To survive in challenging and unpredictable environments, plants have evolved complex regulatory networks that enable them to coordinate many essential biological processes within a cell and across different tissues. How plants accomplish this coordination on the molecular level is a key unanswered question in plant biology. Yet, their strategies clearly rely on rapid and precise gene regulation mediated by transcription factors networks. The need to continuously adapt to environmental changes has led to an expansion of transcription factor families in plants, especially the large number of R2R3 domain MYB and basic helix-loop-helix (bHLH) transcription factors are characteristic for plants.
In the model plant Arabidopsis thaliana, six R2R3 MYB and three bHLH transcription factors control the production of glucosinolates as primary chemical defense compounds. Despite their overall similarity, the six MYB transcription factors have distinct functions in the plant that cannot be explained by their expression patterns. They can thus serve as a model to answer some general questions about the regulation of transcription factor activity (see below). Your project will focus on one or several of these questions depending on your interests and background.
- All six MYB transcription factors can interact with all three bHLH transcription factors, but are there differences in the kinetics of protein-protein binding?
- Which parts of the proteins mediate the formation of MYB-bHLH complexes?
- Does the formation of MYB-bHLH complexes change the affinity of the transcription factors for DNA binding?
- How are R2R3 MYB transcription factors regulated on the protein level (protein turnover, post-translational modification, sub-cellular re-localization)?