Nontemplated Nucleotide Additions Distinguish the Small RNA Composition in Cells from Exosomes Koppers-Lalic, Danijela Hackenberg , Michael Bijnsdorp, Irene V. Eijndhoven, Monique A. J. van Sadek, Payman Sie, Daud Zini, Nicoletta Middeldorp, Jaap M. Ylstra, Bauke Menezes, Renee X. de Würdinger, Thomas Meijer, Gerrit A. Pegtel, D. Michiel Biomolecules Noncoding RNAs (ncRNAS) Exosomes B cells (Human) Posttranscriptional modifications Functional biomolecules, including small noncoding RNAs (ncRNAs), are released and transmitted between mammalian cells via extracellular vesicles (EVs), including endosome-derived exosomes. The small RNA composition in cells differs from exosomes, but underlying mechanisms have not been established. We generated small RNA profiles by RNA sequencing (RNA-seq) from a panel of human B cells and their secreted exosomes. A comprehensive bioinformatics and statistical analysis revealed nonrandomly distributed subsets of microRNA (miRNA) species between B cells and exosomes. Unexpectedly, 3′ end adenylated miRNAs are relatively enriched in cells, whereas 3′ end uridylated isoforms appear overrepresented in exosomes, as validated in naturally occurring EVs isolated from human urine samples. Collectively, our findings suggest that posttranscriptional modifications, notably 3′ end adenylation and uridylation, exert opposing effects that may contribute, at least in part, to direct ncRNA sorting into EVs. 2014-11-27T07:43:18Z 2014-11-27T07:43:18Z 2014 journal article Koppers-Lalic, D.; et al. Nontemplated Nucleotide Additions Distinguish the Small RNA Composition in Cells from Exosomes. Cell Reports, 8: 1649-1658 (2014). [doi: 10.1016/j.celrep.2014.08.027] 2211-1247 http://hdl.handle.net/10481/33899 10.1016/j.celrep.2014.08.027 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Cell Press