Yesterday, a new paper in Nature from Ihor Lemischka’s lab at Princeton added to the growing list of genes important for maintaining pluripotency in embryonic stem cells. The paper by first author Natalia Ivanova builds upon a 2002 work from the same lab (see here) and sheds more light on what it takes to remain an embryonic stem cell. Using an informed library of short hairpin RNA’s, the genes Nanog and Oct-4 were found to remain central players (good thing too) but a few more team members have been added to the roster including Tbx3, Esrrb, and Dppa4 (a relative of the germ cell gene Stella or Dppa3). The balanced gene expression required to maintain pluripotency is delicate. A move to differentiate into any one of the early lineages appears to result from a shift in relative expression between members of this group. One cool thing is that there is more complexity yet to be revealed. The authors also counted a few EST’s among the hits in their pluripotency screen. Stay tuned…