Study of the activity of integrase of retrotransposone Gypsy Drosophila melanogaster in vitro

Introduction of retrotransposone gypsy in the genome of Drosophila melanogaster occurs specifically and is performed by integrase of this mobile element. Gypsy integrase is capable not only of introduction but also of precise excision of retrotransposon DNA from the target site. In the present work, we study the endonuclease activity of recombinant integrase gypsy in vitro. It is indicated that the enzyme hydrolyzes the substrate, forming single-chain and double-chain breaks. Conformation of the substrate greatly influences hydrolysis: integrase conducts double-chain breaks only in a supertwisted circular DNA molecule. The data make it possible to understanding the integration mechanism of retroviruses and transposition of mobile elements.