Methylation at CpG sequences does not influence histone H1 binding to a nucleosome including a Xenopus borealis 5 S rRNA gene.

We demonstrate that methylation of the 12 dinucleotide CpGs within a GC-rich DNA fragment containing a Xenopus borealis 5 S rRNA gene does not influence histone H1 binding to naked or nucleosomal 5 S DNA. Thus a simple mechanism in which histone H1 selectively associates with nucleosomes containing methylated CpG cannot explain the repressive effects of methylation on gene activity.