DNA (Cross-linking)

DNA cross-linking refers to the formation of covalent bonds between two nucleotides within DNA, either on the same strand (intrastrand) or between opposite strands (interstrand). This process can be triggered by various exogenous agents (such as chemotherapeutic drugs, UV light, or environmental toxins) or endogenous cellular processes. Cross-links disrupt essential cellular functions like DNA replication and transcription, often leading to cell death if not properly repaired. DNA-protein crosslinks are a related phenomenon where proteins become covalently attached to DNA through similar mechanisms—these are also highly toxic lesions requiring specialized repair systems.

Formation of covalent linkages within/between DNA strands, leading to replication and transcription blockage and subsequent cell death.