I keep telling you guys this, but some of you non-developmental biologists dare to disagree — but it’s true, I’ma gonna tell you, developmental biology is the greatest scientific discipline of all time. We have confirmation, too: The Nobel Prize in Physiology or Medicine for 2012 has been announced, and it goes to two developmental biologists, John Gurdon (about time) and Shinya Yamanaka. It also goes for research in stem cells.
Gurdon carried out the initial crucial experiment years ago. He sucked the nucleus out of an adult frog skin cell and injected it into an enucleated frog egg. What happened next was that in some cases, the nucleus was reprogrammed into a pluripotent state — instead of being a skin cell with its specific suite of active and inactive genes, it was transformed into an egg cell equivalent, and went on to divide and dutifully create a genetic copy of the donor frog…a clone. This was the precursor to all the animal cloning experiments that have gone on since.
Gurdon’s experiment worked, but we didn’t know how — we knew that the environment of the cytoplasm of the egg cell somehow reset the epigenetic state of the skin cell nucleus, but we were blind to what was actually doing the work.
Enter Yamanaka and his colleagues. What they did was figure out what genes constituted the reset button of the cell, and by expressing them could force adult cells to revert to a pluripotent state. Their approach is a kind of brute force global activation of the four genes identified as key triggers in mammalian cells, but it works: adult mouse cells have been transformed, and then go on to develop into clones of the donor, and it also works on human cells, although no full human clones have been produced — just tissue collections in a dish, or teratomas in mouse hosts.
These are important steps in developing tools to allow us to sculpt adult cells into tissues and organs and whole organisms. Notice that the work was done at Cambridge and Kyoto which, for the geographically challenged, are not American universities. There is good stem cell work being done in the US, but it’s hampered by regulations and restrictions that European and Asian universities do not suffer from. Unleash all the developmental biologists, because we must rule all the things everywhere!