Project

TCP transcription factors and organ growth

Development in higher plants is characterized by the reiterative formation of organs produced from meristems. These meristems maintain a pool of pluripotent ‘stem cells’ which enable the differentiation into stems and leaves during the vegetative phase of development, and flowers and fruits during the generative phase. In interaction with environmental factors, the initiated organs grow up to particular sizes and shapes under the control of tightly regulated genetic programs that direct cell proliferation and cell expansion.

Rosette leaves from a wild type plant and mutant with enlarged final leaf sizes. Bottom: Expression of a TCP transcription factor in young leaf primordial visualised by fusion of the genomic TCP fragment to the Green Fluorescent Protein (GFP) encoding sequence.
Rosette leaves from a wild type plant and mutant with enlarged final leaf sizes. Bottom: Expression of a TCP transcription factor in young leaf primordial visualised by fusion of the genomic TCP fragment to the Green Fluorescent Protein (GFP) encoding sequence.

Understanding the processes that orchestrate growth is one of the most crucial challenges of today’s plant research community and is essential to produce sufficient biomass for food and non-food applications in the near future. Our goal is to understand how growth is regulated at the molecular level and in relation to this topic we address the following two questions:

How do particular regulatory proteins (TCP transcription factors) coordinate growth in a developing leaf?
How is floral organ identity specification coupled to floral organ growth at the molecular level?
Members of the plant-specific TCP class of transcription factors are known to effect organ growth. We are applying various genome-wide approaches (e.g. Chromatin Immunoprecipitation: ChIP-seq) in order to find the target genes and biological processes that are under direct control of TCP proteins. Furthermore, functional analyses and protein-protein interaction studies are performed for TCP proteins and obtained data are integrated into a regulatory network for leaf growth.

A second class of transcription factors under investigation is the MADS box family.  Members from this family are well known for their pivotal role in the specification of floral organ identity during initial stages of flower development. Remarkably, MADS box transcription factors are not only expressed during the early stages of floral organ formation, but also at later stages. We have found evidence that this late expression is essential for the correct differentiation and growth of the floral organs. Currently, both functional and molecular analyses are performed to elucidate the role of MADS domain proteins in floral organ growth and a couple of co-factors have been identified that might be essential for this function.

Publications

Urbanus, S.L., Martinelli, A.P., Dinh, Q.D., Aizza, L.C., Dornelas, M.C., Angenent, G.C., and Immink, R.G.H. (2010). Intercellular transport of epidermis-expressed MADS domain transcription factors and their effect on plant morphology and floral transition. Plant Journal 63, 60-72.
Immink, R.G.H., Kaufmann, K., and Angenent, G.C. (2010). The ABC of MADS domain protein behaviour and interactions. Semin Cell Dev Biol 21, 87-93.
Dornelas, M.C., Maistro Patreze, C., Angenent, G.C., and Immink, R.G.H. (2010). MADS: The missing link between identity and growth?  Trends in Plant Sciences. Doi:10.1016/j.tplants.2010.11.003.
Urbanus, S.L., De Folter, S., Shchnnikova, A., Kaufmann, K., Immink, R., and Angenent, G.C. (2009). In Planta localization patterns of MADS domain proteins. BMC Plant Biology 9:5. doi:10.1186/1471-2229-9-5.

Websites

EU-FP6, AGRON-OMICS: Arabidopsis GROwth Network integrating OMICS technologies

CBSG (Centre for Biosystems Genomics): In vivo imaging and protein behaviour. 


Arabidopsis leaf cells in wild type and mutants
Arabidopsis leaf cells in wild type and mutants