Comprehensive identification of full-length mRNA isoforms reveals massive diversity of neural cell-surface molecules and illuminates their function in development and disease

ABSTRACT: Genes encoding cell-surface proteins are crucial for nervous system development and are implicated in neurological disorders. These genes produce alternative mRNA isoforms which remain poorly characterized, impeding our understanding of how disease-associated mutations cause pathology. Here we introduce a new strategy to reveal complete full-length isoform portfolios encoded by individual genes. Using our strategy to catalog diversity of neural cell surface molecules, we identified thousands of unannotated isoforms expressed in retina and brain. Mass spectrometry revealed that many newly-discovered proteins are expressed on the cell surface in vivo. Remarkably, we discover that the major isoform of the retinal degeneration gene CRB1 was previously overlooked. This isoform is the only one expressed by photoreceptors, the affected cells in CRB1 disease. By generating mouse mutants, we reveal a function for this isoform at the cell-cell junctions of the retinal outer limiting membrane, and we provide a causal link between loss of this Crb1 isoform and photoreceptor death. Therefore, our isoform identification strategy accelerates discovery of new gene functions relevant to disease.

INSTRUMENT(S): Synapt MS

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Brain

SUBMITTER: Christopher Kozlowski  

LAB HEAD: Jeremy N. Kay

PROVIDER: PXD017290 | Pride | 2020-08-11

REPOSITORIES: Pride