Minisymposium 19: Mechanisms of Gene Regulation

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Abs # M1902: Arabidopsis exosome substrates include multiple classes of noncoding and messenger RNA: a tiling microarray study

Presenter:	Belostotsky, Dmitry       Contact Presenter
Authors	Belostotsky, Dmitry  (A)   Chekanova, Julia  (A)   Gregory, Brian  (B)   Reverdatto, Sergei  (A)   Chen, Huaming  (B)   Ecker, Joseph  (B)
Affiliations:	(A): State University of New York at Albany, Albany NY 12222 (B): Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla CA 92037

Exosome is an evolutionarily ancient macromolecular machine composed of multiple 3'-5' exoribonucleases that plays a central role in numerous, mechanistically distinct reactions of RNA processing, proofreading and degradation in the nucleus and cytoplasm. We have defined the composition of the Arabidopsis thaliana exosome via TAP tag-assisted proteomic analysis, as well as conducted genetic and phenotypic characterization of several exosome subunit mutants. In addition, we have established a genetic depletion system for the Arabidopsis exosome subunits via an estradiol-inducible RNA interference (iRNAi). This system is being used for comprehensive, transcriptome-wide definition of the plant exosome substrates, using whole-genome tiling microarrays. We present evidence that the plant exosome acts in processing and/or metabolism of multiple classes of noncoding RNA, including ribosomal, snRNA, snoRNA, numerous small RNA without defined function that are present in MPSS libraries, as well as microRNA precursors and select subset of mRNA. Supported by USDA (DB), NSF (DB, JC, JE) and Damon Runyon Cancer Research Foundation Fellowship (BG)