A new type of rodent embryonic stem (ES) cell has been derived that is more similar to human ES cells than current mouse alternatives. With human ES cells hard to come by, it's hoped that the new cells will prove a useful model that will boost our understanding of human stem cell biology.
Previously, it was thought that mouse ES cells could only be obtained from embryos before they had implanted into the uterus wall. Ronald D. G. McKay and colleagues and Ludovic Vallier and colleagues have now isolated rodent ES cells from embryos after they had implanted, from a tissue called the epiblast. Their studies are described in two Nature papers.
Unlike pre-implantation mouse ES cells, these new cells share many defining features with human ES cells. They grow like human ES cells, have similar patterns of gene expression and cell surface markers, and can produce many different cell types - as has already been shown for mouse ES cells.
Human ES cells are of interest from a basic biology and a therapeutic point of view, but researchers still need to understand fully the signals and processes that control their differentiation into specific cell types. The derivation of this new type of ES cell provides an experimental model to accelerate the use of human ES cells in science and medicine.
Ronald D. G. McKay (NINDS-NIH, Bethesda, MD, USA) Author paper 
Roger Pedersen (University of Cambridge, UK) Co-author paper 
Abstracts available online:
(C) Nature press release.
Message posted by: Trevor M. D'Souza