Cell-to-Cell and Long Distance Signaling
Williams, Emily , Bradley, Robert , Staves, Mark , Blackman, Sheila .
The auxin, 2-4-dichlorophenoxyacetic acid, modulates the inhibitory effects of the integrin-binding peptide, RGD, in suspension cultures of Daucus carota.
We are interested in processes controlling plant development, particularly in cell-cell communication. Integrin is a plasma membrane-spanning protein that links the extracellular matrix to the cytoskeleton of animal cells. We have previously shown that an integrin inhibiting peptide (arginine-glycine-aspartic acid – abbreviated RGD) specifically disrupts somatic embryogenesis in carrot (Daucus carota) which occurs when somatic cells, grown in high concentrations of the auxin, 2,4-dichlorophenoxyacetic acid (2,4-D), are transferred to a medium lacking the hormone. The aim of this work was to identify cellular components that interact with RGD to cause disruption of embryogenesis. Micrography identifies RGD-induced cellular disorganization, and growth arrest within 48 h of application to cultures lacking 2,4-D. Fluorescein diacetate staining for viability shows that cell death occurs within the same time frame only in the absence of 2,4-D. Current models suggest that somatic embryo development upon removal of exogenous 2,4-D is due to the subsequent formation of endogenous auxin gradients. Thus, we propose that RGD interacts with auxin signaling in some way. Since we also found that protoplasts are insensitive to RGD, whether they are made from cultures with or without 2,4-D, we further propose that the RGD effect requires a cell wall component(s). We are currently investigating how the cell wall and auxin affect the cell’s response to RGD.
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1 - Grand Valley State University, Biomedical Science
2 - Grand Valley State University, Cell and Molecular Biology
3 - Grand Valley State University, Biology Department, 1 Campus Drive, Allendale, MI, 49401, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM