RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States; Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States
Alicia A Bicknell
RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, United States; John A Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States
Melissa J Moore
RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States
The polarized structure of axons and dendrites in neuronal cells depends in part on RNA localization. Previous studies have looked at which polyadenylated RNAs are enriched in neuronal projections or at synapses, but less is known about the distribution of non-adenylated RNAs. By physically dissecting projections from cell bodies of primary rat hippocampal neurons and sequencing total RNA, we found an unexpected set of free circular introns with a non-canonical branchpoint enriched in neuronal projections. These introns appear to be tailless lariats that escape debranching. They lack ribosome occupancy, sequence conservation, and known localization signals, and their function, if any, is not known. Nonetheless, their enrichment in projections has important implications for our understanding of the mechanisms by which RNAs reach distal compartments of asymmetric cells.
