Shinya Yamanaka won the Nobel Prize for developing a recipe of genetic factors that can turn back the clock of adult cells and make them behave like embryonic stem cells. But he would be the first to tell you his recipe ultimately may not be the best one for making these stem cells called iPS cells.

Virtually from the day he published his groundbreaking work, teams around the world have tried to develop new formulas that get around some problems with the original. One issue is the low efficiency of getting true stem cells. Another is the high rate of genetic aberrations that can be produced in the resulting stem cells.

Now, a team pairing researchers at the Hebrew University in Jerusalem and the Whitehead Institute in Cambridge, Massachusetts, has published a new recipe that seems to yield many more true stem cells, ones that are called pluripotent because they can make all cell types. The new cells also seem to have fewer genetic alterations, which could make them safer for clinical use in people.

They made the improved cells by moving from OSKM to SNEL—from the original genetic factors, Oct4, Sox2, Klf4 and Myc, to Sall4, Nanog, Esrrb and Lin28. An elaborate computer analysis of the function of genes helped them come up with the formula.

This work used mouse cells, so up next on their agenda is coming up with a similar formula that works in human cells. HealthCanal ran the university’s press release and Genetic Engineering & Biotechnology News ran a slightly more technical analysis of the work.

Don Gibbons