ANTISENSE SUPPRESSION OF THE PUTATIVE RIBOSOMAL-PROTEIN S3A GENE DISRUPTS OVARIAN DEVELOPMENT IN DROSOPHILA-MELANOGASTER

The Drosophila melanogaster homologue of the Anopheles gambiae C3 cDNA has been isolated and characterized by sequence analysis. The encoded protein was localized by immunochemical and immunocytochemical method s. The Drosophila C3 protein is highly similar to homologues of disput ed function, which have previously been identified in fungi, plants an d animals. The protein is ubiquitous and localized in the cytoplasm. C ell fractionation followed by detection with a specific antibody prepa ration shows that the protein is associated with the 40S ribosomal sub unit. The C3 gene is located in section 101F of chromosome 4. Antisens e transgenic analysis shows that this gene is essential for oogenesis. The most prominent phenotype resulting from antisense depletion of C3 RNA is disappearance of the follicular cells of the ovary (where the concentration of C3 protein is normally high) and abnormalities of the associated germline derivatives, leading to failure of egg production .