[DNA of some regions of constitutive heterochromatin is demethylated and decondensed in MRC5 and A431 cells].

It is believed that satellite DNA is compact and transcriptionally inert during interphase. We determined localization, range of compactization and methylation state of the centromeric and pericentromeric satellite DNA using the method of fluorescence hybridization in situ (FISH) combined with the antibody immunostaining against the methylated DNA. We investigated the tissue cells (the cells of placenta and lymphocytes), primary (MRC5 fibroblasts) and malignant (A431) cell cultures.