AS

Regulation and functions of mRNA processing in plant development and stress responses

01.06.2018 bis 31.12.2018

Precursor messenger RNAs (pre-mRNAs) undergo extensive co- and posttranscriptional modification, which massively expands transcriptome diversity and plays an important role in gene control. Among those processing mechanisms, alternative pre-mRNA splicing (AS) is particularly widespread in plants and other higher eukaryotes and allows the formation of mRNA variants by removing distinct intronic regions and joining the remaining exons. AS can give rise to transcripts encoding different proteins or generate mRNAs containing certain cis-elements such as premature termination codons, which trigger mRNA degradation via the RNA surveillance pathway nonsense-mediated decay (NMD). Interestingly, coupling of AS and NMD is prevalent and has been demonstrated to affect almost 20% of all multi-exon genes in Arabidopsis thaliana. Despite their widespread occurrence and enormous regulatory potential, control of AS and NMD are only poorly understood and their functions in development and stress responses have been only rudimentarily addressed in plants. The research projects proposed in the context of this Heisenberg stipend are aiming at filling this fundamental knowledge gap. Based on our previous identification of Polypyrimidine tract binding proteins (PTBs) as important regulators of AS in A. thaliana, the interaction networks of splicing factors and cis-regulatory motifs in AS control will be examined, deciphering critical components of the plant splicing code. The molecular determinants of splicing factor specificity will be further addressed by studying common and distinct functions of plant PTB splicing regulators, which are present as single genes in basal plant species, while evolutionary conserved subgroups are found in mono- and dicots.