Identification of the Mechanisms of Protein Transport during Arabidopsis Root Development

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Intellectual merit. In order for multicellular organisms to function properly, individual cells within the organism must be able to share information. One way this can happen in plants is through the directed transport of transcription factors between cells. Estimates are that as many as 17% of all transcription factors move between cells in the model plant, Arabidopsis thaliana. However, the mechanisms regulating transcription factor movement are largely unknown. The goal of this research is to identify and characterize the molecular machinery controlling the cell-to-cell transport of transcription factors using the SHORT-ROOT (SHR) protein as a model for movement in the Arabidopsis root. This research has two specific aims. The first is to characterize and identify proteins required for SHR signaling. Five proteins known to interact with SHR will be the focus of these studies. The second aim is to characterize the dynamics of transcription factor movement in Arabidopsis roots, using proteins tagged with photoconvertible fluorophores. This research has the potential to shed light not only on an essential but poorly understood aspect of plant development (i.e., how proteins are transported between cells), but also on animal development, as there is emerging evidence that some of the trafficking machineries are conserved between these two kingdoms. In addition, since viral proteins are thought to traffic between plant cells by utilizing the endogenous components of the plant transport pathways, this research will likely lead to a better understanding of how viral pathogens are able to propagate an infection throughout the plant. Broader impacts. This research will rely heavily on the assistance of undergraduate researchers. Students will use modern confocal microscopy in the phenotypic analysis of the SHR binding protein lines and in analyzing the effects of chemical inhibitors on SHR movement and localization. In addition, undergraduate and graduate students will benefit from a course in cell-to-cell signaling that incorporates this research into the curriculum. The commitment of the principal investigator to education also includes introducing local high school students to the workings of a high-level research laboratory by inviting students to work in the laboratory for a day. There will also be strong participation in departmental seminars to help postdoctoral and graduate researchers learn how to present their data and to enter into productive mentoring relationships with their future students.