Where We Are Going sections. Our research is focused on defining the molecular mechanisms that control cell fate specification in the Arabidopsis root epidermis. To put it another way, we have been trying to determine what genes and molecules cause epidermal cells in the H position to always become hair cells and epidermal cells in the N position to become non-hair cells. Putting together the results from our work so far, we have come up with a simple model to explain how the process might work. Model for the molecular control of root epidermal cell fate in Arabidopsis.
Arrows indicate positive control and blunted lines indicate negative action.
Click on any word to go to a detailed description of that component. To summarize the model, our research suggests that the fate of an epidermal cell is determined by whether or not it expresses a genetic pathway that inhibits hair cell differentiation. Each of these is proposed to interact with the same bHLH transcription factor and the TTG protein, with the WER protein able to generate an active transcription complex and the CPC protein generating an inactive complex. At present, we do not know the pattern of TTG gene expression in the root. In collaboration with Alan Lloyd's group, we found that the ttg mutant can be functionally complemented by expressing the cDNA of the maize R bHLH gene under the control of the strong cauliflower mosaic virus 35S promoter in Arabidopsis.