Isolation and Processing of Bovine Oocytes for Small RNA Sequencing.

In modern biomedical research, mice have been the mammalian model system of choice to investigate molecular pathways for potential future medical applications. Over the last years, it has become clear that female mice employ an exceptional piRNA pathway-independent mechanism to neutralize transposon activity in the ovary. In other model organisms studied to date, the piRNA pathway is indispensable for efficient targeting of transposable elements and fertility in both males and females. Moreover, recent studies have demonstrated that in other mammals, including humans, the piRNA pathway is highly active in the female germline as well, indicating that the situation in the mouse female germline is anomalous. For this reason, novel models to study piRNA pathways in female mammalian germlines are currently emerging, including Bos taurus. Here we describe a protocol for isolation and downstream processing of female bovine tissues in order to perform downstream applications including piRNA sequencing.