Figure 2.

Alternate UTR usage can modify the localization and developmental effects of a transcript. (A) Bdnf transcription can begin from one of nine alternate promoters. The promoter choice affects the 5′UTR sequence, but not the coding sequence or 3′UTR. Bdnf transcribed from the fourth promoter (cyan dots) localizes to proximal dendrites, while transcription from the sixth promoter localizes it to distal dendrites (yellow dots). Bdnf IV localization to proximal dendrites promotes dendritic formation. (B) Cdc42 has alternate last exons that determine its 3′UTR. The upstream last exon localizes Cdc42 mostly to the cell body of the neuron (yellow dots), and contains a palmitoylation site. This 3′UTR variant promotes spine formation. The downstream last exon containing a prenylation site enriches the transcript to neurites and axons (pink dots) and promotes axogenesis.