The aim of the thesis work was to perform transformation of ace2 deletion mutant with different length ace2-expressing plasmids to demonstrate whether the original phenotype of wild type Sch. pombe is restored. Ace2 gene is crucial, since it is responsible for complete daughter cells separation during cell division of fission yeast. After transformation, only few colonies have grown. Several techniques, including PCR reactions and gel electrophoresis, were performed in order to check the ace2 and plasmids presence. Under certain assumptions, it was concluded that low transformation success rate was due to cell wall thickening in mutant and too long sequences missing from the ace2 plasmids.