日本研究人员利用质粒代替病毒载体运送基因，成功用实验鼠体细胞培育出诱导多能干细胞（iPS细胞）。科学家说，这项研究成果将有助于这种“万能细胞”技术的普及。
日本京都大学和科学技术振兴机构10日发布联合新闻公报说，以前培育iPS细胞时，需要依靠逆转
录酶病毒或慢病毒将Oct3／4、Sox2、Klf4和c－Myc这4个基因导入体细胞，而使用病毒载体有可能引发肿瘤形成。此外，每次实验前都要制作新的病毒载体，对操作过程和实验室的管理要求很严格，这都阻碍着iPS细胞技术的普及。
京都大学山中伸弥教授的研究小组在实验中使用了两个质粒，一个质粒运载“c－Myc”基因，另一个质粒运载Oct3／4、Klf4和Sox2基因，然后把两个质粒同时导入实验鼠胚胎成纤维细胞，成功培育出了iPS细胞。
进一步的实验证实，用这种方法培养的iPS细胞与以往的iPS细胞一样能分化生成表皮、横纹肌和神经组织等多种细胞，但转化效率比用逆转录酶病毒为载体要低一些。
研究人员说，下一步的目标是提高转化效率，并尝试用新方法把成体鼠和人类的体细胞培育成iPS细胞。
iPS细胞、胚胎干细胞和成体干细胞因为能分化成多种器官和组织细胞，被称为“万能细胞”。不少研究人员认为，iPS细胞不涉及伦理问题，在再生医疗领域具有更广阔的应用前景。（生物谷Bioon.com）
生物谷推荐原始出处：
Science，DOI: 10.1126/science.1164270，Keisuke Okita，Shinya Yamanaka
Generation of Mouse Induced Pluripotent Stem Cells Without Viral Vectors
Keisuke Okita 1, Masato Nakagawa 2, Hong Hyenjong 3, Tomoko Ichisaka 4, Shinya Yamanaka 5
1 Center for iPS Cell Research and Application (CiRA), Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8507, Japan.
2 Center for iPS Cell Research and Application (CiRA), Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8507, Japan.; Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
3 Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
4 Center for iPS Cell Research and Application (CiRA), Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8507, Japan.; CREST and Yamanaka iPS Cell Project, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan.
5 Center for iPS Cell Research and Application (CiRA), Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8507, Japan.; Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.; CREST and Yamanaka iPS Cell Project, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan.; Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158, USA.
Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by introducing Oct3/4, and Sox2 with either Klf4 and c-Myc or Nanog and Lin28 using retroviruses or lentiviruses. Patient-specific iPS cells could be useful in drug discovery and regenerative medicine. However, viral integration into the host genome increases the risk of tumorigenicity. Here we report the generation of mouse iPS cells without viral vectors. Repeated transfection of a single plasmid containing the cDNAs of Oct3/4, Sox2, and Klf4, together with a c-Myc expression plasmid, into mouse embryonic fibroblasts resulted in iPS cells without evidence of plasmid integration, which produced teratomas when transplanted into mice and contributed to adult chimeras. The production of virus-free iPS cells, albeit from embryonic fibroblasts, addresses a critical safety concern for potential use of iPS cells in regenerative medicine.
