Endonucleases are enzymes responsible for DNA degradation. They are activated when any injury or threat affects the cell's genetic content. It is well known that sperm chromatin integrity is essential to perform the correct transmission of paternal genetic information and that DNA alterations can be detrimental to reproductive efficiency. Therefore, endonucleases activation in spermatic cells may compromise fertilization and embryonic development. The biotechnology of sperm-mediated gene transfer (SMGT) uses sperm cells as a vector to introduce foreign DNA into an oocyte during the fecundation process. The objective of this technique is the production of transgenic animals with an emphasis on the development and improvement of domesticated species. Endonucleases in sperm cells are activated in response to the interaction of foreign DNA. The murine species are more sensitive to endonucleases and the bovine species are more resistant to these enzymes when exposed to foreign DNA. The hypothesis of the present study is that bovine sperm has fewer endonucleases activity when compared to the murine species, or/and the genomic bovine DNA is less sensitive to these enzymes. So, the aim of this project is to evaluate in vitro endonuclease activities by combined studies with bovine and murine species. With these results, some cell biology processes might be elucidated and the SMGT technique may be improved for transgenic animal production in future studies.
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