Poster: Protein targeting & vesicular trafficking
Abs #
662: Toward understanding mechanisms of RNA localization in plants
RNA localization may be an ancient mechanism for producing cytoplasmic asymmetry. Features of mRNA localization that may be conserved include cis-acting elements that target the RNA to a subcellular region, the formation of a protein-RNA complex to effect localization and the role of the cytoskeleton as a “road” for RNA movement. Localized mRNA molecules were first identified <20 years ago in Xenopus embryos. Since then, about 100 localized transcripts have been described in a variety of animal cells. Classic examples of localized transcripts in animal cells include bicoid, oskar or vg1 which are required either for axis specification in the Drosophila oocyte or for pole definition in the Xenopus embryo. More recently, a combination of live cell imaging, biochemistry and genetics has yielded a model for how ASH1 mRNA is localized to the budding tip of a yeast daughter cell. mRNA localization also is essential in plant and algal growth and development. However, only 12 localized transcripts have been identified, 9 of these in a marine alga, Acetabularia acetabulum. To the best of our knowledge, transport of mRNA has never been visualized directly in living plant cells and no localized transcripts have been found in Arabidopsis. We are funded to use microarray analysis of 540 non-redundant sequenced ESTs to rapidly identify hundreds of localized transcripts in this unicell. We are also sequencing 10,000 ESTs at random from our cDNA library. We will test 3 conserved regions for possible function zipcodes using microinjection. Finally, we will take advantage of the giant size and healing abilities of Acetabularia to investigate mechanisms of mRNA localization and the role of the nucleus and cytoskeleton on mRNA transport. Funded by NSF IBN0317151 to DFM.
