Monosomes actively translate synaptic mRNAs in neuronal processes

• Published in: Science (American Association for the Advancement of Science) Vol. 367; no. 6477
• Main Authors: Biever, Anne, Glock, Caspar, Tushev, Georgi, Ciirdaeva, Elena, Dalmay, Tamas, Langer, Julian D, Schuman, Erin M
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 31.01.2020
• Subjects: Animals; Axonal plasticity; Axons; Brain slice preparation; Cell size; Compartments; Dendrites; Dendritic spines; Dendritic structure; Electron micrographs; Electrons; Elongation; Footprinting; Gene sequencing; Hippocampus; Hybridization; Information processing; Male; Mass spectrometry; Mass spectroscopy; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Morphology; Neurons; Neuropil; Neuropil - metabolism; Occupancy; Polypeptides; Polyribosomes; Polyribosomes - metabolism; Preferences; Presynapse; Protein Biosynthesis; Protein synthesis; Proteins; Proteome - metabolism; Proteomes; Proteomics; Ribosomes; Ribosomes - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Rodents; Synapses; Synapses - metabolism; Synaptic plasticity; Transcription; Transcripts (Written Records); Translation
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aay4991

To accommodate their complex morphology, neurons localize messenger RNAs (mRNAs) and ribosomes near synapses to produce proteins locally. However, a relative paucity of polysomes (considered the active sites of translation) detected in electron micrographs of neuronal processes has suggested a limited capacity for local protein synthesis. In this study, we used polysome profiling together with ribosome footprinting of microdissected rodent synaptic regions to reveal a surprisingly high number of dendritic and/or axonal transcripts preferentially associated with monosomes (single ribosomes). Furthermore, the neuronal monosomes were in the process of active protein synthesis. Most mRNAs showed a similar translational status in the cell bodies and neurites, but some transcripts exhibited differential ribosome occupancy in the compartments. Monosome-preferring transcripts often encoded high-abundance synaptic proteins. Thus, monosome translation contributes to the local neuronal proteome.