Doublesex (DSX) is a transcription factor that regulates somatic sexual differences in Drosophila. The structure of this domain has revealed a novel dimeric arrangement of ubiquitin-associated folds that has not previously been identified in a transcription factor [1].

1: Dimerization of doublesex is mediated by a cryptic ubiquitin-associated domain fold: implications for sex-specific gene regulation. Bayrer JR, Zhang W, Weiss MA; J Biol Chem. 2005;280:32989-32996. PMID:16049008