Research Highlights

• Subject Category:
  • Biotechnology

Published online: 24 July 2009 | doi:10.1038/nchina.2009.155

Stem cells: True pluripotency

Felix Cheung

Introduction

© (2009) Nature

Qi Zhou at the Chinese Academy of Sciences in Beijing, Fanyi Zeng at Shanghai Jiao Tong University and co-workers¹ have converted mouse fibroblasts into induced pluripotent stem (iPS) cells that are capable of generating live, fertile mouse pups. The result demonstrates that stem cells induced from fibroblasts and other somatic cells can attain the same level of pluripotency as stem cells extracted from embryos.

The researchers reprogrammed the mouse fibroblasts by forced expression of four transcription factors: Oct4, Sox2, Klf4 and c-Myc. They then cultured the cells in a serum-free replacement for conventional foetal bovine serum. On day 10, they detected colonies of iPS cells formed on the culture dishes.

The researchers derived the iPS cell lines on days 14, 20 (pictured top) and 36. They demonstrated the true pluripotency and developmental potential of day-20 iPS cells through a series of tests: by checking for pluripotency markers, injecting the cells into normal blastocysts to generate chimaeric mice, and injecting the cells into tetraploid blastocysts to produce embryos (pictured middle) that fully developed into live pups (pictured bottom). The last of these tests, known as tetraploid complementation assay, is the most stringent test for pluripotency and has only previously been demonstrated using embryonic stem cells, not iPS cells.

By the end of the study, the researchers generated 37 iPS cell lines, three of which produced 27 live mouse pups by tetraploid complementation. One of these pups, named Tiny, went on to impregnate a female and produce young of its own.

The authors of this work are from:
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Graduate University of Chinese Academy of Sciences, Beijing, China; Shanghai Institute of Medical Genetics, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China; Institute of Medical Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.

Reference

1. Zhao, X. Y. et al. iPS cells produce viable mice through tetraploid complementation. Nature doi:10.1038/nature08267 (2009). | Article | OpenURL