Cup is essential for mRNA translational repression during early oogenesis.

Study of the timing and location for mRNA translation across model systems has begun to shed light on molecular events fundamental to such processes as intercellular communication, morphogenesis, and body pattern formation. In , the posterior mRNA determinant, , is transcribed maternally but translated only when properly localized at the oocyte's posterior cortex. Two effector proteins, Bruno1 and Cup, mediate steps of mRNA regulation.