title: Active X chromosome DNA is unmethylated at eight CCGG sites clustered in a guanine-plus-cytosine-rich island at the 5' end of the gene for phosphoglycerate kinase.
abstract: The 5' control region and first exon for human X-chromosome-linked phosphoglycerate kinase is contained in a G + C-rich island. We measured methylation at all HpaII sites in this 5' region of leukocyte DNA. By use of a blotting procedure that allows analysis of small DNA fragments, we found that the HpaII sites are entirely methylated when from an inactive X chromosome and entirely unmethylated when from an active one. In contrast, methylation of HpaII sites in more downstream regions of the gene is essentially the same in active and inactive X chromosomes.
mesh_terms: D001483:Base Sequence; D003596:Cytosine; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D005260:Female; D005796:Genes; D008040:Genetic Linkage; D006147:Guanine; D006801:Humans; D008297:Male; D008745:Methylation; D010735:Phosphoglycerate Kinase / Q000235:genetics*; D014960:X Chromosome
chemical_list: D006147:Guanine; D003596:Cytosine; D004247:DNA; D010735:Phosphoglycerate Kinase; D004262:DNA Restriction Enzymes