RT Journal Article SR Electronic T1 Polycomb Group Proteins as Epigenetic Mediators of Neuroprotection in Ischemic Tolerance JF Science Signaling JO Sci. Signal. FD American Association for the Advancement of Science SP ra15 OP ra15 DO 10.1126/scisignal.2000502 VO 3 IS 111 A1 Stapels, Martha A1 Piper, Chelsea A1 Yang, Tao A1 Li, Minghua A1 Stowell, Cheri A1 Xiong, Zhi-gang A1 Saugstad, Julie A1 Simon, Roger P. A1 Geromanos, Scott A1 Langridge, James A1 Lan, Jing-quan A1 Zhou, An YR 2010 UL http://stke.sciencemag.org/content/3/111/ra15.abstract AB Exposing the brain to sublethal ischemia affects the response to a subsequent, otherwise injurious ischemia, resulting in transcriptional suppression and neuroprotection, a response called ischemic tolerance. Here, we show that the proteomic signature of the ischemic-tolerant brain is characterized by increased abundance of transcriptional repressors, particularly polycomb group (PcG) proteins. Knocking down PcG proteins precluded the induction of ischemic tolerance, whereas in an in vitro model, overexpressing the PcG proteins SCMH1 or BMI1 induced tolerance to ischemia without preconditioning. We found that PcG proteins are associated with the promoter regions of genes encoding two potassium channel proteins that show decreased abundance in ischemic-tolerant brains. Furthermore, PcG proteins decreased potassium currents in cultured neuronal cells, and knocking down potassium channels elicited tolerance without preconditioning. These findings reveal a previously unknown mechanism of neuroprotection that involves gene repressors of the PcG family.