In vitro produced embryos may be subject to (oxidative) stress which is responsible for decreased development and quality of those embryos in comparison with in vivo derived counterparts. Nevertheless, our own FWO-research has shown that short-term exposure of bovine oocytes to an exogenous H2O2-pulse at the end of maturation stimulated embryo development to the blastocyst stage. The aim of this project is to investigate the role of mitogen-activated protein kinases (MAPKs) and proteins such as heat-shock proteins, heat-shock factors, hypoxia-inducible factors, and nuclear factor (NF-kB) in embryo stress tolerance.