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January 2004
Active sperm from stem cells
Embryonic stem cells, the versatile master cells of the preimplantation embryo, can differentiate in vitro into a multitude of cell types. That used not to include germ cells, but two groups recently produced oocyte and sperm cells from embryonic stem cells. And now Geijsen et al. report that stem cells can be coaxed to form sperm that can actually fertilize eggs and produce early-stage embryos. Starting with embryonic stem cells from a very early stage mouse embryo called a blastocyst, the cells were cultured to form embryoid bodies, spheres that contain a mix of versatile cells. Germ cells, a special type of cell which give rise to eggs and sperm, were isolated from these bodies. From these cells, male sex cells were grown in vitro. When they were injected into unfertilized mouse eggs, the resulting embryo contained a full chromosome complement and began to develop normally. It is not yet known whether the same method can give rise to live young. This may provide a useful tissue-culture system for studies of germline genetic modification, and suggests new approaches to the treatment of male infertility.
Derivation of embryonic germ cells and male
gametes from embryonic stem cells
NIELS GEIJSEN, MELISSA HOROSCHAK, KITAI KIM, JOOST
GRIBNAU, KEVIN EGGAN & GEORGE Q. DALEY
Nature 427, 148–154 (2004); doi:10.1038/nature02247
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Stem cells: How to make eggs and sperm
M. AZIM SURANI
Embryonic stem cells can develop into many specialized cell types in culture
dishes. It now seems that they can also generate primordial germ cells,
which then go on to form sperm and eggs.
Nature 427, 106–107 (2004); doi:10.1038/427106a
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