Cytological evidence for 5-azacytidine-induced demethylation of the heterochromatic regions of human chromosomes
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
This work was aimed at studying the effects of the demethylating agent 5-azacytidine (5-azaC) on the constitutive heterochromatin of human chromosomes at the cytological level. Metaphase preparations from peripheral blood lymphocyte and lymphoblastoid cultures obtained by standard methods were treated with the agent. Labelling of the heterochromatic regions was achieved by the indirect immunostaining method using anti-5-methylcytosine (5MeC) monoclonal antibodies and peroxidase-tagged second antibodies. 4-Chloro-1-naphthol (4C1N) was used as the substrate. The rate of methylation of individual chromosomes or chromosome groups was measured as the frequency of binding of anti-5MeC antibodies to specific chromosome regions. The following results were obtained: (i) in control cultures high intra- and interindividual variability in the binding frequencies of anti-5MeC antibodies to the short arm region of the acrocentrics was observed; (ii) 5-azaC consistently affects the methylation status of the constitutive heterochromatin; (iii) preferential demethylation occurs in the heterochromatic regions of specific chromosomes; (iv) under our experimental conditions the demethylating effect of 5-azaC appears not to be related to the well-known uncoiling effect of this drug.
- Adams RLP (1990) DNA methylation (review).Biochem J 265: 309–320.
- de Capoa A, Felli MP, Baldini Aet al. (1988) Relationship between the number and function of human ribosomal genes.Hum Genet 79: 301–304.
- de Capoa A, Alexandre C, Felli MPet al. (1991) Inheritance of ribosomal gene activity and level of DNA methylation of individual gene clusters in a three generation family.Hum Genet 88: 146–152.
- Jones PA, Taylor SM (1980) Cellular differentiation, cytidine analogs and DNA methylation.Cell 20: 84–93.
- Jones PA, Taylor SM (1981) Hemimethylated duplex DNAs prepared from 5-azacytidine-treated cells.Nucleic Acids Res 9: 2933–2947.
- Kokalj-Vokac N, Almeida A, Viegas-Pequignotet al. (1993) Specific induction of uncoiling and recombination by azacytidine in classical satellite-containing constitutive heterochromatin.Cytogenet Cell Genet 63: 11–15.
- Lubit BW, Schreck RR, Miller OJ, Erlanger BF (1974) Human chromosome structure as revealed by an immunoperoxidase staining procedure.Exp Cell Res 89: 426–429.
- Miller OJ, Schnedl W, Allen J, Erlanger BF (1974) 5-methylcytosine localised in mammalian constitutive heterochromatin.Nature 251: 636–637.
- Montpellier C, Bourgeois CA, Niveleau Aet al. (1994) Detection of methylcytosine-rich heterochromain on banded chromosomes. Application to cells with various status of DNA methylation.Cancer Genet Cytogenet 78: 87–93.
- Okamoto E, Miller DA, Erlanger BF, Miller OJ (1981) Polymorphism of 5-methylcytosine-rich DNA in human acrocentric chromosomes.Hum Genet 58: 255–259.
- Reynaud C, Bruno P, Boullanger Pet al. (1991) Monitoring of urinary excretion of modified nucleosides in cancer patients using a set of six monoclonal antibodies.Cancer Lett 61: 255–262.
- Schreck RR, Breg WR, Erlanger BF, Miller OJ (1974) The use of antinucleoside antibodies to probe the organization of chromosomes denatured by ultraviolet irradiation.Exp Cell Res 88: 31–39.
- Schmid M, Haaf T, Grunert D (1984) 5-azacytidine-induced undercondensation in human chromosomes.Hum Genet 67: 257–263.
- Schweizer D (1981) Counterstain-enhanced chromosome banding.Hum Genet 57: 1–14.
- Cytological evidence for 5-azacytidine-induced demethylation of the heterochromatic regions of human chromosomes
Volume 4, Issue 4 , pp 271-276
- Cover Date
- Print ISSN
- Online ISSN
- Kluwer Academic Publishers
- Additional Links
- anti-5-methylcytosine antibody
- human chromosome
- Industry Sectors
- Author Affiliations
- 1. Department of Genetics and Molecular Biology, University of Rome ‘La Sapienza’, Rome, Italy
- 2. CNRS URA 1459 Institut Pasteur, Lyon, France