Isoform-specific translational control is evolutionarily conserved in primates
Alternative splicing (AS) influences the expression of human genes in diverse ways. We previously used subcellular fraction-sequencing (Frac-Seq) to reveal an unexpected connection between alternative splicing and isoform-specific mRNA translation. Here we apply comparative transcriptomics to explore alternative splicing coupled translational control (AS-TC) across 13 million years of primate evolution. We used Frac-seq to identify polyribosome associated mRNA isoforms from human, chimpanzee and orangutan induced pluripotent stem cell lines. We discovered or­thologous AS-TC events with either conserved or species-specific translation patterns. Exons sequences associated with similar sedimentation profiles between species show strong sequence con­servation compared to orthologous exons with divergent sedimentation profiles, suggesting exonic cis-regulatory elements influence to translational control. To test this hypothesis we created luciferase reporters from orthologous exons with divergent sedimentation profiles differing by a single nucleotide. Remarkably, single nucleotide substitutions were sufficient to drive species-specific expression of luciferase reporters. Together these data establish that cis-acting elements regulate AS-TC across primate species. Overall design: Subcellular Fractionation and RNA sequencing