National Repository of Grey Literature 3 records found  Search took 0.01 seconds. 
Molecular basis for regulation of cell wall pH in Arabidopsis thaliana
Bogdan, Michal ; Fendrych, Matyáš (advisor) ; Retzer, Katarzyna (referee)
The cell wall is one of the defining parts of the plant cell. Cell walls resist turgor pressure, give plants their rigidity and still allow the cell to grow despite their stiffness. The plant cell wall is a composite material that consists of different elements; thus, the knowledge of the plant cell wall composition helps us understand the impact of the mentioned pH changes. Alterations of plant cell wall properties result in a change of plant cell growth rate. A prime example of this is the modification of wall properties by pH change, termed the acid growth. Although acid growth has been studied for a long time, we still do not fully understand the underlying mechanisms, as we have not yet identified all the agents involved in acid growth and our ability to determine apoplastic pH is limited. Local cell wall pH fluctuations arise also due to plant organs having different roles and being affected by a diverse range of stimuli. Despite the fact that new pH measurement techniques, such as genetically encoded fluorescent probes, were developed in the last two decades, there is still a need to provide a higher spatiotemporal resolution of pH analysis. Key words: Arabidopsis, apoplastic pH, cell growth, acid growth theory, cell wall, auxin, apoplastic pH measurement
Eukaryotic translation initiation factor 3 and its role in plant translation regulation
Raabe, Karel ; Michailidis, Christos (advisor) ; Retzer, Katarzyna (referee)
After transcription, mRNA translation is another highly regulated process in gene expression. In plants, translation regulation plays an important role during progamic phase, fertilization and seed development, where synthesized transcripts are stored and selectively translated later in development. Translation regulation is also broadly used in stress responses as a fast and flexible tool to change gene expression; therefore, it plays an essential role in the survival strategy of sessile organisms like plants. Both regulation of the global translational rate as well as selective regulation of specific transcripts modulate the final gene expression response. Most of the regulatory mechanisms are concentrated in the stage of initiation, which is facilitated by several translation initiation factors. Eukaryotic translation initiation factor 3 (eIF3) is the largest and most complex of these factors, consisting of 12 conserved subunits. Its key function in the initiation is to scaffold the formation of the translation initiation complex and in the scanning mechanism accuracy. In past decades, additional eIF3 functions were discovered acting upon the whole translation cycle, including its importance in global and specific translation regulation. The aim of this work is to review eIF3 functions and to...
Characterization of eukaryotic translation initiation factor 3 subunits (eIF3) in A. thaliana male gametophyte
Linhart, Filip ; Hafidh, Said (advisor) ; Retzer, Katarzyna (referee)
From RNA-to-protein, translation initiation and protein synthesis is mediated by trans-acting factors that recognize mRNA features common to almost all eukaryotes. Eukaryotic translation initiation factor 3 complex (eIF3) is a highly conserved protein complex that recognizes 5'-CAP elements of the mRNA to initiate translation. eIF3 consists of nine subunits, three of them having two isoforms: eIF3A, eIF2B1, eIF3B2, eIF3C1, eIF3C2, eIF3D, eIF3E, eIF3F, eIF3G1, eIF3G2, eIF3H and eIF3K. This work deals with functional characterization, expression and subcellular localization of eIF3B1, eIF3B2 and eIF3E in Arabidopsis thaliana male gametophyte and interaction of eIF3E with the Constitutive photomorphogenesis 9 (COP9) complex as a regulatory complex of eIF3E post-translational control. Here we show that depletion of eif3b1 or eif3b2 is not gametophytic lethal and that the two protein might function redundantly, whereas, knockout of eIF3E causes male gametophyte lethality. Interestingly, eif3b1 show post-fertilization defects during embryogenesis, suggesting that its redundancy with eIF3B2 is restricted to the gametophyte. Gene expression studies revealed high expression of eIF3 subunits in actively dividing zones of leaf primordia, root meristem and root elongation zones as well as in the vegetative...

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