TRA2A is a member of the transformer 2 homolog family and encodes a protein with two RS domains and an RRM (RNA recognition motif) domain. Several alternatively spliced transcript variants of this gene have been described; however, the full-length nature of some of these variants has not been determined.Two alternative types of TRA2A cDNA clones were identified; each type encodes a different protein isoform with striking organizational similarity to Drosophila tra2 proteins. When expressed in flies, one TRA2-alpha isoform partially replaced the function of Drosophila tra2, affecting both female sexual differentiation and alternative splicing of dsx pre-mRNA. Like Drosophila tra2, the ability of TRA2-alpha to regulate dsx was female-specific and depended on the presence of the dsx splicing enhancer.