Keywords: u. RNA binding proteins; x. translational regulation
In D. melanogaster, a subset of mRNAs essential for embryo development are spatio-temporally controlled during oogenesis. oskar mRNA is a critical transcript for germplasm assembly, which is translationally regulated by Bruno 1 and Cup. The current model suggests that Bruno 1 is the key factor for recruiting Cup to oskar mRNA that enables the formation of the translational silencing complex. Here, we address the spatio-temporal requirements for the formation of the Bruno 1-Cup complex contributing to a more universal understanding of mRNA regulation. Our work reveals that the Bruno 1-Cup interaction, as well as their interdependent influence on each other’s protein expression, lead to a precise oskar mRNA regulation. Cup mediates recruitment of oskar mRNA to P-bodies driving the translational repression and stability of oskar mRNA and inhibits Bruno 1’s role in the activation of translation. When Cup is removed from the complex, Bruno 1 is free to interact with Orb, thus facilitating translational activation.