The structural basis for selective binding of non-methylated CpG islands by the CFP1 CXXC domain

CXXC domain proteins bind to CpG DNA sequences and influence chromatin modification. Xu et al. report crystal structures of the CXXC protein CFP1, a component of the SETD1 histone H3K4 methyl transferase complex, and study the molecular mechanisms of DNA-binding specificity.