Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

02.05.2003


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.

Steve Bradt | EurekAlert!
Further information:
http://www.upenn.edu/

More articles from Life Sciences:

nachricht BigH1 -- The key histone for male fertility
14.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Guardians of the Gate
14.12.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>