According to a study published in the journal Cell Stem Cell, scientists at the Institute for Research in Biomedicine (Barcelona) identified two proteins that are fundamental to conserving skin stem cells. The proteins—Dnmt3a and Dnmt3b—are crucial for the self-renewal of skin stem cells, as they trigger the first step of the genetic program of these cells. “It was surprising to see that two proteins that have always been associated with gene repression through DNA methylation are activated in the most transcriptionally active regions of stem cells,” says Lorenzo Rinaldo, Ph.D. student and author of the study. “We had never observed this activity, because we were unable to study the global distribution of Dnmt3a and Dnmt3b at the genomic level. Thanks to advances in sequencing techniques, more researchers are observing the very mechanism that we have described.” Of the 12,000 gene enhancers in the genome, about 300 are superenhancers related to stem cells. The two proteins exert their function in these regions in order to trigger the approximately 1,000 genes required for the self-renewing capacity of stem cells.