June 8, 2007
NEWS OF THE WEEK STEM CELLS: Reprogramming, Take Two
In the same issue of Nature, Harvard's Kevin Eggan reported another reprogramming advance: nuclear transfer (also called research cloning) using a fertilized mouse egg, or zygote. Early attempts in the 1980s to clone animals by transferring the nucleus of a somatic cell into a zygote failed, leading to a focus on doing the procedure with unfertilized oocytes. Human eggs, however, are difficult to obtain. Now Eggan and colleagues have shown that if nuclear DNA is removed from the dividing mouse zygote at just the right moment, it will successfully reprogram an introduced nucleus from a somatic cell. In this experiment, the researchers succeeded in creating both new lines of ES cells and apparently healthy cloned mice.
This work, says Cowan, suggests that to create patient-specific human ES cell lines, researchers could make use of fertilized eggs that would otherwise be discarded at fertility clinics, sidestepping the problematic issue of egg donation. "It's an exciting paper," says cloning researcher Robert Lanza of Advanced Cell Technology Inc. in Worcester, Massachusetts.
- Constance Holden

ARTICLE: Science 8 June 2007:_Vol. 316. no. 5830, p. 1404_DOI: 10.1126/science.316.5830.1404b