The overall goal of the proposed research is to determine the mechanism(s) of RNA transport into, and localization within, the Drosophila oocyte and to relate such processes to the establishment of dorsoventral pattern in the mature egg and early embryo. This research is focused on the Drosophila dorsoventral patterning gene 'fs(1)K10(K10)'. 'K10' RNA is synthesized in ovarian nurse cells and selectively transported via cytoplasmic bridges into the oocyte during early to middle stages of oogenesis. Several other Drosophila RNAs that play critical roles in egg and embryonic pattern fromation, including 'oskar' and 'bicoid', are also synthesized in nurse cells and selectively transported into the oocyte. There is growing evidence that 'K10', 'oskar' and 'bicoid' RNA transport occurs along microtubule tracts and therefore is similar in mechanism to the transport/localization of RNA and organelles in higher organisms. The proposed studies seek to identify and characterize the cis- and trans-acting regulators of 'K10' RNA transport. An investigation of 'K10' protein function will also be carried out. The PI's interest in this stems from the observation that 'K10' is required for the localization within the oocyte of 'gurken' RNA, which encodes a TGFalpha-like signaling molecule required for the asymmetric differentiation of the oocyte's neighboring somatic follicle cells. The proposed studies represent a molecular, genetic, and biochemical approach to the problem of RNA localization/transport and utilize mutagenesis, germ- line transformation, protein-nucleic acid binding, in situ hybridization, and immunocytochemical techniques.