on the influence...
Interactome of the translation initiation factor eIF4E2
Lettrich, Patrik ; Pospíšek, Martin (advisor) ; Zeman, Jakub (referee)
Regulation of gene expression at the level of translation is one of the most prominent processes when it comes to maintaining cellular vital functions in physiolgical norm. Initiation phase plays an especially important role in translational regulation. Majority of eukaryotic mRNAs possess methylguanosine cap on its 5' end. Binding of initiation factor eIF4E1 to cap is substantial part of canonical mechanism of translational initiation. eIF4E1 is component of bigger complex termed eIF4F, whose association with cap mRNA is essential for initiation of translation. Due to cap-binding ability of noncanonical initiation factors and their interaction partners, that are distinct from those of eIF4E1, there can occur specific regulation of translational initiation. One of these noncanonical factors is eIF4E2. In regulatory processes it mostly acts as a translational repressor. Binding of eIF4E2 to cap impedes association of eIF4F complex with mRNA, and therefore inhibits translation. However, eIF4E2 is also able to promote cap-dependent initiation of translation using an alternative mechanism in hypoxic conditions. This thesis represents the first complex analysis of protein-protein interactions and physiological functions of factor eIF4E2 and its homologs in several model organisms. Key words:...

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