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Studying dimer formation and effectors of Arabidopsis thaliana nascent polypeptide-associated complex
Klodová, Božena ; Fíla, Jan (advisor) ; Robert Boisivon, Helene (referee)
The development of plant flowers represents a complex process controlled by numerous mechanisms. The creation of double homozygous mutant of both β subunits (sometimes also referred to as basic transcription factor 3) of nascent polypeptide associated complex in Arabidopsis thaliana (further referred to as nacβ1 nacβ2) caused quite a strong defective phenotype including abnormal number of flower organs, shorter siliques with a reduced seed set, and inferior pollen germination rate together with a lower ovule targeting efficiency. Previously, NAC complex was described to be formed as a heterodimer composed of an α- and β-subunit, which binds ribosome and acts as a chaperone in Saccharomyces cerevisiae. In plants, NACβ is connected to stress tolerance and to plant development as a transcription regulator. However, little is known of NAC heterodimer function in plants. In this thesis, yeast two hybrid system (Y2H) and bimolecular fluorescence complementation (BiFC) assays were used to verify the NAC heterodimer formation in A. thaliana and to establish any potential interaction preferences between both NACβ paralogues and five NACα paralogues. To deepen the understanding about molecular mechanisms behind the nacβ1 nacβ2 phenotype, flower bud transcriptome of the nacβ1 nacβ2 double homozygous mutants...
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ALBA-family proteins and their role in male gametophyte development
Náprstková, Alena ; Honys, David (advisor) ; Rothová, Olga (referee)
Alba family proteins are highly conserved in all domains of life. They are involved in RNA metabolism in Archae and Eucarya, while they are involved in the chromatin organisation in Crenarchaea. In animals, ALBA proteins were identified to associate with RNase P/MRP subunits. The objective of my thesis was the characterization of ALBA family proteins in a model plant Arabidopsis thaliana. The Arabidopsis genome contains six genes with close homology, three from Rpp20-like subfamily and three of Rpp25-like subfamily. Here I present the localization of GFP-fused proteins in Arabidopsis stable lines harbouring constructs cloned by Gateway® Technology. ALBA proteins were localized in the cytoplasm and undefined particles in root differentiation zone and in mature pollen. The characterization of the respective T-DNA insertion lines did not reveal significant phenotype defects in growth and development of sporophyte and gametophyte in comparison to Columbia-0 plants, probably because of likely functional redundancy od the paralogs. Expression profiles and localization of ALBA proteins suggest their possible role in differentiation and dehydration stress response in Oryza. They were also observed to associate with repressed mRNA transcripts in storage EPP particles. Collectively, I propose the likely role...
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