Weijers Lab
Cell specification and pattern formation in plant embryos
Work in our group is centred on the problem of how cells acquire identity. Our model system is the early embryo of the plant Arabidopsis thaliana. This weed has been widely recognised as a model plant, with all associated benefits. Embryogenesis in Arabidopsis is relatively simple, and few cells are involved in formation of individual body parts. Furthermore, cell divisions are quite predictable, and positions of cell types almost invariant (Figure 1). However, very little is known about the mechanisms that specify the individual cells, or how cells communicate to form an ordered pattern.
Early embryogenesis in Arabidopsis.
The different colors reflect differential expression of known genes, and hence shown specification of cells already at very early stages. (Figure from Llavata Peris, Rademacher and Weijers [2010] Current Topics in Developmental Biology)
Our studies focus on the initiation of the root meristem, the source of the root system of the plant. Early during embryogenesis, stem cells and organizer (hypophysis) are specified. The establishement of these cell types critically depends on the auxin-depent transcription factor MONOPTEROS (MP). MP acts in the future stem cells to promote specification of the adjacent cell as hypophysis (paper). On of our ambitions is to understand the mechanisms of stem cell and hypophysis specification by MP, and the inductive signaling between stem cells and hypophysis. We have recently identified MP target genes, and among these found two bHLH transcription factors - TMO5 and TMO7 - that mediate MP action in root formation (paper). One of these, TMO7, appears to be transported towards the future hypophysis.
MP action: cell fate specification and cell-cell communication during root initiation
(based on Schlereth et al., [2010] Nature; Figure from Moller and Weijers [2010] NPC Highlights)
We employ genetic, transcriptomic, proteomic and microscopy approaches to answer the following questions:
1. How does MP control specification of stem cells and hypophysis, and how do TMO genes contribute to these processes?
2. What is the mechanism and relevance of TMO7 protein movement?
3. How does auxin accumulation in the hypophysis contribute to cell specification?
4. How is auxin accumulation in different cells in the embryo converted to unique developmental responses?
More information about lab members, MSc thesis opportunities and our publications can be found by following the links on the left.Those interested in pursuing PhD thesis or post-doctoral research in the lab, please contact dr. Dolf Weijers (dolf.weijers-at-wur.nl).
We receive funding from the Netherlands Organization for Scientific Research (NWO; ALW Open Competition, Excellent Chemical Sciences [ECHO] and ALW-VIDI grants), from the European Research Council (Starting Grant 2011) and the European Union (FP7-ITN "SIREN"). Post-doctoral fellows in the lab are and were supported by fellowships from FEBS, EU-Marie Curie and Japanese Society for Plant Physiology.The group participates in COST network "HAPRECI", and Dolf Weijers is a member of the "Young Academy" (DJA), within the Royal Dutch Academy of Sciences (KNAW)