据3月27日的《科学》杂志报道说，研究人员已经研发出了一种创制诱导人类多能干细胞（或称iPS细胞）的方法，在这些细胞中不含外来且可能有害的DNA。 这些发现对在基础生物学研究中所使用的细胞来说是重要的，而且也是人们向生产iPS细胞这一目标迈出的关键性的一步。
这些iPS细胞可用于医疗但却没有添加到细胞中用来重新设定细胞程序的那些物质所带来的危险。这些添加的物质可能会干扰细胞的正常发育。 在研究人员首次对胎儿和成人细胞进行重新编程并使其成为iPS细胞的时候，他们是用基因工程病毒将数个关键性的基因插入到细胞核内，并通过它们来开启重新编程的过程。年轻华裔科学家俞君英为此项研究的并列通讯作者。
俞君英及其同僚现在介绍了另外一种方法。 他们将基因添加到被称作质粒的DNA环中，而这些质粒通常存在于细胞的染色体之外。 接着，研究人员用一种叫做核转染的方法将这些质粒介入到人包皮细胞中。 在质粒中的基因所表达的蛋白质会将细胞重新编程并使其成为iPS细胞。 这些iPS细胞在接着的几轮细胞分裂中会开始失去这些质粒，这样研究人员就可以分离出不含质粒的细胞。 在文章中，作者们提到，其它的研究团队最近也报告了具有同样目标的实验方法，但是这些作者说，他们的方法才是目前唯一的显示能够产生完全不含载体和转基因序列的人类iPS细胞的方法。（生物谷Bioon.com）
更多阅读：俞君英简介
生物谷推荐原始出处：
Science March 26, 2009 DOI: 10.1126/science.1172482
Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences
Junying Yu 1*, Kejin Hu 2, Kim Smuga-Otto 1, Shulan Tian 3, Ron Stewart 3, Igor I. Slukvin 4, James A. Thomson 5*
1 Morgridge Institute for Research, Madison, WI 53707–7365, USA.; Genome Center of Wisconsin, Madison, WI 53706–1580, USA.; Wisconsin National Primate Research Center, University of Wisconsin–Madison, Madison, WI 53715–1299, USA.
2 Wisconsin National Primate Research Center, University of Wisconsin–Madison, Madison, WI 53715–1299, USA.
3 Morgridge Institute for Research, Madison, WI 53707–7365, USA.; Genome Center of Wisconsin, Madison, WI 53706–1580, USA.
4 Wisconsin National Primate Research Center, University of Wisconsin–Madison, Madison, WI 53715–1299, USA.; Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, WI 53706, USA.
5 Morgridge Institute for Research, Madison, WI 53707–7365, USA.; Genome Center of Wisconsin, Madison, WI 53706–1580, USA.; Wisconsin National Primate Research Center, University of Wisconsin–Madison, Madison, WI 53715–1299, USA.; Department of Anatomy, University of Wisconsin–Madison, Madison, WI 53706–1509, USA.
* To whom correspondence should be addressed.
Reprogramming differentiated human cells to induced pluripotent stem (iPS) cells has applications in basic biology, drug development, and transplantation. Human iPS cell derivation previously required vectors that integrate into the genome, which can create mutations and limit the utility of the cells in both research and clinical applications. Here, we describe the derivation of human iPS cells using non-integrating episomal vectors. After removal of the episome, iPS cells completely free of vector and transgene sequences are derived that are similar to human embryonic stem (ES) cells in proliferative and developmental potential. These results demonstrate that reprogramming human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one obstacle to the clinical application of human iPS cells.
