Poster abstracts

Poster number 9 submitted by Eduardo Paredes

Solid-phase synthesis of branched RNA

Eduardo Paredes (Department of Chemistry, Carnegie Mellon University), Tao Han (Department of Chemistry, Carnegie Mellon University), Subha R. Das (Department of Chemistry, Carnegie Mellon University)

Abstract:
In splicing, introns are removed and exons are joined together to generate the correct RNA for translation. The byproduct of splicing is the removed lariat intron. In eukaryotes, lariat introns are branched structures with highly conserved nucleotide sequences around an adenosine branch-point residue that has a 2',5'-phosphodiester linked branch. Branched RNA is a mimic of the natural lariat RNA and known synthetic and DNAzyme based methods to generate branched RNA either do not provide access to natural consensus branched RNA sequences or are limited in the ability to site specifically modify the RNA sequences. We report a simple scheme for the solid-phase synthesis of branched RNA that is not limited to specific sequences and is readily amenable to modified residues and linkages. Using this scheme, the natural yeast branched RNA consensus sequence was synthesized and characterized. This branched RNA is efficiently debranched by yeast debranching enzyme Dbr1. Additionally, unnatural branches including 2',3'-phosphodiester linkages as well as DNA-RNA chimeric analogues were synthesized. The ability to generate branched RNA consensus sequences and to site specifically modify the branched RNA are tools that will help in the study of debranching enzyme and splicing.

Keywords: solid-phase synthesis, branched RNA, lariat intron