Figure 2.

Alternative cleavage/polyadenylation and AS control neuronal wiring. (A) Regulation of alternative cleavage/polyadenylation and exon skipping control axon branching and axon arborization. (Right) The RBP Elav mediates the skiping of exon 19 and the selection of the long 3′UTR isoform for Dscam1. (Center) The Dscam1 -19 L 3′UTR is required for bifurcation of Drosophila mushroom body (MB) axons, and correct formation of axon arborizations in sLNv neurons. (Left) Loss of Elav or loss of the long 3′UTR of Dscam1 leads to bifurcation and growth defects in mushroom body axons, and loss of axonal arborizations in sLNv neurons. (B) Regulation of AS of shtn1 coordinates axonogenesis and axon elongation. AS of shtn1 leads to two different isoforms via the inclusion/exclusion of two exons. The RBP Ptbp2 mediates the inclusion of two exons to produce the shtn1b/shtn1L isoform. The SHTN1L isoform binds actin to allow the formation of actin filaments, which leads to axonogenesis and axon elongation. In absence of Ptbp2 or shtn1L, axonogenesis is impaired.