WEHI-150 is an analog of mitoxantrone, a DNA interstrand cross-linker (t1/2=12.5 h). WEHI-150 is capable of forming covalent adducts on CpG sequences, with a particular preference for methylated CpG sites. Formaldehyde-activated WEHI-150 induces DNA interstrand cross-linking and blocks transcription in a concentration-dependent manner. WEHI-150 mediates the formation of covalent adducts that do not interact with guanine N-2 and forms adducts on new DNA sequences.