Protein-RNA Networks Regulated by Normal and ALS-Associated Mutant HNRNPA2B1 in the Nervous System

HnRNPA2B1 encodes an RNA binding protein associated with neurodegeneration. However, its function in the nervous system is unclear. Transcriptome-wide crosslinking and immunoprecipitation in mouse spinal cord discover UAGG motifs enriched within ∼2,500 hnRNP A2/B1 binding sites and an unexpected role for hnRNP A2/B1 in alternative polyadenylation. HnRNP A2/B1 loss results in alternative splicing (AS), including skipping of an exon in amyotrophic lateral sclerosis (ALS)-associated D-amino acid oxidase (DAO) that reduces D-serine metabolism. ALS-associated hnRNP A2/B1 D290V mutant patient fibroblasts and motor neurons differentiated from induced pluripotent stem cells (iPSC-MNs) demonstrate abnormal splicing changes, likely due to increased nuclear-insoluble hnRNP A2/B1. Mutant iPSC-MNs display decreased survival in long-term culture and exhibit hnRNP A2/B1 localization to cytoplasmic granules as well as exacerbated changes in gene expression and splicing upon cellular stress. Our findings provide a cellular resource and reveal RNA networks relevant to neurodegeneration, regulated by normal and mutant hnRNP A2/B1. [Display omitted] •HNRNPA2B1 interacts with UAGG in 3′ UTRs to affect alternative polyadenylation•HNRNPA2B1 affects alternative splicing of ALS-associated D-amino acid oxidase•HNRNPA2B1 D290V causes widespread splicing changes in fibroblasts and motor neurons•ALS mutant motor neurons display abnormal molecular and cellular stress responses HNRNPA2B1 is associated with neurodegeneration, but its role in the nervous system and effects of mutations are unclear. Martinez et al. discover HNRNPA2B1-dependent alternative splicing and polyadenylation in spinal cord. Stressed mutant motor neurons exhibit abnormal molecular responses and aggregation.