The overall aim of this project is to investigate the role of reactive oxygen species (ROS) in cell proliferation, differentiation and tissue regeneration upon brain injury in adult zebrafish. We want to determine whether ROS are increased in specific cell types or tissues during forebrain regeneration after physical trauma and how they participate in such regeneration processes. We have generated transgenic zebrafish lines expressing fluorescent biosensors for H2O2 to determine alterations in levels of this ROS species in different tissues and subcellular compartments in the brain. We combine these data with histological methods to determine expression changes of redox related genes to uncover mechanisms underlying such alterations. In addition, we will perform redox proteomics studies to map changes in the redox state of cysteine residues of proteins between injured an uninjured forebrain hemispheres that provide candidates for redox-triggered downstream effectors guiding regeneration processes in the brain.