Practice question

Predominant advantage of EdU assay over BrdU is preservation of cellular architecture because it avoids harsh DNA denaturation. BrdU detection requires unwinding double helix using strong acid, heat, or enzymatic digestion to expose concealed bromo-deoxyuridine epitope for anti-BrdU antibody of large size 150 kDa that cannot access double-stranded DNA. These treatments hydrolyze fluorescent proteins such as GFP, destroy conformational epitopes of surface antigens CD markers, fragment histology, alter light scatter properties in flow cytometry, and distort cell cycle distributions. EdU click detection employs small organic azide dye around 1 kDa that diffuses freely into intact duplex forming covalent triazole without strand separation. Consequently morphology remains intact under phase-contrast, immunophenotype retains antigenicity enabling co-detection of stem markers, and compatibility with DNA content dyes propidium iodide or DAPI remains high without acid-induced artifacts. Sensitivity improves due to quantitative triazole formation, protocol duration reduces significantly, and multiplex capability expands making EdU preferred for tissue sections, whole mount embryos, and high-content imaging.