Monday, 3 August 2009

Scripps Team Also Make Mice from iPS Skin Cells

Scripps Team Also Make Mice from iPS Skin Cells Monday, 03 August 2009 A team at The Scripps Research Institute in La Jolla says it bred live mice from mouse skin cells, advancing a technique that could offer an alternative to the controversial use of embryonic stem cells. The work, reported online yesterday by the journal Nature, involves reprogramming normal cells to create what are known as induced pluripotent stem cells. In recent years, scientists have been studying these cells to see if they might be as useful as embryonic stem cells, the master cells that differentiate into more than 200 cell types in the body. The Scripps team, led by Assistant Professor Kristin Baldwin, is not the first to achieve the feat. Two teams of Chinese researchers, who published their findings online in Cell Stem Cell and Nature, reported success in similar experiments two weeks ago, creating mice that were as much as 95 percent genetically matched to the adult mouse whose cells were used. The first part of the team's new study involved gathering cells that were already "differentiated," i.e. developed into a particular cell type, such as skin, nerve, or muscle. In this case, the scientists worked with skin cells from foetal mice, though other cell types may also work. Viruses were then used to insert genes coding for four proteins, called reprogramming factors, into these cells' DNA. These reprogramming factors shifted the cells out of their normal differentiated state to a "pluripotent" state resembling that of embryonic stem cells, which allows the cells to produce a wide variety of cell types. This cellular rewiring caused the cells to change their size and shape so that after only 7 to 10 days they could not be visually distinguished from embryonic stem cells. The ultimate test of this developmental pluripotency was to generate live mice entirely from iPS cells. This week, the Baldwin team and two Chinese groups all reported that they had independently grown live mice from iPS cells all the way to fertile adulthood. The team’s best cell line produced live pups 13 percent of the time, compared with a 3.5 percent and 1 percent success rate reported by the Chinese teams. The Scripps team said it generated live mice in four of 15 cell lines generated in one experiment, compared with success rates of three in 37 and one in five for the Chinese teams. “We can’t say for sure yet, but it is possible that we may have identified a protocol more likely to produce mice that survive until birth than current methods in the field,” Baldwin said. Reference: Adult mice generated from induced pluripotent stem cells Michael J. Boland, Jennifer L. Hazen, Kristopher L. Nazor, Alberto R. Rodriguez, Wesley Gifford, Greg Martin, Sergey Kupriyanov & Kristin K. Baldwin Nature advance online publication 2 August 2009, doi:10.1038/nature08310 See also: Second Chinese Group Produce Mice from iPS Cells CellNEWS - Thursday, 23 July 2009 Mice Grown from iPS Cells by Chinese Researchers CellNEWS - Thursday, 23 July 2009 ......... ZenMaster


For more on stem cells and cloning, go to CellNEWS at http://cellnews-blog.blogspot.com/ and http://www.geocities.com/giantfideli/index.html

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