The roles of RNA processing in translating genotype to phenotype.

A goal of human genetics studies is to determine the mechanisms by which genetic variation produces phenotypic differences that affect human health. Efforts in this respect have previously focused on genetic variants that affect mRNA levels by altering epigenetic and transcriptional regulation. Recent studies show that genetic variants that affect RNA processing are at least equally as common as, and are largely independent from, those variants that affect transcription. We highlight the impact of genetic variation on pre-mRNA splicing and polyadenylation, and on the stability, translation and structure of mRNAs as mechanisms that produce phenotypic traits. These results emphasize the importance of including RNA processing signals in analyses to identify functional variants.

BNANC Gapmers Revert Splicing and Reduce RNA Foci with Low Toxicity in Myotonic Dystrophy Cells.

Myotonic dystrophy type 1 (DM1) is a multisystemic disease caused by an expanded CTG repeat in the 3' UTR of the dystrophia myotonica protein kinase (DMPK) gene. Short, DNA-based antisense oligonucleotides termed gapmers are a promising strategy to degrade toxic CUG expanded repeat (CUGexp) RNA. Nucleoside analogs are incorporated to increase gapmer affinity and stability; however, some analogs also exhibit toxicity. In this study, we demonstrate that the 2',4'-BNANC[NMe] (BNANC) modification is a promising nucleoside analog with high potency similar to 2',4'-LNA (LNA). BNANC gapmers targeting a nonrepetitive region of the DMPK 3' UTR show allele-specific knockdown of CUGexp RNA and revert characteristic DM1 molecular defects including mis-splicing and accumulation of RNA foci. Notably, the BNANC gapmers tested in this study did not induce caspase activation, in contrast to a sequence matched LNA gapmer. This study indicates that BNANC gapmers warrant further study as a promising RNA targeting therapeutic.