XVI International Botanical Congess

DST elements are mRNA instability sequences that are highly conserved in the 3' untranslated regions of unstable Small-Auxin-Up-RNAs. We devised a strategy to isolate mutants of Arabidopsis defective in DST-mediated mRNA decay. Two mutants, dst1 and dst2, were isolated that elevated the level of DST-containing reporter transcripts. These and other characteristics of dst1 and dst2 indicate that they harbor mutations in trans-acting factors involved in DST-mediated mRNA decay. These mutants should serve as powerful tools for exploring the molecular mechanisms governing recognition of specific mRNAs for degradation in plants. Because sequence-specific mRNA decay mechanisms likely interface with general mRNA decay pathways, we are also investigating potential RNase components of the general mRNA decay machinery.