5-azacytidine produces differential undercondensation of alpha, beta and classical human satellite DNAs.
Fluorescence in situ hybridization employing human alphoid, beta and classical satellite DNA probes was performed on 5-azacytidine treated and untreated chromosomes obtained from human lymphocytes. The individual used in this study presented a polymorphism of constitutive heterochromatin of chromosomes 1 and 9 as revealed by in situ digestion with the restriction endonuclease Alul. Neither the alphoid nor the beta satellite DNA domains were susceptible to condensation-inhibition by 5-azacytidine. Only the classical satellite localized on chromosome 9 was affected. The constitutive heterochromatin size polymorphism was shown to depend mainly on variations of the classical satellite DNA domain. Therefore, condensation-inhibition, as a phenomenon which may modify the natural folding of the chromatin fibre, regionally affects human constitutive heterochromatin and seems to be dependent on the heterochromatic family.
Fernández
J L
JL
Departamento de Biología, Universidad Autónoma de Madrid, Spain.
Goyanes
V
V
Pereira
S
S
López-Fernández
C
C
Gosálvez
J
J
D001374:Azacitidine / Q000494:pharmacology*; D002478:Cells, Cultured; D002877:Chromosomes, Human / Q000187:drug effects* / Q000648:ultrastructure; D002878:Chromosomes, Human, Pair 1 / Q000648:ultrastructure; D002899:Chromosomes, Human, Pair 9 / Q000648:ultrastructure; D015342:DNA Probes; D004276:DNA, Satellite / Q000187:drug effects* / Q000648:ultrastructure; D006570:Heterochromatin / Q000648:ultrastructure; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008214:Lymphocytes / Q000648:ultrastructure
D015342:DNA Probes; D004276:DNA, Satellite; D006570:Heterochromatin; D001374:Azacitidine