Analyse von Mikroproteinen bei der Regulation des Blühzeitpunktes in Arabidopsis

• Antragsteller: Professor Dr. Stephan Wenkel
• Fachliche Zuordnung: Zell- und Entwicklungsbiologie der Pflanzen
• Förderung: Förderung von 2013 bis 2017
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 230144755

MicroProteins (miPs) are small proteins that mainly consist of one domain, which occurs in larger multi-domain proteins. I have discovered the first miProtein family in Arabidopsis, named the LITTLE ZIPPER (ZPR) proteins. ZPR proteins consist of a leucine- zipper motif which is closely related to the leucine-zipper domain found in class III HD-ZIP transcription factors (HD-ZIPIII). ZPR proteins can heterodimerize with HDZIPIII proteins and thus prevent DNA-binding. A hallmark of miProtein is the dominant negative mode of action and they exist in both plants and animals. We have used a bioinformatics approach to screen the Arabidopsis proteome for other examples of miProteins. This proposal describes the exemplary characterization of two new miProteins, miP1a and miP1b, encoding small B-Box proteins. miP1 miProteins share sequence homology with CONSTANS-like B-Box transcription factors. Using a directed yeast-two-hybrid approach we tested all Arabidopsis B-Box transcription factors for their ability to physically interact with miP1a and miP1b. This screen resulted in the identification of CONSTANS, a master regulator of photoperiodic flowering, to interact with miP1 miProteins. Analysis of transgenic plants overexpressing miP1a/b resulted in a severe delay of the floral transition indicative of reduced CO activity. This proposal describes experiments designed to understand the role of miP1a/b in flowering time control. We will examine the protein interactions in more detail using immunoprecipitations, study the spatial expression patterns of miP1a/b and perform a genetic analysis to place miP1a/b in the current network of proteins regulating flowering.

• DFG-Verfahren: Sachbeihilfen
• Internationaler Bezug: China, Dänemark
• Beteiligte Personen: Professor Dr. Chun-Ming Liu; Lene Rasmussen