Structures of virus-like capsids formed by the Drosophila neuronal Arc proteins

Arc, a neuronal gene that is critical for synaptic plasticity, originated through the domestication of retrotransposon Gag genes and mediates intercellular messenger RNA transfer. We report high-resolution structures of retrovirus-like capsids formed by Drosophila dArc1 and dArc2 that have surface spikes and putative internal RNA-binding domains. These data demonstrate that virus-like capsid-forming properties of Arc are evolutionarily conserved and provide a structural basis for understanding their function in intercellular communication. Arc, a master regulator of synaptic plasticity, can mediate intercellular RNA transfer. Arc evolved from retrotransposon genes. Erlendsson et al. present structures of retroviral-like Arc capsids as a basis to understand their function.