Prof. Dr. Dietz
PROJECT INFORMATION :
The proposed research aims at understanding the extremely rapid effect of chloroplast metabolic state on cytosolic translation mediated by control of ribonucleoproteins. The project takes advantage of the kinetically precise experimental design of low light-to-high light- (L-H)-transfer and exploits the very fast conditional reorganization of the translatome. The stress associated Zinc-finger protein SAP3 will be used as an example to test the specificity and function of three sequence motifs found to be highly overrepresented in the 5’-UTR among the 272 transcripts preferentially associated with the polysomes 10 min after L-H-transfer. Using RNAseq on polysomal RNAs we will refine the data set of rapid ribosome-recruited mRNAs and the reversibility of this regulatory process. The significance of the three motifs and the 5’-UTR and 3’-UTR in H-L-transfer will be scrutinized by using transfected protoplasts and stably transformed sap2/sap3-double mutants of Arabidopsis thaliana. RBPs will be identified that bind to the motifs and the UTRs and dynamic differences between the polysomal proteomes of low light and L-H-samples will be identified. The molecular and physiological role of identified RBPs will be investigated in vitro und in vivo. In order to complete the understanding of the involved pathways and signals, upstream coupling of the translational L-H-regulation to the MAP kinase pathway will be addressed using defined genetic mutants, e.g. mpk6. Regulation of downstream target genes like the sigma factor 5 and small HSPs will be assessed by physiological analysis of knock out plants. This project is integrated into the framework of SPP1935 according to the specific aims and work plan defined in the call, i.e. clarification of regulation and dynamics of RNPs, establishment and application of technologies for specific RNP isolation and identification, and expansion of the specific regulatory network including upstream and downstream elements in context of the fundamental process of light acclimation in higher plants.
KEY TECHNOLOGIES :
- Protein biochemistry (purified and recombinant proteins)
- Isothermal titration microcalorimetry
- Dynamic cell imaging (one step and two step FRET)
- Transgenic organisms.
König J, Baier M, Horling F, Kahmann U, Harris G, Schürmann P, Dietz KJ (2002) The plant-specific function of 2-Cys peroxiredoxin-mediated detoxification of peroxides in the redox-hierarchy of photosynthetic electron flux. PNAS USA 99, 5738-5743.
Park SW, Li W, Viehhauser A, Kim S, Nilsson AK, Andersson MX, Kittle JD, Ambavaram MMR, Luan S, Esker AR, Tholl D, llerström M, Coaker G, Mitchell TK, Pereira A, Dietz KJ, Lawrence CB (2013) Cyclophilin 20-3 relays a 12-oxo-phytodienoic acid signal during stress responsive regulation of cellular redox homeostasis. PNAS USA 110, 9559-9564.
Alsharafa A, Vogel MO, Oelze ML, Moore M, Stingl N, König K, Friedman H, Mueller MJ, Dietz KJ (2014) Kinetics of retrograde signalling initiation in the high light response of Arabidopsis thaliana. Philosophical Transactions of the Royal Society of London 369, 20130424.
Vogel MO, Moore M, König K, Pecher P, Alsharafa K, Lee J, Dietz KJ (2014) Fast retrograde signalling in response to high light involves metabolite export, mitogen activated protein kinase 6 and AP2/ERF-transcription factors. Plant Cell 26, 1151-1165.
Moore M, Gossmann N, Dietz KJ (2016) Redox regulation of cytosolic translation in plants. Trends Plant Sci 21: 388-397.