STRING OF PEARLS ENCODES DROSOPHILA RIBOSOMAL-PROTEIN S2, HAS MINUTE-LIKE CHARACTERISTICS, AND IS REQUIRED DURING OOGENESIS

The first allele of string of pearls (sop) was isolated as a recessive female sterile mutant in a P element enhancer trap screen. Oogenesis in homozygous sop females arrests at approximately stage 5. In additio n, homozygous flies of both sexes have Minute-like characteristics tha t include reduced bristles, delayed development and larval lethality. sop maps to 30D/E on chromosome 2L and encodes the Drosophila homolog of eukaryotic ribosomal protein S2. The gene is present in a single co py in the Drosophila genome and the level of mRNA present in mutant an imals is reduced. The identification of a mutant allele that blocks de velopment at a mid-stage of oogenesis may indicate that sop has a spec ific developmental role during oogenesis in addition to its general ro le in protein synthesis as a component of the small ribosomal subunit.