<Tr> <Td> Malondialdehyde </Td> <Td> </Td> <Td> </Td> <Td> Interstrand; 5' - GC, 5' - CG </Td> </Tr> <Tr> <Td> Oxidative Stress (and Radiation) </Td> <Td> </Td> <Td> </Td> <Td> Intrastrand; d (GpT) </Td> </Tr> <Tr> <Td> Nitrous Acid </Td> <Td> </Td> <Td> </Td> <Td> Interstrand; 5' - CG </Td> </Tr> <P> Crosslinked DNA is repaired in cells by a combination of enzymes and other factors from the nucleotide excision repair (NER) pathway, homologous recombination, and the base excision repair (BER) pathway.To repair interstrand crosslinks in eukaryotes, a 3' flap endonuclease from the NER, XPF - ERCC1, is recruited to the crosslinked DNA, where it assists in' unhooking' the DNA by cleaving the 3' strand at the crosslink site . The 5' strand is then cleaved, either by XPF - ERCC1 or another endonuclease, forming a double - strand break (DSB), which can then be repaired by the homologous recombination pathway . </P>

Briefly explain the difference between cross-linking and intercalating drugs