19 Oral - Neurodevelopment I
Thursday April 07, 5:15 PM - 5:30 PM

Authors:
Peter M'Angale; Adrienne Lemieux; Alfred Simkin; Cong Xiao; Vivian Budnik; Travis Thomson

Affiliation: University of Massachusetts Chan Medical School, Worcester, MA

Keywords:
f. neuromuscular junction; q. RNA transport and localization

Despite advances in elucidating the genome, the function, of much of the genetic material, the so called “junk DNA”, remains largely unknown. A large portion of junk DNA is comprised of genomic parasites, known as transposable element (TEs). New evidence suggests that a domesticated TE, activity-regulated cytoskeleton-associated protein 1 (Arc1), serves as a mechanism to transport RNAs across the synapse. Here we show that a TE, Copia is enriched at the Drosophila NMJ and Copia is transported across synapses in extracellular vesicles (EVs). We observe Copia^gag acting antagonistically to dArc1. Strikingly, downregulation of Copia^gag at the Drosophila NMJ results in abnormal NMJ development and increased plasticity. From RNA-sequencing data coupled with digital PCR, we determined that copia is encoded by ~40 different loci each of which is found at different abundances in the Drosophila larval brain or body wall muscles. To our knowledge, this is the first report documenting a physiological role of a TE at synapses, lending further weight to recent arguments and data suggesting that TEs and potentially other types of “junk DNA” are not junk after all.