Analysis of a null mutation in the Drosophila splicing regulator Tra2 suggests its function is restricted to sexual differentiation

Tra2 is a regulator of pre-mRNA splicing and a key component of the Drosophila somatic sex determination pathway. Functional orthologs of this protein are thought to perform nonsex-specific functions essential for viability in both vertebrates and nematodes. Although Drosophila Tra2 is expressed throughout the soma of both sexes, studies on it have focused only on the sex-specific phenotypes of known viable alleles. Here we show that that widely used tra2 mutant alleles have residual activity and are not suitable for evaluating its effect on viability. To test whether Tra2 has an essential role in development, we generated a transposon-induced deletion in critical coding sequences. We find that tra2 deletion adults can survive as well as their heterozygous siblings. Thus, in contrast to other organisms, Tra2 is not required in Drosophila for general viability under laboratory conditions.