Recently reprogramming of somatic cells from a differentiated to plunpotent state by over expression of specifie external transcription factors has been accomplished. lt has been widely speculated that an undifferentiated state may make donor cells more efficient for nuclear transfer. To test this hypothesis we derived induced pluripotent stem cells (iPS cells) from severa! somatic cell lines: mouse embryonic fibroblast (MEF), adult tail tip fibroblast (TTF) and brain neurons stem cells (NSC). 30-FISH and 0-FISH were then used to evaluate constitutive (pericentric and telomeric) heterochromatin mganization in these iPS cells and in their parental differentiated cells. Here, we show that important nuclear remodeling and telomeres rejuvenation occurs in these iPS cells regardless of their parental origin. When we used these · cells as donors for nuclear transfer, we produced live-born cloned mice at much higller rates with the iPS-induced cells than with the parental cell !ines. lnterestingly, we noticed that developmental potential after nuclear transfer could be correlated with telomere length of the donor cells. Altogether, our findings suggest !hat constitutive heterochromatin organization from differentiated somatic cells can be reprogrammed to the pluripotent state by induction of iPS cells, which in turn support nuclear transfer procedure quite efficiently.