Nat. Biotechnol. 28, 617–623 (2010); published online 16 May 2010; corrected after print 7 December 2010

In the version of this article initially published, the address of one of the authors, Young-Joo Jang, was incorrect. The correct address is Laboratory of Cell Cycle & Signal Transduction, WCU Department of NanoBioMedical Science, Institute of Tissue Regeneration Engineering, Dankook University, Cheonan, Korea. The error has been corrected in the HTML and PDF versions of the article.