© 2014 Chen et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society. This article is distributed exclusively by the RNA Society for the first 12 months after the full-issue publication date (see <a href="http://rnajournal.cshlp.org/site/misc/terms.xhtml">http://rnajournal.cshlp.org/site/misc/terms.xhtml</a>). After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 3.0 Unported), as described at <a href="http://creativecommons.org/licenses/by-nc/3.0/">http://creativecommons.org/licenses/by-nc/3.0/</a>.
Except where otherwise noted, this item's license is described as © 2014 Chen et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society. This article is distributed exclusively by the RNA Society for the first 12 months after the full-issue publication date (see <a href="http://rnajournal.cshlp.org/site/misc/terms.xhtml">http://rnajournal.cshlp.org/site/misc/terms.xhtml</a>). After 12 months, it is available under a Creative Commons License (Attribution-NonCommercial 3.0 Unported), as described at <a href="http://creativecommons.org/licenses/by-nc/3.0/">http://creativecommons.org/licenses/by-nc/3.0/</a>.