AFTER a long delay, researchers in the US who get federal funding have
learned which human embryonic stem cells they will be allowed to work with. The
National Institutes of Health has at last released the list of 72 approved cell
lines from 11 private and public institutions from around the world.
President Bush announced in August that federally funded research would be
allowed with a few existing cell lines. But the NIH鈥檚 stem cell registry
(http://escr.nih.gov) provides little information about these cell lines. Only a
few genetic markers are given even for the most studied lines, and it isn鈥檛
clear that all 72 really are true cell lines鈥攎eaning that they have been
derived from a single original cell.
That poses problems for researchers seeking the most suitable cells for their
work. Embryonic stem cells have got doctors excited because they can grow into
specialised tissues that could one day be used for transplants. But work with
mouse stem cells shows that not all cell lines have the same potential to
develop into differentiated tissues. If you want to study how stem cells can be
coaxed into becoming muscle, for example, finding a stem cell line that is good
at turning into muscle is vital.
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鈥淢y guess is that probably many people will start doing DNA microarray
analysis,鈥� says Minoru Ko of the NIH. Such tests can quickly reveal which of
thousands of genes are being expressed. Ko thinks these patterns of expression
are the key to understanding what potential a particular cell line has. 鈥淭hat
should be the way in the future to compare embryonic stem cells,鈥� says Ko. 鈥淚t
should give us some clues as to what are the differences.鈥�