The sex-determining gene tra-2 of Drosophila encodes a putative RNA binding protein.

The gene transformer-2 (tra-2) of Drosophila is necessary not only for female sexual differentiation but also for normal spermatogenesis in males. We have cloned and characterized the tra-2 gene. Its putative protein has a domain that is homologous to RNA binding proteins. This suggests that the tra-2 protein might achieve the female-specific splicing of the transcript of dsx, a sex-determining gene whose mode of expression depends on tra-2. The protein coding region of the tra-2 transcript is identical in males and females. In both sexes, a low level of transcript is present in the soma and a high level in the germ line. This indicates that tra-2 is regulated in a way different from other sex-determining genes.