Abstract
Visualization of DNA damage response protein recruitment to DNA damage sites enables measurement of the DNA damage. DNA double-strand breaks (DSBs) and blocked replication forks induce the phosphorylation of H2AX at serine 139 (γH2AX), and accumulate γH2AX which can then be detected as foci. The detection of γH2AX foci by immunostaining with antibodies that recognize γH2AX is an indicator of DSBs presence. This chapter describes the measurement of γH2AX immunostaining using a high-content imaging platform in chicken DT40 B-lymphocyte cell lines.