Nanos interacts with cup in the female germline of Drosophila

Nanos (Nos) is a translational regulator that governs abdominal segmentation of the Drosophila embryo in collaboration with Pumilio (Pum). In the embryo, the mode of Nos and Pum action is clear: they form a ternary complex with critical sequences in the 3'UTR of hunchback mRNA to regulate its translation. Nos also regulates germ cell development and survival in the ovary. While this aspect of its biological activity appears to be evolutionarily conserved, the mode of Nos action in this process is not yet well understood. In this report, we show that Nos interacts with Cup, which is required for normal development of the ovarian germline cells. nos and cup also interact genetically--reducing the level of cup activity specifically suppresses the oogenesis defects associated with the nos(RC) allele. This allele encodes a very low level of mRNA and protein that, evidently, is just below the threshold for normal ovarian Nos function. Taken together, these findings are consistent with the idea that Nos and Cup interact to promote normal development of the ovarian germline. They further suggest that Nos and Pum are likely to collaborate during oogenesis, as they do during embryogenesis.