RESEARCH ARTICLE Allele-Selective Transcriptome Recruitment to Polysomes Primed for Translation: Protein- Coding and Noncoding RNAs, and RNA

mRNA translation into proteins is highly regulated, but the role of mRNA isoforms, noncod-ing RNAs (ncRNAs), and genetic variants remains poorly understood. mRNA levels on polysomes have been shown to correlate well with expressed protein levels, pointing to polysomal loading as a critical factor. To study regulation and genetic factors of protein translation we measured levels and allelic ratios of mRNAs and ncRNAs (including micro-RNAs) in lymphoblast cell lines (LCL) and in polysomal fractions. We first used targeted assays to measure polysomal loading of mRNA alleles, confirming reported genetic effects on translation of OPRM1 and NAT1, and detecting no effect of rs1045642 (3435C>T) in ABCB1 (MDR1) on polysomal loading while supporting previous results showing increased mRNA turnover of the 3435T allele. Use of high-throughput sequenc-ing of complete transcript profiles (RNA-Seq) in three LCLs revealed significant differ-ences in polysomal loading of individual RNA classes and isoforms. Correlated polysomal distribution between protein-coding and non-coding RNAs suggests interactions betwee