Correlation of mutagenesis level with expression of reparative enzyme O6-methylguanine DNA methyltransferase during establishment of cell lines in vitro

Long-term cultivation of cell lines inevitably leads to genetic and epigenetic changes. Aim. A comparative analysis of karyotype and level of the expression of reparative enzyme O 6 -methylguanine-DNA-methyltransferase (MGMT) at different stages of establishment and stabilization of human cell line 4BL and cell line of mouse germ cells G1. Methods. The set of methods was used to research the dynamics of karyotypes changes: the differential staining of chromosomes, FISH-method and comparative genomic hybridization. The level of MGMT expression was analyzed by PCR reaction and Western blot analysis. Results. General trends of establishment of mouse and human cell lines were revealed: at the first stage, which is characterized by increased structural instability of the genome, an increase in the MGMT expression was revealed while at the second stage of stabilization – a decrease in the expression. Therefore, almost complete disappearance of MGMT protein in unmodified form (24 kDa) is observed. Conclusions. Statistically significant correlation between MGMT repair enzyme and mutations induction processes during mammalian cell adaptation and cell line establishment to in vitro was described.