Sex-specific processing of the Drosophila exuperantia transcript is regulated in male germ cells by the tra-2 gene.

The Drosophila exuperantia (exu) gene encodes overlapping sex-specific, germline-dependent mRNAs. In this work, the structural differences between these sex-specific exu mRNAs were determined by sequence analysis of 9 ovary and 10 testis cDNAs. The transformer 2 (tra-2) gene functions in sex determination of female somatic cells through its role in regulating female-specific splicing of doublesex (dsx) RNA. We report here that tra-2 is required in male germ cells for efficient male-specific processing of exu RNA; in the absence of tra-2, X/Y males produce a new mRNA which is processed at its 3' end so that it contains sequences normally specific to the female 3' untranslated region. Although the processing event that requires tra-2 occurs in an untranslated region of the exu transcript, the isolation and characterization of a male-specific exu allele which deletes male 3' untranslated sequence indicate that this processing is biologically significant.