Restriction endonuclease BsoFl is sensitive to the 5′-methylation of deoxycytidines in its recognition sequence

Abstract

The Isoschizomeric restriction endonucleases Fnu4HI and BsoFI cleave DNA at 5′-GC↓NGC-3′ sequences. Fnu4HI has been shown to be inhibited by 5′-CG-3′ methylation in the sequences 5′-GmCGGC-3′ or 5′-GCGGmCG-3′. We have now investigated the methylation sensitivity of BsoFI by testing its activity on plasmid DNA 5′-CG-3′ methylated with the M.Sssl DNA methyltransferase or on synthetic (CGG)n repetitive oligodeoxyribonucleotides which have been partly or completely C methylated. The data demonstrate that BsoFI cannot cleave at its recognition sequence when It is completely 5′-CG-3′ methylated. These enzymes have proven to be useful in analyses of the methylation status in (CGG)n repeats of the human genome. © 1995 Oxford University Press.