Junior Group RNA-Based Regulation

We are interested in how plants respond to changing environmental cues and how they integrate this into different developmental programs. We concentrate on two regulatory mechanisms: i) microRNA-directed cleavage of specific mRNAs as a post-transcriptional tool to control mRNA abundance and ii) nucleo-cytoplasmic partitioning of transcription factors as a means to post-translationally regulate signalling. The Junior Research Group was established in 2004.

MicroRNAs (miRNAs) are endogenously expressed 21 to 22 nucleotides long non-coding RNA species that, in plants, down-regulate the abundance of specific target mRNAs with high complementarity by site-directed cleavage, resulting in mRNA degradation. This constitutes an important mechanism to regulate endogenous and exogenous signalling, since many mRNA targets encode transcription factors. We are verifying new miRNA targets in Arabidopsis that were predicted in silico (co-operation with the JG Bioinformatics of Regulation, Marc Rehmsmeier). In co-operation with the Chair of Genome Research (Prof. Weisshaar) we are investigating the regulation by miRNAs of the function of specific transcription factors that belong to the MYB, bHLH, bZIP and homeodomain classes. In Arabidopsis, each of them are represented by large protein families, and many members of these have plant-specific functions. We are also interested in the temporal and spatial regulation of the expression of specific miRNA genes themselves.

Nucleo-cytoplasmic partitioning of transcription factors also constitutes an important regulatory tool for signalling. The identification of a nuclear export signal on a protein that acts in the nucleus strongly suggests a switch-off mechanism for signalling. We screened for transcription factors that constitute cargo substrates for the nuclear export receptor Xpo1/Crm1 in Arabidopsis and we are investigating the role of nuclear export for the function of these proteins. We concentrate on Arabidopsis transcription factors belonging to the same protein families mentioned above.

Team 

Alves Jr., Leonardo (PhD student)
Bürstenbinder, Ute (affiliated technician)
Merkle, Thomas (Group leader)
Niemeier, Sandra (Diploma student)
Palmisano, Ralf (affiliated Postdoc)
Schleppenbäumer, Judith (Diploma student)
Schmied, Katja (PhD student)
Schreiber, Lena (student)
Starmann, Julia (PhD student)