Stem cells induced from somatic cells can be as pluripotent as stem cells extracted from embryos, as demonstrated in research online in Nature. A team from China created induced pluripotent stem (iPS) cell lines from mouse fibroblast, before showing that these cells could go on to generate fertile live mouse pups, the first born of which they named Tiny.
To demonstrate the pluripotency of stem cells, researchers can check for certain markers, inject them into normal blastocysts to generate a chimaera, or inject them into a tetraploid blastocyst - group of cells that can only become placental tissue. For this final technique, "tetraploid complementation", the cells being tested must form all of the cells of the embryo. It is considered the most stringent test for pluripotency and has been previously demonstrated using embryonic stem (ES) cells, but not using induced, iPS cells.
Qi Zhou, Fanyi Zeng and colleagues report the generation of 37 iPS cell lines, three of which produced 27 live offspring by tetraploid complementation. One of these, a 7-week-old male, went on to impregnate a female and produce young of its own.
Qi Zhou (Chinese Academy of Sciences, Beijing, China)
Fanyi Zeng (Shanghai Jiao Tong University, Shanghai, China)
(C) Nature press release.
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