Ectopic expression of key reprogramming transgenes in somatic cells enables them 
to adopt the characteristics of pluripotency. Such cells have been termed 
induced pluripotent stem (iPS) cells and have revolutionized the field of 
somatic cell reprogramming, as the need for embryonic material is obviated. One 
of the issues facing both the clinical translation of iPS cell technology and 
the efficient derivation of iPS cell lines in the research laboratory is 
choosing the most appropriate somatic cell type for induction. In this study, we 
demonstrate the direct reprogramming of a defined population of neural stem 
cells (NSCs) derived from the subventricular zone (SVZ) and adipose 
tissue-derived cells (ADCs) from adult mice using retroviral transduction of the 
Yamanaka factors Oct4, Sox2, Klf4, and c-Myc, and compared the results obtained 
with a mouse embryonic fibroblast (mEF) control. We isolated mEFs, NSCs, and 
ADCs from transgenic mice, which possess a GFP transgene under control of the 
Oct4 promoter, and validated GFP expression as an indicator of reprogramming. 
While transduction efficiencies were not significantly different among the 
different cell types (mEFs 68.70 +/- 2.62%, ADCs 70.61 +/- 15.4%, NSCs, 68.72 
+/- 3%, p = 0.97), the number of GFP-positive colonies and hence the number of 
reprogramming events was significantly higher for both NSCs (13.50 +/- 4.10 
colonies, 0.13 +/- 0.06%) and ADCs (118.20 +/- 38.28 colonies, 1.14 +/- 0.77%) 
when compared with the mEF control (3.17 +/- 0.29 colonies, 0.03 +/- 0.005%). 
ADCs were most amenable to reprogramming with an 8- and 38-fold greater 
reprogramming efficiency than NSCs and mEFs, respectively. Both NSC iPS and ADC 
iPS cells were demonstrated to express markers of pluripotency and could 
differentiate to the three germ layers, both in vitro and in vivo, to cells 
representative of the three germ lineages. Our findings confirm that ADCs are an 
ideal candidate as a readily accessible somatic cell type for high efficiency 
establishment of iPS cell lines.