Long-term cultivation of Chinese hamster fibroblasts V-79 RJK under elevated temperature results in karyotype destabilization

Abstract

In this article, we show that long-term cultivation of Chinese hamster fibroblasts V-79 RJK at elevated temperature resulted in the selection of variants with genetic changes at the level of karyotype. Beginning at the first steps of thermoresistance (to a temperature of 40°C) selection, we identified a population of cells with changes in the karyotype (polyploidy, deletions, inversions, chromosomal translocations, cells with DM-chromosomes). Further cultivation was accompanied with selection of cells with breaks near centromeres and homogeneously staining regions on chromosomes. Nonspecific destabilization of the karyotype (at the initial stages of selection) was accompanied with increased gene expression of hsc70 (constitutive iso-form of heat shock protein of the HSP70 family) and pgp1 (p-glycoprotein membrane transporter). Expression of these genes returned to the basal level during long-term cultivation at the elevated temperature, but the cells retained karyotypic changes.