Editorial on the Research Topic Molecular and Cellular Physiology of Gametes in Domestic and Wild Animal Models Gamete physiology contributes not only to the zygote formation but also to early embryo development. In mammals, most of the knowledge has been acquired from research on the murine and human models. This topic fills the information gap related to the effect of male and female microenvironments over sperm physiology from different species and offers critical and new insights into the

more »

... lecular mechanism of gametes' maturation to acquire fertilizing competence in wild and domestic animals. It includes 16 original research articles divided into three Research Topic: 1) oocyte maturation; 2) sperm fertilizing ability in response to female reproductive environment, and 3) molecular evaluation of seminal plasma related to sperm quality. 1) Oogenesis has been studied in mammalian and non-mammalian organisms, however to date, the mouse has been the most studied model. Knowledge of how conserved or distinctive are both nuclear and epigenetic molecular mechanisms of oocyte maturation and development in farm and wild animals would help to delineate complex molecular mechanisms and identify major genes and proteins involved. In this direction, nuclear proteins such as chromatin and ribosomal binding proteins have been identified as conserved molecular actors. Here, Chavez et al. identify nuclear BRD2 and NPM1 as novel factors that contribute to oocyte meiotic competence in the domestic cat. By transfecting complex-oocyte-cumulus with specific antibodies against these proteins they showed that BRD2 and NPM11 inhibited in vitro fertilization and oocytes were arrested at the germinal vesicle (GV) stage. Other nuclear proteins are known to interact with the kinetochore during the spindle formation controlling chromosome segregation during meiosis. Unlike rodents, mares have prolonged reproductive scenes and it is shown that three spindle related mRNAs are downregulated during aging: Mps1, Spc25 and AurkC (Rizzo et al.). Moreover, after pharmacological inhibition of MPS1 kinase, MII oocytes from aged mares showed a higher incidence of spindle abnormalities while AURKC inhibition severely impaired microtubule organization and spindle formation in all oocytes, irrespective of mare age. On the other hand, non-nuclear proteins have been also found to be implicated in spindle organization during oocyte maturation. In sheep, Han et al. showed that CLTC is localized in the oocytes spindle after GV break-down. Knockdown of the membrane protein CLTC by morpholino injection into GV oocytes disrupted spindle assembly and chromosome alignment, accompanied by impaired first polar body emission and altered early embryo development. Regarding extracellular factors, the dialog between the oocyte and surrounding granulosa/ cumulus cells operates through cytoplasmic projections-gap-junctions and through soluble molecules with specific receptors. Idrees et al. explores a novel role for a SHP2-ERa complex in the nucleus of bovine cumulus cells. The SHP2/ERa complex is highly expressed in the cumulus cells