DNA OF SOME REGIONS OF CONSTITUTIVE HETEROCHROMATIN IS DEMETHYLATED AND DECONDENSED IN MRC5 AND A431 CELLS
I. S. R. Vaisertreiger, O. I. Podgornaya, N. I. Enukashvily 1
Institute of Cytology RAS and Municipal Consultation-Diagnostic Medical Genetics Centre, St. Petersburg;
1 e-mail: natella@mail.cytspb.rssi.ru
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. Centromeric satellite DNA was condensed and stained with antibodies against
5-methylcytosine in all the cases. Pericentromeric satellite 3 of the chromosome 1 was condensed in lymphocytes,
placenta cells and young culture of fibroblasts. The unwrapping of satellite 3 of the chromosome 1 has been observed
in the senescent MRC5 fibroblasts and in the malignant cell line A431. The compact areas of pericentromeric
satellites were stained with antibodies against the methylated DNA, white the decondensed areas were'nt stained.
Thus, we observed pericentromeric satellite 3 decondensation in senescent fibroblasts culture MRC5 and in cell line
A431. The decondensation was accompanied by the partial demethylation of the satellite DNA, which is believed to
belong to constitutive heterochromatin.
Key words: satellite DNA, human satellite 3, methylation, senescense
Back
Contents
Main
