PD Dr. Jörg Meurer

Research

Chloroplast RNA Metabolism

Chloroplasts play a central role in integrating temperature-, light- and redox-induced signals at the molecular level, which is essential for acclimation processes. Imbalances in photosynthetic activity caused by changes in temperature and light require adjustments to the relative abundance of photosynthetic complexes and coordinated regulation of post-transcriptional events through precise modulation of plastid gene expression. For instance, endonucleolytic cleavage within intergenic regions and RNA methylation, such as the installation of prevalent m6A marks, often serve as prerequisites for regulating translation and the stability of specific chloroplast mRNAs.

A surprisingly large number of nuclear genes - several times greater than the number of plastid genes - are involved in regulating plastid RNA metabolism. We have identified many newly evolved, nuclear-encoded RNA-binding proteins in Arabidopsis, including PrfB1, PrfB3, APO1, PAC, RHON1, PUMPKIN and HCF145, which are essentially required for the processing, stabilization, splicing, and methylation of specific plastid or mitochondrial RNAs. It appears that divergence in organellar UTRs provides novel platforms at RNA termini for RNA-binding factors to mediate molecular processes in response to environmental cues.

Assembly of Photosynthetic Membrane Complexes

The photosystems are located in the thylakoid membrane and consist of many subunits and an even greater number of cofactors required for light absorption and photosynthetic electron transport. Their subunits are encoded by both nuclear and plastid genes, so the assembly of these complexes, as well as the synthesis and insertion of cofactors, must be tightly regulated. In recent years, we have identified several nuclear-encoded proteins - such as HCF136, PsbN, HCF101, and PHYLLO - that are indispensable for the accurate delivery and assembly of photosystem components.

An intriguing feature of the photosystems is their abundance of low molecular weight (LMW) subunits, many of which have a molecular mass below 5 kD. Through chloroplast transformation in tobacco, we have generated more than a dozen knockout plants targeting LMW proteins, leading to the identification of individual functions in assembly, stability, electron flow, repair from photoinhibition, state transitions and phosphorylation patterns.

Miscellaneous

radiation protection officer, safety officer, fire protection officer, e-learning ambassador, active member of the Graduate School LSM

Curiculum Vitae

Publications

google scholar