. Author manuscript; available in PMC: 2010 Jun 1.
Published in final edited form as: Cell Res. 2009 Sep 29;19(12):1388–1400. doi: 10.1038/cr.2009.113
Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms