title: DNA methylation at a CCGG sequence in the large intron of the rabbit beta-globin gene: tissue-specific variations.
abstract: We have analysed DNA modification in a HapII site (CCGG) present in the major intron of the discontinuous rabbit beta-globin gene. In most somatic tissues, including erythroid and non-erythroid tissues, about 50% of the DNA is resistant to cleavage at this site by HapII, though 100% cleavage is found with the isoschizomer MspI. Since the former enzyme is unable to cleave CCGG sites if the internal C residue is 5-methyl C (and since methylation is the only form of CpG modification documented in animal DNA), while the latter enzyme cleaves DNA irrespective of methylation at this residue, we infer that 50% of the CCGG sites in the beta-globin gene intron are methylated in these tissues. The same site appears to be 100% methylated (judged by the same criterium) in sperm DNA and about 80% methylated in brain DNA. DNA from the rabbit SIRC cell line is entirely unmethylated at this site.
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D004262:DNA Restriction Enzymes; D005796:Genes; D005914:Globins / Q000096:biosynthesis*; D008745:Methylation; D009693:Nucleic Acid Hybridization; D011817:Rabbits; D014018:Tissue Distribution
chemical_list: D005914:Globins; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases; D004262:DNA Restriction Enzymes