question: What happens to H2AX upon DNA bouble strand breaks?
answer:  Phosphorylated H2AX (γH2AX) is rapidly concentrated in chromatin domains around DNA double-strand breaks (DSBs) after the action of ionizing radiation or chemical agents and at stalled replication forks during replication stress The nuclear foci of phosphorylated histone H2AX (γH2AX) are frequently used as a marker for DNA double-strand breaks (DSBs) following ionizing radiation (IR)