Evaluation of two new antibodies for recognition of CldU in DNA fiber assay applications

DNA fiber assays are indispensable tools for studying DNA damage and replication stress responses <i>in vivo</i> 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.