We address the challenge of detecting the contribution of noncoding mutations to disease with a deep-learning-based framework that predicts specific regulatory effects and the deleterious impact of genetic variants. Applying this framework to 1,790 Autism Spectrum Disorder (ASD) simplex families reveals disease causality of noncoding mutations: ASD probands harbor both transcriptional and post-transcriptional regulation-disrupting de novo mutations of significantly higher functional impact than unaffected siblings. Further analysis suggests involvement of noncoding mutations in synaptic transmission and neuronal development, and taken together with prior studies reveal a convergent genetic landscape of coding and noncoding mutations in ASD. We demonstrate that sequences carrying prioritized proband mutations possess allele-specific regulatory activity, and highlight a link between noncoding mutations and IQ heterogeneity in ASD probands. Our predictive genomics framework illuminates the role of noncoding mutations in ASD, prioritizes high impact mutations for further study, and is broadly applicable to complex human diseases.

Highlights d Large panel of isogenic APP and PSEN1 mutant iPSCs generated by CRISPR/Cas9 knockin d Transcriptomic and translatomic analyses identify changes in AD and endosomal genes d Rab5 early endosome enlargement is common in APP and PSEN1 mutant neurons d b-CTF mediates endosomal dysfunction, not Ab

mRNA turnover is a critical step in the control of gene expression. In mammalian cells, a subset of mRNAs regulated at the level of mRNA turnover contain destabilizing AU-rich elements (AREs) in their 3 untranslated regions. These transcripts are bound by a suite of ARE-binding proteins (AUBPs) that receive information from cell signaling events to modulate rates of ARE mRNA decay. Here we show that a key destabilizing AUBP, tristetraprolin (TTP), is repressed by the p38 mitogen-activated protein kinase (MAPK)-activated kinase MK2 due to the inability of phospho-TTP to recruit deadenylases to target mRNAs. TTP is tightly associated with cytoplasmic deadenylases and promotes rapid deadenylation of target mRNAs both in vitro and in cells. TTP can direct the deadenylation of substrate mRNAs when tethered to a heterologous mRNA, yet its ability to do so is inhibited upon phosphorylation by MK2. Phospho-TTP is not impaired in mRNA binding but does fail to recruit the major cytoplasmic deadenylases. These observations suggest that phosphorylation of TTP by MK2 primarily affects mRNA decay downstream of RNA binding by preventing recruitment of the deadenylation machinery. Thus, TTP may remain poised to rapidly reactivate deadenylation of bound transcripts to downregulate gene expression once the p38 MAPK pathway is deactivated.