Poster abstracts
Poster number 51 submitted by Paolo Sinopoli
fitRNAs: A new class of regulatory small noncoding RNAs
Paolo L. Sinopoli (Department of Molecular Genetics, The Ohio State University), Gina T. Nostramo (Department of Molecular Genetics, The Ohio State University), Alicia Bao (Department of Molecular Genetics, The Ohio State University), Sara Metcalf (Department of Molecular Genetics, The Ohio State University), Anita K. Hopper (Department of Molecular Genetics, Center for RNA Biology, The Ohio State University)
Abstract:
tRNAs are small noncoding RNAs crucial to protein synthesis in all kingdoms of life and among the most abundant molecules in a cell. In all eukaryotic organisms, a subset of tRNA-encoding genes contain introns, which must be removed for tRNAs to gain functionality in protein synthesis. Following removal, free tRNA introns are rapidly degraded. This rapid degradation, coupled with their non-essential nature, has led to the assumption that tRNA introns have no cellular purpose. However, a range of multidisciplinary experiments performed in the Hopper lab indicate that free tRNA introns act as complementarity-dependent mRNA regulators. First, computational analysis of the introns in S. cerevisiae reveals extensive and statistically improbable complementarity to specific mRNAs. In particular, families of tRNA introns such as isoleucine (Ile) and tryptophan (Trp) have regions of complementarity in mRNAs with <1/20,000 probabilities of appearing by chance alone. Second, four lines of biological evidence: (i) deletion of the tRNAIle intron, (ii) inducible transgenic overexpression of the tRNAIle intron, (iii) endogenous tRNA intron accumulation via gene mutants, (iv) stress induced tRNA intron accumulation, all demonstrate that free tRNA introns have an inhibitory effect on mRNAs possessing extensive complementarity. Thus, we propose free introns of tRNAs (fitRNAs) as the newest class of regulatory small noncoding RNAs.
Keywords: tRNA, tRNA introns, regulatory RNA