Elav-Mediated Exon Skipping and Alternative Polyadenylation of the Dscam1 Gene Are Required for Axon Outgrowth

Cell Rep. 2019 Jun 25;27(13):3808-3817.e7. doi: 10.1016/j.celrep.2019.05.083.

Abstract

Many metazoan genes express alternative long 3' UTR isoforms in the nervous system, but their functions remain largely unclear. In Drosophila melanogaster, the Dscam1 gene generates short and long (Dscam1-L) 3' UTR isoforms because of alternative polyadenylation (APA). Here, we found that the RNA-binding protein Embryonic Lethal Abnormal Visual System (Elav) impacts Dscam1 biogenesis at two levels, including regulation of long 3' UTR biogenesis and skipping of an upstream exon (exon 19). MinION long-read sequencing confirmed the connectivity of this alternative splicing event to the long 3' UTR. Knockdown or CRISPR deletion of Dscam1-L impaired axon outgrowth in Drosophila. The Dscam1 long 3' UTR was found to be required for correct Elav-mediated skipping of exon 19. Elav thus co-regulates APA and alternative splicing to generate specific Dscam1 transcripts that are essential for neural development. This coupling of APA to alternative splicing might represent a new class of regulated RNA processing.

Keywords: 3′ UTR; CRISPR; Dscam1; Elav; MinION; alternative cleavage and polyadenylation; alternative splicing; axon guidance; exon skipping.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alternative Splicing*
  • Animals
  • Axons / metabolism*
  • Cell Adhesion Molecules / biosynthesis*
  • Cell Adhesion Molecules / genetics
  • Drosophila Proteins / biosynthesis*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster
  • ELAV Proteins / genetics
  • ELAV Proteins / metabolism*
  • Exons
  • RNA 3' Polyadenylation Signals*

Substances

  • Cell Adhesion Molecules
  • Drosophila Proteins
  • Dscam1 protein, Drosophila
  • ELAV Proteins
  • ELAV protein, Drosophila