關(guān)于非生殖性成年細(xì)胞能夠被重新編程而成為多能細(xì)胞,、從而能夠分化成任何細(xì)胞類型的發(fā)現(xiàn),，讓人們看到了一些激動人心的可能性。重新編程的細(xì)胞（被稱為“誘導(dǎo)多能干細(xì)胞”,，即iPS細(xì)胞）在再生醫(yī)學(xué)中應(yīng)當(dāng)有巨大潛力,，但目前用來生成它們的方法大多數(shù)都涉及到病毒基因的使用，這有可能使所誘導(dǎo)的細(xì)胞發(fā)生異常,。
兩個小組在本期Nature上報告了一項合作研究工作,，這項工作成功地在沒有使用病毒載體的情況下使人體細(xì)胞產(chǎn)生了多能性。研究人員利用來自病毒的2A肽序列生成一種結(jié)合重新編程因子的“多順反子載體”（multicistronic vector）,，該載體被piggyBac轉(zhuǎn)位子載體送入細(xì)胞中,，從而在人及小鼠成纖維細(xì)胞中都生成了穩(wěn)定的iPS細(xì)胞。然后,，與2A結(jié)合在一起的重新編程因子（在已經(jīng)生成的iPS細(xì)胞系中是不需要的）被除去,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 458, 766-770 (9 April 2009) | doi:10.1038/nature07863
piggyBac transposition reprograms fibroblasts to induced pluripotent stem cells
Knut Woltjen1, Iacovos P. Michael1,2, Paria Mohseni1,2, Ridham Desai1,2, Maria Mileikovsky1, Riikka H?m?l?inen1, Rebecca Cowling1, Wei Wang3, Pentao Liu3, Marina Gertsenstein1, Keisuke Kaji4, Hoon-Ki Sung1 & Andras Nagy1,2
1 Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
2 Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada
3 The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
4 MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, University of Edinburgh, Edinburgh EH9 3JQ, UK
Transgenic expression of just four defined transcription factors (c-Myc, Klf4, Oct4 and Sox2) is sufficient to reprogram somatic cells to a pluripotent state1, 2, 3, 4. The resulting induced pluripotent stem (iPS) cells resemble embryonic stem cells in their properties and potential to differentiate into a spectrum of adult cell types. Current reprogramming strategies involve retroviral1, lentiviral5, adenoviral6 and plasmid7 transfection to deliver reprogramming factor transgenes. Although the latter two methods are transient and minimize the potential for insertion mutagenesis, they are currently limited by diminished reprogramming efficiencies. piggyBac (PB) transposition is host-factor independent, and has recently been demonstrated to be functional in various human and mouse cell lines8, 9, 10, 11. The PB transposon/transposase system requires only the inverted terminal repeats flanking a transgene and transient expression of the transposase enzyme to catalyse insertion or excision events12. Here we demonstrate successful and efficient reprogramming of murine and human embryonic fibroblasts using doxycycline-inducible transcription factors delivered by PB transposition13. Stable iPS cells thus generated express characteristic pluripotency markers and succeed in a series of rigorous differentiation assays. By taking advantage of the natural propensity of the PB system for seamless excision12, we show that the individual PB insertions can be removed from established iPS cell lines, providing an invaluable tool for discovery. In addition, we have demonstrated the traceless removal of reprogramming factors joined with viral 2A sequences14 delivered by a single transposon from murine iPS lines. We anticipate that the unique properties of this virus-independent simplification of iPS cell production will accelerate this field further towards full exploration of the reprogramming process and future cell-based therapies.
