We now know more of the reason why Ian Wilmut left the human cloning research behind. Researchers from two labs (Yamanaka in San Fran. and Japan, Thomson in Madison) have induced mature somatic cells to become embryonic-like stem cells, matching all the experimental criteria for embryonic stem cells. This new class of stem cells is called an inducible pluripotent stem cells (iPS cells). Both labs created these cells by using viruses to express key genes in the somatic cells.
This built off of Shinya Yamanaka’s earlier work on mice–in parallel, James Thomson–who isolated human embryonic stem cells in 1998, starting this whole debate–also created iPS cells, using different cells and a different mix of genes.
Many questions remain open: clearly, it would be best to avoid using viruses to transform these cells. One of the genes the Yamanaka lab used, c-myc, is an oncogene, something that we’d rather avoid using! I’d be interested in using something like a liposome loaded with mRNA for the key genes. There has been work on the genetic networks that maintain embryonic stem cell identity that may help that: use the mRNA to induce a transient shift in the right genes, and that may act as a switch to “turn on” the network, creating a stable iPS cell with no permanent genetic alternation.
But this is wide open, and we still have adult stem cells providing great results. I am particularly glad to see that two labs co-discovered this. It means that the work is more solid, and it also means that a monopoly on patents is less likely to stifle research. Embryonic stem cell research has been slower than many would like for a number of reasons. Many blame Bush, but this is only part of the reason. Much of the problem has been that the patents that Dr. Thomson generated are wide-ranging and have been mercilessly enforced by the Wisconsin Alumni Research Foundation, which holds the patents.