Image reproduced from Toyooka et al. (2008). Development135, 909-918.

Image reproduced from Toyooka et al. (2008). Development135, 909-918.

The rat is a preferred physiological model for understanding some human health issues, but the inability to generate germline competent embryonic stem (ES) cells has inhibited its tractability. Now, Buehr et al. report the isolation of ES cells from rat blastocysts. They show that these cells differentiate into various tissue types in adult chimeric rats and that the ES cell genotype transmits to the offspring of chimeras. Although transgenic rats currently exist, knocking out genes through loss-of-function mutations or replacing genes through homologous recombination has not previously been possible. This work provides new possibilities to create rat models harboring specific genetic mutations that are relevant to human disease.

Buehr
M
,
Meek
S
,
Blair
K
,
Yang
J
,
Ure
J
,
Silva
J
,
McLay
R
,
Hall
J
,
Ying
QL
,
Smith
A
. (
2008
).
Capture of authentic embryonic stem cells from rat blastocysts
.
Cell
135
,
1287
1298
.