THE INFLUENCE OF IMMOBILIZED LAMININ ON KARYOTYPIC VARIABILITY IN TWO KARYOTYPIC DIFFERENT VARIANTS OF THE INDIAN MUNTJAC
SKIN FIBROBLAST CELL LINE
G. G. Poljanskaya, T. S. Goryachaya, G. P. Pinaev
Institute of Cytology RAS, St. Petersburg;
e-mail: poljansk@mail.cytspb.rssi.ru
The numerical and structural karyotypic variability has been investigated in the Indian muntjac skin fibroblasts "markerless" cell line MT and in its karyotypic
variant ÌÒä cultivated on the laminin 2/4 coated surface. In cell line MT preincubated in serum free medium for 2.5 and 1 h and then cultivated on the
laminin-coated surface in the serum-containing medium for 1, 2 and 3 days, the character of cell distribution for the chromosome number has changed. These
changes involve a significant decrease in frequency of cells with modal number of chromosomes, and an increase in frequency of cells with lower chromosomal
number. Some new additional structural variants of the karyotype (SVK) appeared. The observed alterations seem to be due to disturbances of chromosome
segregation and establishing a new advantageous balance karyotypic structure. The karyotypic variant ÌÒä distinguished from MT by the increased
number of dicentrics (telomeric associations) and cultivated under the same conditions showed no change in the character of cell distribution for the chromosome
number. In cell line MT, the frequency of chromosomal aberrations did not change relative to control variants. In karyotypic variant ÌÒä under the same
conditions the frequency of chromosomal aberrations significantly increases in 3 days mainly due to formation of dicentrics. These results confirm the conclusion that,
similarly to aneuploidy, formation of dicentrics in "markerless" cell lines appears to be the way for cell population to adapt to unfavourable factors of the environment.
Possible reasons for differences in the character of the numerical and structural karyotypic variability between cell line MT and its karyotypic variant MTä are
discussed.
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