To turn on its genome—the full set of genes inherited from each parent—a mammalian embryo needs to relocate a group of proteins, researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA have discovered. The metabolic proteins, normally found in the energy-generating mitochondria of cells, move to the DNA-containing nuclei about two days after a mouse embryo is fertilized, according to the new study, led by senior author Utpal Banerjee.