Non-uniform distribution of methylatable CCGG sequences on human chromosomes as shown by in situ methylation.
We carried out in situ methylation of human chromosomes with the HpaII methylase using [3H]methyl-S-adenosyl-L-methionine as the methyl group carrier. Autoradiographs localising [3H]methyl groups show methylatable CCGG sequences in the R-bands as well as in the short arms of the acrocentric chromosomes that include ribosomal DNA. The strongest labelling was observed over a subset of R-bands, including T-bands. Since methylatable CCGG sequences are representative of the unmethylated fraction of DNA, we suggest that differences in the degree of DNA methylation could be involved in the structure and function of chromosomal bands.
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Departamento de Biología, Universidad Autónoma de Madrid, Spain.
Ludeña
P
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Fernandez-Piqueras
J
J
D001483:Base Sequence; D002871:Chromosome Banding; D002877:Chromosomes, Human / Q000737:chemistry / Q000648:ultrastructure; D004247:DNA / Q000737:chemistry / Q000235:genetics*; D015257:DNA-Cytosine Methylases; D005260:Female; D006801:Humans; D008297:Male; D008745:Methylation
D004247:DNA; C029641:DNA modification methylase HpaII; D015257:DNA-Cytosine Methylases