%0 Journal Article
%T Structure-Function Model for Kissing Loop Interactions That Initiate Dimerization of Ty1 RNA
%A Alain Laederach
%A David H. Mathews
%A Eric R. Gamache
%A Jung H. Doh
%A Justin Ritz
%A M. Joan Curcio
%A Stanislav Bellaousov
%J Archive of "Viruses".
%D 2017
%R 10.3390/v9050093
%X The genomic RNA of the retrotransposon Ty1 is packaged as a dimer into virus-like particles. The 5กไ terminus of Ty1 RNA harbors cis-acting sequences required for translation initiation, packaging and initiation of reverse transcription (TIPIRT). To identify RNA motifs involved in dimerization and packaging, a structural model of the TIPIRT domain in vitro was developed from single-nucleotide resolution RNA structural data. In general agreement with previous models, the first 326 nucleotides of Ty1 RNA form a pseudoknot with a 7-bp stem (S1), a 1-nucleotide interhelical loop and an 8-bp stem (S2) that delineate two long, structured loops. Nucleotide substitutions that disrupt either pseudoknot stem greatly reduced helper-Ty1-mediated retrotransposition of a mini-Ty1, but only mutations in S2 destabilized mini-Ty1 RNA in cis and helper-Ty1 RNA in trans. Nested in different loops of the pseudoknot are two hairpins with complementary 7-nucleotide motifs at their apices. Nucleotide substitutions in either motif also reduced retrotransposition and destabilized mini- and helper-Ty1 RNA. Compensatory mutations that restore base-pairing in the S2 stem or between the hairpins rescued retrotransposition and RNA stability in cis and trans. These data inform a model whereby a Ty1 RNA kissing complex with two intermolecular kissing-loop interactions initiates dimerization and packaging
%K long terminal repeat-retrotransposon
%K Ty1
%K Saccharomyces cerevisiae
%K RNA secondary structure
%K RNA packaging
%K RNA kissing complex
%K pseudoknot
%K kissing loop
%K SHAPE analysis
%U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5454406/