Scientists produce mouse eggs from embryonic stem cells, demonstrating totipotency even in vitro

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. Schöler 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 Schöler, 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.”

Schöler 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 assay oocyte development. After 12 days in culture, the cells organized into colonies of variable size. Shortly thereafter, individual cells detached from these colonies.

“These germ cells then accumulated a coating of cells similar to the follicles surrounding mammalian eggs,” Schöler said. “Starting on day 26, oocyte-like cells were released into the culture — similar to ovulation — and by day 43, embryo-like structures arose through parthenogenesis, or spontaneous reproduction without sperm.”

In the experiment described this week in Science, both male- and female-derived stem cells developed into female gametes. Schöler and colleagues now plan to test whether oocytes developed in vitro can be fertilized.

“We would like to use these oocytes as a basis for therapeutic cloning, and hope that our results can be replicated with human embryonic stem cells,” Schöler said.

Schöler was joined in the research by Karin Hübner, James Kehler, Rolland Reinbold, Rabindranath de la Fuente and Michele Boiani of Penn’s School of Veterinary Medicine; Lane K. Christenson, Jennifer Wood and Jerome Strauss III from Penn’s School of Medicine; and Guy Fuhrmann of the Centre de Neurochimie in France. The work was funded by the National Institutes of Health, the Marion Dilley and David George Jones Funds, the Commonwealth and General Assembly of Pennsylvania and the Association pour la Recherche sur la Cancer.

Media Contact

Steve Bradt EurekAlert!

Weitere Informationen:

http://www.upenn.edu/

Alle Nachrichten aus der Kategorie: Life Sciences

Articles and reports from the Life Sciences area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Zurück zur Startseite

Kommentare (0)

Schreib Kommentar

Neueste Beiträge

Cyanobacteria: Small Candidates …

… as Great Hopes for Medicine and Biotechnology In the coming years, scientists at the Chair of Technical Biochemistry at TU Dresden will work on the genomic investigation of previously…

Do the twist: Making two-dimensional quantum materials using curved surfaces

Scientists at the University of Wisconsin-Madison have discovered a way to control the growth of twisting, microscopic spirals of materials just one atom thick. The continuously twisting stacks of two-dimensional…

Big-hearted corvids

Social life as a driving factor of birds’ generosity. Ravens, crows, magpies and their relatives are known for their exceptional intelligence, which allows them to solve complex problems, use tools…

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close