Scientists produce mouse eggs from embryonic stem cells, demonstrating totipotency eve...( PHILADELPHIA -- Researchers at the Univ...)

PHILADELPHIA -- Researchers at the University of Pennsylvania have created the first mammalian gametes grown in vitro directly from embryonic stem cells. The work, in which mouse stem cells placed in Petri dishes -- without any special growth or transcription factors -- grew into oocytes and then into embryos, will be reported this week on the web site of the journal Science.

The results demonstrate that even outside the body embryonic stem cells remain totipotent, or capable of generating any of the body's tissues, said lead researcher Hans R. Schler of Penn's School of Veterinary Medicine.

"Most scientists have thought it impossible to grow gametes from stem cells outside the body, since earlier efforts have yielded only somatic cells," said Schler, professor of reproduction medicine and director of Penn's Center for Animal Transgenesis and Germ Cell Research. "We found that not only can mouse embryonic stem cells produce oocytes, but that these oocytes can then enter meiosis, recruit adjacent cells to form structures similar to the follicles that surround and nurture natural mouse eggs, and develop into embryos."

Schler said oocyte development in vitro may offer a new way for embryonic stem cells to be produced artificially, sidestepping the ethical concerns articulated by President Bush and others. Implanting a regular nucleus from any of the body's cells into such an oocyte would yield a totipotent stem cell.

The findings may force legal revisions in nations such as Germany whose lawmakers, assuming that stem cells' potency outside the body was limited, have passed legislation banning research with totipotent stem cells.

The Penn scientists pulled off this feat using a gene called Oct4 as a genetic marker. After the stem cells were plated in a regular Petri dish -- densely but without special feeder cells or growth factors -- the scientists used fluorescent markers linked to Oct4 and other telltale genes to a
'"/>

Contact: Steve Bradt
bradt@pobox.upenn.edu
215-573-6604
University of Pennsylvania
1-May-2003

Page: 1 2
Related biology news :

1. Scientists to prototype cyberinfrastructure for research and education access to ocean observatories
2. Scientists sequence genome of kind of organism central to biospheres carbon cycle
3. Scientists find nanowires capable of detecting individual viruses
4. Scientists discover potential new way to control drug-resistant bacteria
5. Scientists explore genome of methane-breathing microbe
6. Scientists decipher genetic code of biothreat pathogen
7. Stuck on you: Scientists lay bare secrets of bacterial attachment proteins
8. Scientists discover proteins involved in spread of HIV-1 infection
9. Scientists fear new Ebola outbreak may explain sudden gorilla disappearance
10. Scientists reinvent DNA as template to produce organic molecules
11. Scientists visualise cellular handmaiden that restores shape to proteins