Regulation of Xvelo assembly by centrosomal proteins

The oocyte Balbiani body (Bb) is a conserved membraneless organelle required for germline specification in many species. Here we report that when overexpressed in mammalian somatic cells, Xenopus Velo (Xvelo), the Bb matrix protein could reconstitute a "Bb-like" structure, which shares key features of the oocyte Bb. Using this system, we investigated the potential mechanism of Bb assembly. We focused on the involvement of centrosomal proteins in this process, as both endogenous oocyte Bb and the "Bb-like" structure induced by Xvelo overexpression form around the centrosome. Our results reveal that multiple components of the centrosome can interact with Xvelo and promote Xvelo assembly to varying degrees. Moreover, knockdown of these proteins reduces Xvelo assembly. Our findings thus suggest that the interaction between centrosomal proteins and Xvelo may facilitate the initial aggregation of Xvelo, leading to the assembly of Bb around the centrosome in the oocyte.