During natural fertilization, mammalian spermatozoa must pass through the zona pellucida before reaching the plasma membrane of the oocyte. It is assumed that this step involves partial lysis of the zona by sperm acrosomal enzymes, but there has been no unequivocal evidence to support this view. Here we present evidence that acrosin, an acrosomal serine protease, plays an essential role in sperm penetration of the zona. We generated acrosin-knockout (KO) hamsters, using an in vivo transfection CRISPR/Cas9 system. Homozygous mutant males were completely sterile. Acrosin-KO spermatozoa ascended the female genital tract and reached ovulated oocytes in the oviduct ampulla, but never fertilized them. In vitro fertilization (IVF) experiments revealed that mutant spermatozoa attached to the zona, but failed to penetrate it. When the zona pellucida was removed before IVF, all oocytes were fertilized. This indicates that in hamsters, acrosin plays an indispensable role in allowing fertilizing spermatozoa to penetrate the zona. This study also suggests that the KO hamster system would be a useful model for identifying new gene functions or analyzing human and animal disorders because of its technical facility and reproducibility.

• MeSH
• akrosin genetika   metabolismus   MeSH
• akrozom metabolismus   MeSH
• fertilizace in vitro MeSH
• genový knockout MeSH
• interakce spermie a vajíčka * MeSH
• křečci praví genetika   metabolismus   MeSH
• spermie enzymologie   fyziologie   MeSH
• zona pellucida metabolismus   MeSH
• zvířata MeSH
• Check Tag
• křečci praví genetika   metabolismus   MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

ESCs are most commonly derived from embryos originating from oocytes that reached metaphase II. We describe here a novel approach where ESCs with all pluripotency parameters were established from oocytes in which metaphase I was converted, from the cell cycle perspective, directly into metaphase II-like stage without the intervening anaphase to telophase I transition. The resulting embryos initiate development and reach the blastocyst stage from which the ESC lines are then established. Thus, our approach could represent an ethically acceptable method that can exploit oocytes that are typically discarded in in vitro fertilization clinics. Moreover, our results also indicate that the meiotic cell cycle can be converted into mitosis by modulating chromosomal contacts that are typical for meiosis with subsequent licensing of chromatin for DNA replication.

• MeSH
• buněčná diferenciace fyziologie   MeSH
• buněčné kultury metody   MeSH
• buněčné linie MeSH
• embryonální kmenové buňky cytologie   fyziologie   MeSH
• meióza fyziologie   MeSH
• mitóza genetika   fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši inbrední DBA MeSH
• myši MeSH
• oocyty cytologie   fyziologie   MeSH
• oogeneze fyziologie   MeSH
• partenogeneze fyziologie   MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH