Abstract
DNA fiber assays are indispensable tools for studying DNA damage and replication stress responses in vivo at the single replication fork level. These assays typically rely on antibodies recognizing IdU and CldU. Historically, the availability of CldU-reactive antibodies has been limited to one reagent (clone BU1/75(ICR1)). We validated two alternative antibodies for CldU detection in DNA fiber assays. One of these antibodies can be readily paired with a common IdU-reactive antibody, and we confirmed that it produces quantitatively similar CldU track length results vis-à-vis the BU1/75 antibody. The new reagents should boost versatility of DNA fiber assays, facilitating DNA replication research.