Aktivierung und Inaktivierung von Arabidopsis thaliana Cryptochromen durch BIC1
Loading...
Files
Date
relationships.isAuthorOf
Publisher
Philipps-Universität Marburg
item.page.supervisor-of-thesis
Abstract
The focus of this study was to improve the understanding of the activation and deactivation of A. thaliana cryptochromes, particularly with regard to the inhibition of cry1 and cry2 by the antagonistic protein Blue Light Inhibitor of Cryptochromes 1 (BIC1). In the first studies of BICs after their discovery in 2016, BIC1 and BIC2 from A. thaliana showed distinct and specific inhibitory effects on the cryptochromes (Wang et al., 2016). Using various protein-biological and plant-physiological methods in this work, some of these inhibitory effects were confirmed and further data on the role of BICs provided.
Overexpression lines of BIC1 in A. thaliana Col-0 background showed longer hypocotyls under blue light, delayed flowering under long-day conditions, and a shade avoidance response even under long day conditions with strong white light during the day. These observations demonstrated a partial inhibition of cryptochromes through BIC1 overexpression and therefore a dose-response of cryptochrome activity.
In vitro studies focused on heme-binding by BIC1 (initially demonstrated in the dissertation of N. Niemann, Philipps-University of Marburg, 2021) were continued. A general affinity of heme to BIC1 was confirmed in vitro and in planta. Through the replacement of the three cysteine residues in BIC1 by alanines (BIC13CA mutant), it was shown that this mutant protein when heterologously expressed in E. coli is incapable of binding heme. Likewise, this mutant no longer exhibited the formation of intermolecular disulfide bridges which were observed in BIC1WT when recombinantly expressed in E. coli. However, BIC13CA still showed biological activity in planta, indicating that the ability to form intermolecular disulfide bridges are not essential for the BIC1 inhibition of cryptochromes.
The formation of photobodies by cry1 under strong blue light described by Liu et al. (2022) were confirmed in this study. In contrast to previous results, photobodies were not only identified in the nucleus but also in the cytoplasm of N. benthamiana leaf cells. The formation of cry1 photobodies was inhibited by co-expression of BIC1, confirming the results of Liu et al. (2022). Further work is needed to identify the function and biological relevance of these cry1 photobodies.
Review
Metadata
Contributors
Supervisor:
Dates
Created: 2023Issued: 2024-06-18Updated: 2024-06-18
Faculty
Fachbereich Biologie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
BIC1PhotobiologyCryptochromesBlaulicht
DFG-subjects
CryptochromPhotobiologiePflanzenphysiologieAckerschmalwand
DDC-Numbers
570
show more
Kock, Dennis: Aktivierung und Inaktivierung von Arabidopsis thaliana Cryptochromen durch BIC1. : Philipps-Universität Marburg 2024-06-18. DOI: https://doi.org/10.17192/z2023.0590.
License
This item has been published with the following license: In Copyright