Investigating a novel role of the oncogene homolog DEK4 in Arabidopsis shoot meristem stem cell signaling

Prof. Dr. Thomas Laux (Institute of Biology III, University of Freiburg)

We investigate the signaling mechanisms regulating stem cell maintenance in the Arabidopsis shoot meristem, which provides the cells for the lifelong formation of new shoot organs. A long standing question in plant biology is how the organization of the shoot meristem is stably maintained, despite the fact that all cells continuously divide. We previously showed that a signaling feedback loop between the stem cells and the subtending organizing center, mediated by WUSCHEL (WUS) and CLAVATA3 activities, regulates the balance between stem cell maintenance and differentiation. We also found, that in the shoot meristem microRNA394 acts as a mobile signal that provides stem cell competence to the underlying cell layers by triggering the competence of cells to respond to WUS signal. The localized expression of miRNA394 and its limited spread provides a mechanistical model of how the position of the stem cell population at the outermost tip of the plant body is determined. In this project, we study the mechanisms underlying the role of miRNA394 signaling in shoot meristem patterning.