Poster: Protein targeting & vesicular trafficking
Abs #
658: A chemical genomics screen for compounds that affect gravitropism and vacuolar biogenesis.
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Presenter: |
Rojas-Pierce, Marcela , mrojas@ucr.edu |
Authors | Rojas-Pierce, Marcela (A) Surpin, Marci (A) Carter, Clay J. (A) Vasquez, Jacob (A) Raikhel, Natasha (A) | | Affiliations: |
(A): Department of Botany and Plant Sciences, University of California, Riverside.
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Plant vacuoles are dynamic compartments that may occupy up to 90% of the cell volume. These compartments are involved in multiple functions such as maintenance of cellular turgor, storage of proteins and protein degradation. A link between vacuolar function and gravitropism has recently been established with the characterization of agravitropic mutants, such as sgr2 and zig. These mutants have lesions in components of the endomembrane system and have abnormal vacuolar morphology (Plant Cell. 2002,14: 33-46, Plant Cell. 2002,14: 47-56). Based on these results, it has been proposed that the vacuole is involved in perception of gravitropism in plants.
The limitations of classical genetic approaches to study vacuoles was demonstrated by the isolation of a single vacuoless (vcl) mutant in Arabidopsis from a screen of over 5,000 T-DNA insertion lines (Dev Cell. 2001,1: 303-310). Also, several T-DNA insertions in other components of the endomembrane system result in gametophytic or embryo lethality. To overcome these limitations, a chemical genomics approach has been initiated to facilitate our understanding of vacuolar biogenesis. A screen for compounds that affect shoot gravitropism in Arabidopsis is currently under way using a diverse chemical library of small compounds. The effect of 10,000 chemicals on the gravitropic response has been tested in a semi-high-throughput system. A secondary screen has been initiated using a tonoplast reporter line that carries a GFP fused to the δ-Tonoplast Intrinsic Protein to identify compounds that affect vacuolar morphology by confocal microscopy. The effect of these compounds on gravitropism and endomembrane system morphology is currently being characterized, and screens for resistant and hypersensitive mutants are under way.
