Scientists Turn Mouse Stem Cells Into Egg Cells; Discovery Could Impact Future Medical Research
Researchers yesterday announced that they were able to cause stem cells from mouse embryos to transform into egg cells, a finding that could remove a major objection to research cloning and could "blur the biological line" between female and male reproduction, the Washington Post reports. The study, which appears in today's issue of Science, was conducted by Hans Scholer and Karin Huebner of the University of Pennsylvania School of Veterinary Medicine along with colleagues in France and Philadelphia (Weiss, Washington Post, 5/2). The researchers inserted a gene into a group of stem cells that would prompt cells to grow if they began to turn into eggs (Recer, AP/Philadelphia Inquirer, 5/2). The researchers gradually isolated these cells as having the genetic traits making them likely to develop into egg cells. These cells were removed from the mass of stem cells and placed in a separate laboratory dish. As the group of cells reached a "critical mass," they began to develop into egg cells and follicular cells -- cells found in ovaries that assist in the maturation of young egg cells (Washington Post, 5/2). The egg cells went on to form blastocysts through parthenogenesis, which is reproduction without sperm fertilization (AP/Philadelphia Inquirer, 5/2). While such "spontaneous embryos" are not viable because they contain an incomplete set of chromosomes, the eggs formed could probably be used for cloning, Scholer said, according to the AP/Baltimore Sun (AP/Baltimore Sun, 5/2).
The findings could hold major implications for research using embryonic stem cells, which are usually obtained from discarded human embryos and have the capacity to develop into the different cells found in the human body. Researchers have already been able to induce stem cells from mouse and human embryos to form brain, liver, pancreatic and other types of cells in the laboratory, and they hope to eventually use that technology to repair human tissue by creating new tissue identical to that of a patient (Wade, New York Times, 5/2). A large supply of human eggs would be required to make widespread use of this technology, but such eggs are now available only through harvesting from female donors, a potentially painful and risky surgical procedure. If scientists are able to produce human eggs using the same process the researchers used to create the mouse eggs, there would be no need for donors and an "almost limitless" supply of eggs, according to the the AP/Sun (AP/Baltimore Sun, 5/2). While researchers expect the process used on the mice cells will be similar to the process used for human cells, such research has not yet been undertaken. Dr. James Battey, chair of the stem cell task force at NIH, said that the researchers should not undertake experiments on humans until further ethical review and "opinion sounding" has been conducted, the Times reports (New York Times, 5/2).
The following broadcast programs reported on the study:
- NPR's "All Things Considered": The segment includes comments from researchers Schoeler, Jose Cibelli of Michigan State University and George Daley of the Whitehead Institute (Palca, "All Things Considered," NPR, 5/1). The full segment is available online in RealPlayer.
- NPR's "All Things Considered": NPR's Robert Siegel interviews Dr. Thomas Murray, president of the Hastings Center, about the study findings (Siegel, "All Things Considered," NPR, 5/1). The full segment is available online in RealPlayer.
- NPR's "Morning Edition": NPR's Bob Edwards interviews Johns Hopkins University stem cell researcher John Gearheart about the study findings (Edwards, "Morning Edition," NPR, 5/2). The full segment will be available online in RealPlayer after noon ET.