The role of micronuclei in chromatin elimination

Abstract

Micronuclei are the extra-nuclear chromatin compartments separated from the primary nucleus and surrounded by their own nuclear envelope. For a long time it has been thought that micronuclei is the final stage of the pathological process in a cell. They have been used as biomarkers of the influence of genotoxic factors as well as of genome instability in various diseases. Nowadays, it is demonstrated that micronuclei could be involved in the cellular activities, affect the nuclear genome and lead to the changes in cell and tissue physiology. It is known that the formation of micronuclei is one of the steps in selective chromatin elimination in the ontogenesis of plant and animal species. The regions to be marked and eliminated from cell nucleus are recognized at the level of genome. This process is often accompanied by modifications with the heterochromatin formation, changes in the chromosome condensation and in the position of chromosomes in the nucleus. The processes observed in selective and non-selective chromatin elimination are similar to a great extent. The fact that the role of micronuclei in the cell functioning is not well-known yet, and the composition of the micronuclei and the ways of chromatin elimination could influence their role in the development of the pathogenesis, emphasizes the importance of additional studies for a more profound investigation of this phenomenon.