It was believed that cell differentiation process is irreversible and that terminally differentiated cells could not be transformed into any other cell type. With experiments on frogs in 1962, Gurdon showed that it is possible to obtain a whole new organism from the nucleus of somatic cell by transferring it to the enucleated oocyte. This was the first proof that cell differentiation is reversible and that differentiated cells can be reprogrammed to the pluripotent state. By cloning Dolly the sheep evidence that cell reprogramming is also possible in mammals was obtained. An important further breakthrough in the field of cell reprogramming was the discovery of Yamanaka and Takahashi, who in 2006 discovered that differentiated somatic cells could be reprogrammed into pluripotent state by forced expression of only four transcription factors (induced pluripotent stem cells - iPSC). Since then, several reprogramming methods have been developed, which use different strategies for the insertion of pluripotency associated transcription factors, either by DNA sequences insertion (retroviral and lentiviral vectors, linear DNA, transposonic vectors, adenoviral vectors, plasmid vectors) or direct input of recombinant proteins, mRNA, miRNA, components of the CRISPR system or small molecules. In the thesis, a comprehensive review of existing reprogramming methods was made and their advantages and disadvantages presented. The overview of the reprogramming methods is presented in a table that may be helpful in selecting the optimal method considering further applicative use of reprogrammed cells.
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