Dynamic role of Scd1 gene during mouse oocyte growth and maturation

Mammalian reproductive ability is regulated by many factors, among which the fatty acid metabolism network provides energy for oocyte growth and primordial follicle formation during early mouse oogenesis. But the mechanism behind that is still unknown. Stearoyl-CoA desaturase 1 (Scd1) gene expression is increased during the oogenesis process, supporting the oocyte's healthy growth. Taking advantage of gene-edited mice lacking stearoyl-Coenzyme A desaturase 1 gene (Scd1^-/-), we analyzed relative gene expression in perinatal ovaries from wildtype, and Scd1^-/- mice. Scd1 deficiency dysregulates expression of meiosis-related genes (e.g., Sycp1, Sycp2, Sycp3, Rad51, Ddx4) and a variety of genes (e.g., Nobox, Lhx8, Bmp15, Ybx2, Dppa3, Oct4, Sohlh1, Zp3) associated with oocyte growth and differentiation, leading to a lower oocyte maturation rate. The absence of Scd1 significantly impedes meiotic progression, causes DNA damage, and inhibits damage repair in Scd1^-/- ovaries. Moreover, we find that Scd1 absense dramatically disrupts the abundance of fatty acid metabolism genes (e.g., Fasn, Srebp1, Acaca) and the lipid droplet content. Thus, our findings substantiate a major role for Scd1 as a multifunctional regulator of fatty acid networks necessary for oocyte maintenance and differentiation during early follicular genesis.